Merge remote-tracking branch 'origin/master'

.travis.yml

@@ -33,8 +33,6 @@ after_success:
 after_failure:
   - echo '*** Connected Test Rsults ***'
   - w3m -dump ${TRAVIS_BUILD_DIR}/app/build/reports/androidTests/connected/*Test.html
-  - echo '*** Lint Results ***'
-  - cat ${TRAVIS_BUILD_DIR}/app/build/reports/lint-results.xml
 jdk:
   # - openjdk8 # not yet available
   - oraclejdk8

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Wikimedia Commons for Android
 
+## v2.5.0 beta
+- Added one-time popup for beta users to provide feedback on IEG renewal proposal
+- Added link to Commons policies in ShareActivity
+- Various string fixes
+- Switched to using vector icons for map markers
+- Added filter for irrelevant categories
+- Fixed various crashes
+- Incremented target SDK to 25
+- Improved appearance of navigation drawer
+- Replaced proprietary app image in tutorial with one that isn't Telegram
+- Fixed camera issue with FileProvider
+- Added RxJava library, migrated to Java 8
+- Various code and continuous integration optimizations
+
 ## v2.4.2 beta
 - Added option to launch tutorial again from nav drawer
 - Added marker for current location in Nearby map

CREDITS

@@ -24,6 +24,8 @@ their contribution to the product.
 * Dmitry Brant
 * Adam Shorland
 * John Lubbock
+* Mikel Pascual
+* Jan Piotrowski
 
 3rd party open source libraries used:
 * Butterknife

app/build.gradle

@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply plugin: 'me.tatarka.retrolambda'
 apply plugin: 'jacoco-android'
 apply from: 'quality.gradle'
 apply plugin: 'com.getkeepsafe.dexcount'
@@ -51,8 +52,8 @@ android {
 
     defaultConfig {
         applicationId 'fr.free.nrw.commons'
-        versionCode 73
+        versionCode 74
-        versionName '2.4.2'
+        versionName '2.5.0'
         minSdkVersion project.minSdkVersion
         targetSdkVersion project.targetSdkVersion
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -75,6 +76,11 @@ android {
         abortOnError false
     }
 
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
     //FIXME: Temporary fix for https://github.com/commons-app/apps-android-commons/issues/709
     configurations.all {
         resolutionStrategy.force 'com.android.support:support-annotations:25.2.0'

app/src/main/java/fr/free/nrw/commons/CommonsApplication.java

@@ -11,6 +11,7 @@ import android.content.pm.PackageManager;
 import android.database.sqlite.SQLiteDatabase;
 import android.preference.PreferenceManager;
 import android.support.v4.util.LruCache;
+import android.util.Log;
 
 import com.facebook.drawee.backends.pipeline.Fresco;
 import com.facebook.stetho.Stetho;
@@ -139,6 +140,10 @@ public class CommonsApplication extends Application {
         System.setProperty("in.yuvi.http.fluent.PROGRESS_TRIGGER_THRESHOLD", "3.0");
 
         Fresco.initialize(this);
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(
+                CommonsApplication.getInstance());
+        // Increase counter by one, starts from 1
+        prefs.edit().putInt("app_start_counter", prefs.getInt("app_start_counter" ,0) + 1).commit();
 
         //For caching area -> categories
         cacheData  = new CacheController();
@@ -197,8 +202,8 @@ public class CommonsApplication extends Application {
 
         AccountManager accountManager = AccountManager.get(this);
         Account[] allAccounts = accountManager.getAccountsByType(AccountUtil.accountType());
-        for (int index = 0; index < allAccounts.length; index++) {
+        for (Account allAccount : allAccounts) {
-            accountManager.removeAccount(allAccounts[index], null, null);
+            accountManager.removeAccount(allAccount, null, null);
         }
 
         //TODO: fix preference manager 

app/src/main/java/fr/free/nrw/commons/Media.java

@@ -142,7 +142,7 @@ public class Media implements Parcelable {
         return coordinates;
     }
 
-    public void setCoordinates(LatLng coordinates) {
+    public void setCoordinates(@Nullable LatLng coordinates) {
         this.coordinates = coordinates;
     }
 
@@ -201,7 +201,7 @@ public class Media implements Parcelable {
         this.filename = filename;
     }
 
-    public Media(Uri localUri, String imageUrl, String filename, String description, long dataLength, Date dateCreated, Date dateUploaded, String creator) {
+    public Media(Uri localUri, String imageUrl, String filename, String description, long dataLength, Date dateCreated, @Nullable Date dateUploaded, String creator) {
         this();
         this.localUri = localUri;
         this.imageUrl = imageUrl;

app/src/main/java/fr/free/nrw/commons/WelcomeActivity.java

@@ -27,12 +27,7 @@ public class WelcomeActivity extends BaseActivity {
 
         pager.setAdapter(adapter);
         indicator.setViewPager(pager);
-        adapter.setCallback(new WelcomePagerAdapter.Callback() {
+        adapter.setCallback(this::finish);
-            @Override
-            public void onYesClicked() {
-                finish();
-            }
-        });
     }
 
     @Override

app/src/main/java/fr/free/nrw/commons/auth/LoginActivity.java

@@ -26,6 +26,9 @@ import fr.free.nrw.commons.PageTitle;
 import fr.free.nrw.commons.contributions.ContributionsActivity;
 import timber.log.Timber;
 
+import static android.view.KeyEvent.KEYCODE_ENTER;
+import static android.view.inputmethod.EditorInfo.IME_ACTION_DONE;
+
 
 public class LoginActivity extends AccountAuthenticatorActivity {
 
@@ -63,18 +66,8 @@ public class LoginActivity extends AccountAuthenticatorActivity {
         twoFactorEdit.addTextChangedListener(textWatcher);
         passwordEdit.setOnEditorActionListener(newLoginInputActionListener());
 
-        loginButton.setOnClickListener(new View.OnClickListener() {
+        loginButton.setOnClickListener(this::performLogin);
-            @Override
+        signupButton.setOnClickListener(this::signUp);
-            public void onClick(View v) {
-                performLogin();
-            }
-        });
-        signupButton.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                signUp(v);
-            }
-        });
     }
 
     private class LoginTextWatcher implements TextWatcher {
@@ -98,20 +91,17 @@ public class LoginActivity extends AccountAuthenticatorActivity {
     }
 
     private TextView.OnEditorActionListener newLoginInputActionListener() {
-        return new TextView.OnEditorActionListener() {
+        return (textView, actionId, keyEvent) -> {
-            @Override
+            if (loginButton.isEnabled()) {
-            public boolean onEditorAction(TextView textView, int actionId, KeyEvent keyEvent) {
+                if (actionId == IME_ACTION_DONE) {
-                if (loginButton.isEnabled()) {
+                    performLogin(textView);
-                    if (actionId == EditorInfo.IME_ACTION_DONE) {
+                    return true;
-                        performLogin();
+                } else if ((keyEvent != null) && keyEvent.getKeyCode() == KEYCODE_ENTER) {
-                        return true;
+                    performLogin(textView);
-                    } else if ((keyEvent != null) && keyEvent.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
+                    return true;
-                        performLogin();
-                        return true;
-                    }
                 }
-                return false;
             }
+            return false;
         };
     }
 
@@ -142,7 +132,7 @@ public class LoginActivity extends AccountAuthenticatorActivity {
         super.onDestroy();
     }
 
-    private void performLogin() {
+    private void performLogin(View view) {
         Timber.d("Login to start!");
         LoginTask task = getLoginTask();
         task.execute();

app/src/main/java/fr/free/nrw/commons/category/CategoriesAdapter.java

@@ -1,67 +0,0 @@
-package fr.free.nrw.commons.category;
-
-
-import android.content.Context;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.BaseAdapter;
-import android.widget.CheckedTextView;
-
-import java.util.ArrayList;
-
-import fr.free.nrw.commons.R;
-
-public class CategoriesAdapter extends BaseAdapter {
-
-    private LayoutInflater mInflater;
-
-    private ArrayList<CategorizationFragment.CategoryItem> items;
-
-    public CategoriesAdapter(Context context, ArrayList<CategorizationFragment.CategoryItem> items) {
-        this.items = items;
-        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
-    }
-
-    @Override
-    public int getCount() {
-        return items.size();
-    }
-
-    @Override
-    public Object getItem(int i) {
-        return items.get(i);
-    }
-
-    public ArrayList<CategorizationFragment.CategoryItem> getItems() {
-        return items;
-    }
-
-    public void setItems(ArrayList<CategorizationFragment.CategoryItem> items) {
-        this.items = items;
-    }
-
-    @Override
-    public long getItemId(int i) {
-        return i;
-    }
-
-    @Override
-    public View getView(int i, View view, ViewGroup viewGroup) {
-        CheckedTextView checkedView;
-
-        if(view == null) {
-            checkedView = (CheckedTextView) mInflater.inflate(R.layout.layout_categories_item, null);
-
-        } else {
-            checkedView = (CheckedTextView) view;
-        }
-
-        CategorizationFragment.CategoryItem item = (CategorizationFragment.CategoryItem) this.getItem(i);
-        checkedView.setChecked(item.selected);
-        checkedView.setText(item.name);
-        checkedView.setTag(i);
-
-        return checkedView;
-    }
-}

app/src/main/java/fr/free/nrw/commons/category/CategoriesAdapterFactory.java

@@ -0,0 +1,24 @@
+package fr.free.nrw.commons.category;
+
+import com.pedrogomez.renderers.ListAdapteeCollection;
+import com.pedrogomez.renderers.RVRendererAdapter;
+import com.pedrogomez.renderers.RendererBuilder;
+
+import java.util.Collections;
+import java.util.List;
+
+class CategoriesAdapterFactory {
+    private final CategoriesRenderer.CategoryClickedListener listener;
+
+    CategoriesAdapterFactory(CategoriesRenderer.CategoryClickedListener listener) {
+        this.listener = listener;
+    }
+
+    public RVRendererAdapter<CategoryItem> create(List<CategoryItem> placeList) {
+        RendererBuilder<CategoryItem> builder = new RendererBuilder<CategoryItem>()
+                .bind(CategoryItem.class, new CategoriesRenderer(listener));
+        ListAdapteeCollection<CategoryItem> collection = new ListAdapteeCollection<>(
+                placeList != null ? placeList : Collections.<CategoryItem>emptyList());
+        return new RVRendererAdapter<>(builder, collection);
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/CategoriesRenderer.java

@@ -0,0 +1,57 @@
+package fr.free.nrw.commons.category;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.CheckedTextView;
+
+import com.pedrogomez.renderers.Renderer;
+
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import fr.free.nrw.commons.R;
+
+class CategoriesRenderer extends Renderer<CategoryItem> {
+    @BindView(R.id.tvName) CheckedTextView checkedView;
+    private final CategoryClickedListener listener;
+
+    CategoriesRenderer(CategoryClickedListener listener) {
+        this.listener = listener;
+    }
+
+    @Override
+    protected View inflate(LayoutInflater layoutInflater, ViewGroup viewGroup) {
+        return layoutInflater.inflate(R.layout.layout_categories_item, viewGroup, false);
+    }
+
+    @Override
+    protected void setUpView(View view) {
+        ButterKnife.bind(this, view);
+    }
+
+    @Override
+    protected void hookListeners(View view) {
+        view.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                CategoryItem item = getContent();
+                item.setSelected(!item.isSelected());
+                checkedView.setChecked(item.isSelected());
+                if (listener != null) {
+                    listener.categoryClicked(item);
+                }
+            }
+        });
+    }
+
+    @Override
+    public void render() {
+        CategoryItem item = getContent();
+        checkedView.setChecked(item.isSelected());
+        checkedView.setText(item.getName());
+    }
+
+    interface CategoryClickedListener {
+        void categoryClicked(CategoryItem item);
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/CategorizationFragment.java

@@ -1,36 +1,33 @@
 package fr.free.nrw.commons.category;
 
 import android.content.ContentProviderClient;
-import android.content.DialogInterface;
 import android.content.SharedPreferences;
 import android.database.Cursor;
 import android.os.AsyncTask;
 import android.os.Bundle;
-import android.os.Parcel;
-import android.os.Parcelable;
 import android.os.RemoteException;
 import android.preference.PreferenceManager;
 import android.support.v4.app.Fragment;
 import android.support.v7.app.AlertDialog;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
 import android.text.Editable;
 import android.text.TextUtils;
 import android.text.TextWatcher;
-import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.CheckedTextView;
 import android.widget.EditText;
-import android.widget.ListView;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
+import com.pedrogomez.renderers.ListAdapteeCollection;
+import com.pedrogomez.renderers.RVRendererAdapter;
+
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
@@ -40,90 +37,191 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
+import butterknife.BindView;
+import butterknife.ButterKnife;
 import fr.free.nrw.commons.R;
+import fr.free.nrw.commons.category.CategoriesRenderer.CategoryClickedListener;
 import fr.free.nrw.commons.upload.MwVolleyApi;
 import timber.log.Timber;
 
+import static android.view.KeyEvent.ACTION_UP;
+import static android.view.KeyEvent.KEYCODE_BACK;
+import static fr.free.nrw.commons.category.CategoryContentProvider.AUTHORITY;
+
 /**
  * Displays the category suggestion and selection screen. Category search is initiated here.
  */
-public class CategorizationFragment extends Fragment {
+public class CategorizationFragment extends Fragment implements CategoryClickedListener {
-    public interface OnCategoriesSaveHandler {
+    public static final int SEARCH_CATS_LIMIT = 25;
-        void onCategoriesSave(ArrayList<String> categories);
-    }
 
-    ListView categoriesList;
+    @BindView(R.id.categoriesListBox)
-    protected EditText categoriesFilter;
+    RecyclerView categoriesList;
+    @BindView(R.id.categoriesSearchBox)
+    EditText categoriesFilter;
+    @BindView(R.id.categoriesSearchInProgress)
     ProgressBar categoriesSearchInProgress;
+    @BindView(R.id.categoriesNotFound)
     TextView categoriesNotFoundView;
+    @BindView(R.id.categoriesExplanation)
     TextView categoriesSkip;
-    private CategoryTextWatcher textWatcher = new CategoryTextWatcher();
-
-    CategoriesAdapter categoriesAdapter;
-    ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(2);
 
+    private RVRendererAdapter<CategoryItem> categoriesAdapter;
     private OnCategoriesSaveHandler onCategoriesSaveHandler;
-
+    private HashMap<String, ArrayList<String>> categoriesCache;
-    protected HashMap<String, ArrayList<String>> categoriesCache;
-
     private ArrayList<String> selectedCategories = new ArrayList<>();
-
+    private ContentProviderClient client;
+    private PrefixUpdater prefixUpdaterSub;
+    private MethodAUpdater methodAUpdaterSub;
+    private final CategoryTextWatcher textWatcher = new CategoryTextWatcher();
+    private final CategoriesAdapterFactory adapterFactory = new CategoriesAdapterFactory(this);
+    private final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(2);
+    private final ArrayList<String> titleCatItems = new ArrayList<>();
+    private final CountDownLatch mergeLatch = new CountDownLatch(1);
     // LHS guarantees ordered insertions, allowing for prioritized method A results
     private final Set<String> results = new LinkedHashSet<>();
-    PrefixUpdater prefixUpdaterSub;
-    MethodAUpdater methodAUpdaterSub;
 
-    private final ArrayList<String> titleCatItems = new ArrayList<>();
+    @SuppressWarnings("unchecked")
-    final CountDownLatch mergeLatch = new CountDownLatch(1);
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        View rootView = inflater.inflate(R.layout.fragment_categorization, container, false);
+        ButterKnife.bind(this, rootView);
 
-    private ContentProviderClient client;
+        categoriesList.setLayoutManager(new LinearLayoutManager(getContext()));
 
-    protected final static int SEARCH_CATS_LIMIT = 25;
+        categoriesSkip.setOnClickListener(view -> {
+            getActivity().onBackPressed();
+            getActivity().finish();
+        });
 
-    public static class CategoryItem implements Parcelable {
+        ArrayList<CategoryItem> items;
-        public String name;
+        if (savedInstanceState == null) {
-        public boolean selected;
+            items = new ArrayList<>();
-
+            categoriesCache = new HashMap<>();
-        public static Creator<CategoryItem> CREATOR = new Creator<CategoryItem>() {
+        } else {
-            @Override
+            items = savedInstanceState.getParcelableArrayList("currentCategories");
-            public CategoryItem createFromParcel(Parcel parcel) {
+            categoriesCache = (HashMap<String, ArrayList<String>>) savedInstanceState
-                return new CategoryItem(parcel);
+                    .getSerializable("categoriesCache");
-            }
-
-            @Override
-            public CategoryItem[] newArray(int i) {
-                return new CategoryItem[0];
-            }
-        };
-
-        public CategoryItem(String name, boolean selected) {
-            this.name = name;
-            this.selected = selected;
         }
 
-        public CategoryItem(Parcel in) {
+        categoriesAdapter = adapterFactory.create(items);
-            name = in.readString();
+        categoriesList.setAdapter(categoriesAdapter);
-            selected = in.readInt() == 1;
+        categoriesFilter.addTextChangedListener(textWatcher);
-        }
 
-        @Override
+        startUpdatingCategoryList();
-        public int describeContents() {
-            return 0;
-        }
 
-        @Override
+        return rootView;
-        public void writeToParcel(Parcel parcel, int flags) {
+    }
-            parcel.writeString(name);
+
-            parcel.writeInt(selected ? 1 : 0);
+    @Override
+    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+        menu.clear();
+        inflater.inflate(R.menu.fragment_categorization, menu);
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+
+        View rootView = getView();
+        if (rootView != null) {
+            rootView.setFocusableInTouchMode(true);
+            rootView.requestFocus();
+            rootView.setOnKeyListener((v, keyCode, event) -> {
+                if (event.getAction() == ACTION_UP && keyCode == KEYCODE_BACK) {
+                    backButtonDialog();
+                    return true;
+                }
+                return false;
+            });
         }
     }
 
+    @Override
+    public void onDestroyView() {
+        categoriesFilter.removeTextChangedListener(textWatcher);
+        super.onDestroyView();
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        client.release();
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        int itemCount = categoriesAdapter.getItemCount();
+        ArrayList<CategoryItem> items = new ArrayList<>(itemCount);
+        for (int i = 0; i < itemCount; i++) {
+            items.add(categoriesAdapter.getItem(i));
+        }
+        outState.putParcelableArrayList("currentCategories", items);
+        outState.putSerializable("categoriesCache", categoriesCache);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem menuItem) {
+        switch (menuItem.getItemId()) {
+            case R.id.menu_save_categories:
+
+                int numberSelected = 0;
+
+                selectedCategories = new ArrayList<>();
+                int count = categoriesAdapter.getItemCount();
+                for (int i = 0; i < count; i++) {
+                    CategoryItem item = categoriesAdapter.getItem(i);
+                    if (item.isSelected()) {
+                        selectedCategories.add(item.getName());
+                        numberSelected++;
+                    }
+                }
+
+                //If no categories selected, display warning to user
+                if (numberSelected == 0) {
+                    new AlertDialog.Builder(getActivity())
+                            .setMessage("Images without categories are rarely usable. "
+                                    + "Are you sure you want to submit without selecting "
+                                    + "categories?")
+                            .setTitle("No Categories Selected")
+                            .setPositiveButton("No, go back", (dialog, id) -> {
+                                //Exit menuItem so user can select their categories
+                            })
+                            .setNegativeButton("Yes, submit", (dialog, id) -> {
+                                //Proceed to submission
+                                onCategoriesSaveHandler.onCategoriesSave(selectedCategories);
+                            })
+                            .create()
+                            .show();
+                } else {
+                    //Proceed to submission
+                    onCategoriesSaveHandler.onCategoriesSave(selectedCategories);
+                    return true;
+                }
+        }
+        return super.onOptionsItemSelected(menuItem);
+    }
+
+    @Override
+    public void onActivityCreated(Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+        setHasOptionsMenu(true);
+        onCategoriesSaveHandler = (OnCategoriesSaveHandler) getActivity();
+        getActivity().setTitle(R.string.categories_activity_title);
+        client = getActivity().getContentResolver().acquireContentProviderClient(AUTHORITY);
+    }
+
+    public HashMap<String, ArrayList<String>> getCategoriesCache() {
+        return categoriesCache;
+    }
+
     /**
      * Retrieves category suggestions from title input
+     *
      * @return a list containing title-related categories
      */
-    protected ArrayList<String> titleCatQuery() {
+    private ArrayList<String> titleCatQuery() {
-
         TitleCategories titleCategoriesSub;
 
         //Retrieve the title that was saved when user tapped submit icon
@@ -157,37 +255,42 @@ public class CategorizationFragment extends Fragment {
 
     /**
      * Retrieves recently-used categories
+     *
      * @return a list containing recent categories
      */
-    protected ArrayList<String> recentCatQuery() {
+    private ArrayList<String> recentCatQuery() {
         ArrayList<String> items = new ArrayList<>();
-
+        Cursor cursor = null;
         try {
-            Cursor cursor = client.query(
+            cursor = client.query(
                     CategoryContentProvider.BASE_URI,
                     Category.Table.ALL_FIELDS,
                     null,
                     new String[]{},
                     Category.Table.COLUMN_LAST_USED + " DESC");
             // fixme add a limit on the original query instead of falling out of the loop?
-            while (cursor.moveToNext() && cursor.getPosition() < SEARCH_CATS_LIMIT) {
+            while (cursor != null && cursor.moveToNext()
+                    && cursor.getPosition() < SEARCH_CATS_LIMIT) {
                 Category cat = Category.fromCursor(cursor);
                 items.add(cat.getName());
             }
-            cursor.close();
+        } catch (RemoteException e) {
-        }
-        catch (RemoteException e) {
             throw new RuntimeException(e);
+        } finally {
+            if (cursor != null) {
+                cursor.close();
+            }
         }
         return items;
     }
 
     /**
-     * Merges nearby categories, categories suggested based on title, and recent categories... without duplicates.
+     * Merges nearby categories, categories suggested based on title, and recent categories...
+     * without duplicates.
+     *
      * @return a list containing merged categories
      */
-    protected ArrayList<String> mergeItems() {
+    ArrayList<String> mergeItems() {
-
         Set<String> mergedItems = new LinkedHashSet<>();
 
         Timber.d("Calling APIs for GPS cats, title cats and recent cats...");
@@ -213,8 +316,9 @@ public class CategorizationFragment extends Fragment {
         Timber.d("Adding title items: %s", titleItems);
         mergedItems.addAll(recentItems);
         Timber.d("Adding recent items: %s", recentItems);
-        
+
-        //Needs to be an ArrayList and not a List unless we want to modify a big portion of preexisting code
+        // Needs to be an ArrayList and not a List unless we want to modify a big portion
+        // of preexisting code
         ArrayList<String> mergedItemsList = new ArrayList<>(mergedItems);
 
         Timber.d("Merged item list: %s", mergedItemsList);
@@ -223,18 +327,20 @@ public class CategorizationFragment extends Fragment {
 
     /**
      * Displays categories found to the user as they type in the search box
+     *
      * @param categories a list of all categories found for the search string
-     * @param filter the search string
+     * @param filter     the search string
      */
-    protected void setCatsAfterAsync(ArrayList<String> categories, String filter) {
+    private void setCatsAfterAsync(ArrayList<String> categories, String filter) {
-
         if (getActivity() != null) {
             ArrayList<CategoryItem> items = new ArrayList<>();
             HashSet<String> existingKeys = new HashSet<>();
-            for (CategoryItem item : categoriesAdapter.getItems()) {
+            int count = categoriesAdapter.getItemCount();
-                if (item.selected) {
+            for (int i = 0; i < count; i++) {
+                CategoryItem item = categoriesAdapter.getItem(i);
+                if (item.isSelected()) {
                     items.add(item);
-                    existingKeys.add(item.name);
+                    existingKeys.add(item.getName());
                 }
             }
             for (String category : categories) {
@@ -243,8 +349,8 @@ public class CategorizationFragment extends Fragment {
                 }
             }
 
-            categoriesAdapter.setItems(items);
+            categoriesAdapter.setCollection(new ListAdapteeCollection<>(items));
-            categoriesAdapter.notifyDataSetInvalidated();
+            categoriesAdapter.notifyDataSetChanged();
             categoriesSearchInProgress.setVisibility(View.GONE);
 
             if (categories.isEmpty()) {
@@ -258,8 +364,7 @@ public class CategorizationFragment extends Fragment {
             } else {
                 categoriesList.smoothScrollToPosition(existingKeys.size());
             }
-        }
+        } else {
-        else {
             Timber.e("Error: Fragment is null");
         }
     }
@@ -272,7 +377,6 @@ public class CategorizationFragment extends Fragment {
      * above Prefix results.
      */
     private void requestSearchResults() {
-
         final CountDownLatch latch = new CountDownLatch(1);
 
         prefixUpdaterSub = new PrefixUpdater(this) {
@@ -282,8 +386,7 @@ public class CategorizationFragment extends Fragment {
                 try {
                     result = super.doInBackground();
                     latch.await();
-                }
+                } catch (InterruptedException e) {
-                catch (InterruptedException e) {
                     Timber.w(e);
                     //Thread.currentThread().interrupt();
                 }
@@ -325,7 +428,6 @@ public class CategorizationFragment extends Fragment {
     }
 
     private void startUpdatingCategoryList() {
-
         if (prefixUpdaterSub != null) {
             prefixUpdaterSub.cancel(true);
         }
@@ -339,238 +441,34 @@ public class CategorizationFragment extends Fragment {
 
     public int getCurrentSelectedCount() {
         int count = 0;
-        for(CategoryItem item: categoriesAdapter.getItems()) {
+        int numberOfItems = categoriesAdapter.getItemCount();
-            if(item.selected) {
+        for (int i = 0; i < numberOfItems; i++) {
+            CategoryItem item = categoriesAdapter.getItem(i);
+            if (item.isSelected()) {
                 count++;
             }
         }
         return count;
     }
 
-    private Category lookupCategory(String name) {
-        Cursor cursor = null;
-        try {
-            cursor = client.query(
-                    CategoryContentProvider.BASE_URI,
-                    Category.Table.ALL_FIELDS,
-                    Category.Table.COLUMN_NAME + "=?",
-                    new String[] {name},
-                    null);
-            if (cursor.moveToFirst()) {
-                return Category.fromCursor(cursor);
-            }
-        } catch (RemoteException e) {
-            // This feels lazy, but to hell with checked exceptions. :)
-            throw new RuntimeException(e);
-        } finally {
-            if ( cursor != null ) {
-                cursor.close();
-            }
-        }
-
-        // Newly used category...
-        Category cat = new Category();
-        cat.setName(name);
-        cat.setLastUsed(new Date());
-        cat.setTimesUsed(0);
-        return cat;
-    }
-
-    private class CategoryCountUpdater extends AsyncTask<Void, Void, Void> {
-
-        private String name;
-
-        public CategoryCountUpdater(String name) {
-            this.name = name;
-        }
-
-        @Override
-        protected Void doInBackground(Void... voids) {
-            Category cat = lookupCategory(name);
-            cat.incTimesUsed();
-
-            cat.setContentProviderClient(client);
-            cat.save();
-
-            return null; // Make the compiler happy.
-        }
-    }
-
-    private void updateCategoryCount(String name) {
-        new CategoryCountUpdater(name).executeOnExecutor(executor);
-    }
-
-    @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        View rootView = inflater.inflate(R.layout.fragment_categorization, null);
-        categoriesList = (ListView) rootView.findViewById(R.id.categoriesListBox);
-        categoriesFilter = (EditText) rootView.findViewById(R.id.categoriesSearchBox);
-        categoriesSearchInProgress = (ProgressBar) rootView.findViewById(R.id.categoriesSearchInProgress);
-        categoriesNotFoundView = (TextView) rootView.findViewById(R.id.categoriesNotFound);
-        categoriesSkip = (TextView) rootView.findViewById(R.id.categoriesExplanation);
-
-        categoriesSkip.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                getActivity().onBackPressed();
-                getActivity().finish();
-            }
-        });
-
-        ArrayList<CategoryItem> items;
-        if(savedInstanceState == null) {
-            items = new ArrayList<>();
-            categoriesCache = new HashMap<>();
-        } else {
-            items = savedInstanceState.getParcelableArrayList("currentCategories");
-            categoriesCache = (HashMap<String, ArrayList<String>>) savedInstanceState.getSerializable("categoriesCache");
-        }
-
-        categoriesAdapter = new CategoriesAdapter(getActivity(), items);
-        categoriesList.setAdapter(categoriesAdapter);
-
-        categoriesList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
-            @Override
-            public void onItemClick(AdapterView<?> adapterView, View view, int index, long id) {
-                CheckedTextView checkedView = (CheckedTextView) view;
-                CategoryItem item = (CategoryItem) adapterView.getAdapter().getItem(index);
-                item.selected = !item.selected;
-                checkedView.setChecked(item.selected);
-                if (item.selected) {
-                    updateCategoryCount(item.name);
-                }
-            }
-        });
-
-        categoriesFilter.addTextChangedListener(textWatcher);
-
-        startUpdatingCategoryList();
-
-        return rootView;
-    }
-
-    @Override
-    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
-        menu.clear();
-        inflater.inflate(R.menu.fragment_categorization, menu);
-    }
-
-    @Override
-    public void onResume() {
-        super.onResume();
-
-        View rootView = getView();
-        if (rootView != null) {
-            rootView.setFocusableInTouchMode(true);
-            rootView.requestFocus();
-            rootView.setOnKeyListener(new View.OnKeyListener() {
-                @Override
-                public boolean onKey(View v, int keyCode, KeyEvent event) {
-                    if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {
-                        backButtonDialog();
-                        return true;
-                    }
-                    return false;
-                }
-            });
-        }
-    }
-
-    @Override
-    public void onDestroyView() {
-        categoriesFilter.removeTextChangedListener(textWatcher);
-        super.onDestroyView();
-    }
-
     public void backButtonDialog() {
-        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
+        new AlertDialog.Builder(getActivity())
-
+                .setMessage("Are you sure you want to go back? The image will not "
-        builder.setMessage("Are you sure you want to go back? The image will not have any categories saved.")
+                        + "have any categories saved.")
-                .setTitle("Warning");
+                .setTitle("Warning")
-        builder.setPositiveButton("No", new DialogInterface.OnClickListener() {
+                .setPositiveButton("No", (dialog, id) -> {
-            @Override
+                    //No need to do anything, user remains on categorization screen
-            public void onClick(DialogInterface dialog, int id) {
+                })
-                //No need to do anything, user remains on categorization screen
+                .setNegativeButton("Yes", (dialog, id) -> getActivity().finish())
-            }
+                .create()
-        });
+                .show();
-        builder.setNegativeButton("Yes", new DialogInterface.OnClickListener() {
-            @Override
-            public void onClick(DialogInterface dialog, int id) {
-                getActivity().finish();
-            }
-        });
-
-        AlertDialog dialog = builder.create();
-        dialog.show();
     }
 
     @Override
-    public void onDestroy() {
+    public void categoryClicked(CategoryItem item) {
-        super.onDestroy();
+        if (item.isSelected()) {
-        client.release();
+            new CategoryCountUpdater(item.getName(), client).executeOnExecutor(executor);
-    }
-
-    @Override
-    public void onSaveInstanceState(Bundle outState) {
-        super.onSaveInstanceState(outState);
-        outState.putParcelableArrayList("currentCategories", categoriesAdapter.getItems());
-        outState.putSerializable("categoriesCache", categoriesCache);
-    }
-
-    @Override
-    public boolean onOptionsItemSelected(MenuItem menuItem) {
-        switch(menuItem.getItemId()) {
-            case R.id.menu_save_categories:
-
-                int numberSelected = 0;
-
-                for(CategoryItem item: categoriesAdapter.getItems()) {
-                    if(item.selected) {
-                        selectedCategories.add(item.name);
-                        numberSelected++;
-                    }
-                }
-
-                //If no categories selected, display warning to user
-                if (numberSelected == 0) {
-                    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
-
-                    builder.setMessage("Images without categories are rarely usable. Are you sure you want to submit without selecting categories?")
-                            .setTitle("No Categories Selected");
-                    builder.setPositiveButton("No, go back", new DialogInterface.OnClickListener() {
-                        @Override
-                        public void onClick(DialogInterface dialog, int id) {
-                            //Exit menuItem so user can select their categories
-                            return;
-                        }
-                    });
-                    builder.setNegativeButton("Yes, submit", new DialogInterface.OnClickListener() {
-                        @Override
-                        public void onClick(DialogInterface dialog, int id) {
-                            //Proceed to submission
-                            onCategoriesSaveHandler.onCategoriesSave(selectedCategories);
-                            return;
-                        }
-                    });
-
-                    AlertDialog dialog = builder.create();
-                    dialog.show();
-                } else {
-                    //Proceed to submission
-                    onCategoriesSaveHandler.onCategoriesSave(selectedCategories);
-                    return true;
-                }
         }
-        return super.onOptionsItemSelected(menuItem);
-    }
-
-    @Override
-    public void onActivityCreated(Bundle savedInstanceState) {
-        super.onActivityCreated(savedInstanceState);
-        setHasOptionsMenu(true);
-        onCategoriesSaveHandler = (OnCategoriesSaveHandler) getActivity();
-        getActivity().setTitle(R.string.categories_activity_title);
-        client = getActivity().getContentResolver().acquireContentProviderClient(CategoryContentProvider.AUTHORITY);
     }
 
     private class CategoryTextWatcher implements TextWatcher {

app/src/main/java/fr/free/nrw/commons/category/Category.java

@@ -26,7 +26,7 @@ public class Category {
         this.name = name;
     }
 
-    public Date getLastUsed() {
+    private Date getLastUsed() {
         // warning: Date objects are mutable.
         return (Date)lastUsed.clone();
     }
@@ -36,11 +36,11 @@ public class Category {
         this.lastUsed = (Date)lastUsed.clone();
     }
 
-    public void touch() {
+    private void touch() {
         lastUsed = new Date();
     }
 
-    public int getTimesUsed() {
+    private int getTimesUsed() {
         return timesUsed;
     }
 
@@ -70,7 +70,7 @@ public class Category {
         }
     }
 
-    public ContentValues toContentValues() {
+    private ContentValues toContentValues() {
         ContentValues cv = new ContentValues();
         cv.put(Table.COLUMN_NAME, getName());
         cv.put(Table.COLUMN_LAST_USED, getLastUsed().getTime());

app/src/main/java/fr/free/nrw/commons/category/CategoryContentProvider.java

@@ -7,6 +7,7 @@ import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 
 import fr.free.nrw.commons.CommonsApplication;
@@ -41,8 +42,10 @@ public class CategoryContentProvider extends ContentProvider {
         return false;
     }
 
+    @SuppressWarnings("ConstantConditions")
     @Override
-    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+    public Cursor query(@NonNull Uri uri, String[] projection, String selection,
+                        String[] selectionArgs, String sortOrder) {
         SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
         queryBuilder.setTables(Category.Table.TABLE_NAME);
 
@@ -53,7 +56,8 @@ public class CategoryContentProvider extends ContentProvider {
 
         switch(uriType) {
             case CATEGORIES:
-                cursor = queryBuilder.query(db, projection, selection, selectionArgs, null, null, sortOrder);
+                cursor = queryBuilder.query(db, projection, selection, selectionArgs,
+                        null, null, sortOrder);
                 break;
             case CATEGORIES_ID:
                 cursor = queryBuilder.query(db,
@@ -75,15 +79,16 @@ public class CategoryContentProvider extends ContentProvider {
     }
 
     @Override
-    public String getType(Uri uri) {
+    public String getType(@NonNull Uri uri) {
         return null;
     }
 
+    @SuppressWarnings("ConstantConditions")
     @Override
-    public Uri insert(Uri uri, ContentValues contentValues) {
+    public Uri insert(@NonNull Uri uri, ContentValues contentValues) {
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = dbOpenHelper.getWritableDatabase();
-        long id = 0;
+        long id;
         switch (uriType) {
             case CATEGORIES:
                 id = sqlDB.insert(Category.Table.TABLE_NAME, null, contentValues);
@@ -96,12 +101,13 @@ public class CategoryContentProvider extends ContentProvider {
     }
 
     @Override
-    public int delete(Uri uri, String s, String[] strings) {
+    public int delete(@NonNull Uri uri, String s, String[] strings) {
         return 0;
     }
 
+    @SuppressWarnings("ConstantConditions")
     @Override
-    public int bulkInsert(Uri uri, ContentValues[] values) {
+    public int bulkInsert(@NonNull Uri uri, @NonNull ContentValues[] values) {
         Timber.d("Hello, bulk insert! (CategoryContentProvider)");
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = dbOpenHelper.getWritableDatabase();
@@ -122,8 +128,10 @@ public class CategoryContentProvider extends ContentProvider {
         return values.length;
     }
 
+    @SuppressWarnings("ConstantConditions")
     @Override
-    public int update(Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
+    public int update(@NonNull Uri uri, ContentValues contentValues, String selection,
+                      String[] selectionArgs) {
         /*
         SQL Injection warnings: First, note that we're not exposing this to the outside world (exported="false")
         Even then, we should make sure to sanitize all user input appropriately. Input that passes through ContentValues
@@ -133,7 +141,7 @@ public class CategoryContentProvider extends ContentProvider {
          */
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = dbOpenHelper.getWritableDatabase();
-        int rowsUpdated = 0;
+        int rowsUpdated;
         switch (uriType) {
             case CATEGORIES_ID:
                 int id = Integer.valueOf(uri.getLastPathSegment());
@@ -144,7 +152,8 @@ public class CategoryContentProvider extends ContentProvider {
                             Category.Table.COLUMN_ID + " = ?",
                             new String[] { String.valueOf(id) } );
                 } else {
-                    throw new IllegalArgumentException("Parameter `selection` should be empty when updating an ID");
+                    throw new IllegalArgumentException(
+                            "Parameter `selection` should be empty when updating an ID");
                 }
                 break;
             default:

app/src/main/java/fr/free/nrw/commons/category/CategoryCountUpdater.java

@@ -0,0 +1,59 @@
+package fr.free.nrw.commons.category;
+
+import android.content.ContentProviderClient;
+import android.database.Cursor;
+import android.os.AsyncTask;
+import android.os.RemoteException;
+
+import java.util.Date;
+
+class CategoryCountUpdater extends AsyncTask<Void, Void, Void> {
+
+    private final String name;
+    private final ContentProviderClient client;
+
+    CategoryCountUpdater(String name, ContentProviderClient client) {
+        this.name = name;
+        this.client = client;
+    }
+
+    @Override
+    protected Void doInBackground(Void... voids) {
+        Category cat = lookupCategory(name);
+        cat.incTimesUsed();
+
+        cat.setContentProviderClient(client);
+        cat.save();
+
+        return null; // Make the compiler happy.
+    }
+
+    private Category lookupCategory(String name) {
+        Cursor cursor = null;
+        try {
+            cursor = client.query(
+                    CategoryContentProvider.BASE_URI,
+                    Category.Table.ALL_FIELDS,
+                    Category.Table.COLUMN_NAME + "=?",
+                    new String[]{name},
+                    null);
+            if (cursor != null && cursor.moveToFirst()) {
+                return Category.fromCursor(cursor);
+            }
+        } catch (RemoteException e) {
+            // This feels lazy, but to hell with checked exceptions. :)
+            throw new RuntimeException(e);
+        } finally {
+            if (cursor != null) {
+                cursor.close();
+            }
+        }
+
+        // Newly used category...
+        Category cat = new Category();
+        cat.setName(name);
+        cat.setLastUsed(new Date());
+        cat.setTimesUsed(0);
+        return cat;
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/CategoryItem.java

@@ -0,0 +1,54 @@
+package fr.free.nrw.commons.category;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+
+class CategoryItem implements Parcelable {
+    private final String name;
+    private boolean selected;
+
+    public static Creator<CategoryItem> CREATOR = new Creator<CategoryItem>() {
+        @Override
+        public CategoryItem createFromParcel(Parcel parcel) {
+            return new CategoryItem(parcel);
+        }
+
+        @Override
+        public CategoryItem[] newArray(int i) {
+            return new CategoryItem[0];
+        }
+    };
+
+    CategoryItem(String name, boolean selected) {
+        this.name = name;
+        this.selected = selected;
+    }
+
+    private CategoryItem(Parcel in) {
+        name = in.readString();
+        selected = in.readInt() == 1;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public boolean isSelected() {
+        return selected;
+    }
+
+    public void setSelected(boolean selected) {
+        this.selected = selected;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel parcel, int flags) {
+        parcel.writeString(name);
+        parcel.writeInt(selected ? 1 : 0);
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/MethodAUpdater.java

@@ -13,6 +13,8 @@ import fr.free.nrw.commons.CommonsApplication;
 import fr.free.nrw.commons.mwapi.MediaWikiApi;
 import timber.log.Timber;
 
+import static fr.free.nrw.commons.category.CategorizationFragment.SEARCH_CATS_LIMIT;
+
 /**
  * Sends asynchronous queries to the Commons MediaWiki API to retrieve categories that are close to
  * the keyword typed in by the user. The 'srsearch' action-specific parameter is used for this
@@ -20,8 +22,8 @@ import timber.log.Timber;
  */
 class MethodAUpdater extends AsyncTask<Void, Void, List<String>> {
 
+    private final CategorizationFragment catFragment;
     private String filter;
-    private CategorizationFragment catFragment;
 
     MethodAUpdater(CategorizationFragment catFragment) {
         this.catFragment = catFragment;
@@ -84,7 +86,7 @@ class MethodAUpdater extends AsyncTask<Void, Void, List<String>> {
 
         //URL https://commons.wikimedia.org/w/api.php?action=query&format=xml&list=search&srwhat=text&srenablerewrites=1&srnamespace=14&srlimit=10&srsearch=
         try {
-            categories = api.searchCategories(CategorizationFragment.SEARCH_CATS_LIMIT, filter);
+            categories = api.searchCategories(SEARCH_CATS_LIMIT, filter);
             Timber.d("Method A URL filter %s", categories);
         } catch (IOException e) {
             Timber.e(e, "IO Exception: ");

app/src/main/java/fr/free/nrw/commons/category/OnCategoriesSaveHandler.java

@@ -0,0 +1,7 @@
+package fr.free.nrw.commons.category;
+
+import java.util.ArrayList;
+
+public interface OnCategoriesSaveHandler {
+    void onCategoriesSave(ArrayList<String> categories);
+}

app/src/main/java/fr/free/nrw/commons/category/PrefixUpdater.java

@@ -7,6 +7,7 @@ import android.view.View;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 
@@ -14,18 +15,20 @@ import fr.free.nrw.commons.CommonsApplication;
 import fr.free.nrw.commons.mwapi.MediaWikiApi;
 import timber.log.Timber;
 
+import static fr.free.nrw.commons.category.CategorizationFragment.SEARCH_CATS_LIMIT;
+
 /**
  * Sends asynchronous queries to the Commons MediaWiki API to retrieve categories that share the
  * same prefix as the keyword typed in by the user. The 'acprefix' action-specific parameter is used
  * for this purpose. This class should be subclassed in CategorizationFragment.java to aggregate
  * the results.
  */
-public class PrefixUpdater extends AsyncTask<Void, Void, List<String>> {
+class PrefixUpdater extends AsyncTask<Void, Void, List<String>> {
 
+    private final CategorizationFragment catFragment;
     private String filter;
-    private CategorizationFragment catFragment;
 
-    public PrefixUpdater(CategorizationFragment catFragment) {
+    PrefixUpdater(CategorizationFragment catFragment) {
         this.catFragment = catFragment;
     }
 
@@ -90,8 +93,9 @@ public class PrefixUpdater extends AsyncTask<Void, Void, List<String>> {
         }
 
         //if user types in something that is in cache, return cached category
-        if (catFragment.categoriesCache.containsKey(filter)) {
+        HashMap<String, ArrayList<String>> categoriesCache = catFragment.getCategoriesCache();
-            ArrayList<String> cachedItems = new ArrayList<>(catFragment.categoriesCache.get(filter));
+        if (categoriesCache.containsKey(filter)) {
+            ArrayList<String> cachedItems = new ArrayList<>(categoriesCache.get(filter));
             Timber.d("Found cache items, waiting for filter");
             return new ArrayList<>(filterIrrelevantResults(cachedItems));
         }
@@ -101,7 +105,7 @@ public class PrefixUpdater extends AsyncTask<Void, Void, List<String>> {
         MediaWikiApi api = CommonsApplication.getInstance().getMWApi();
         List<String> categories = new ArrayList<>();
         try {
-            categories = api.allCategories(CategorizationFragment.SEARCH_CATS_LIMIT, this.filter);
+            categories = api.allCategories(SEARCH_CATS_LIMIT, this.filter);
             Timber.d("Prefix URL filter %s", categories);
         } catch (IOException e) {
             Timber.e(e, "IO Exception: ");

app/src/main/java/fr/free/nrw/commons/category/TitleCategories.java

@@ -19,17 +19,12 @@ class TitleCategories extends AsyncTask<Void, Void, List<String>> {
 
     private final static int SEARCH_CATS_LIMIT = 25;
 
-    private String title;
+    private final String title;
 
     TitleCategories(String title) {
         this.title = title;
     }
 
-    @Override
-    protected void onPreExecute() {
-        super.onPreExecute();
-    }
-
     @Override
     protected List<String> doInBackground(Void... voids) {
 

app/src/main/java/fr/free/nrw/commons/concurrency/BackgroundPoolExceptionHandler.java

@@ -9,11 +9,8 @@ public class BackgroundPoolExceptionHandler implements ExceptionHandler {
     public void onException(@NonNull final Throwable t) {
         //Crash for debug build
         if (BuildConfig.DEBUG) {
-            Thread thread = new Thread(new Runnable() {
+            Thread thread = new Thread(() -> {
-                @Override
+                throw new RuntimeException(t);
-                public void run() {
-                    throw new RuntimeException(t);
-                }
             });
             thread.start();
         }

app/src/main/java/fr/free/nrw/commons/concurrency/ThreadFactoryMaker.java

@@ -11,17 +11,13 @@ class ThreadFactoryMaker {
             private int count = 0;
 
             @Override
-            public Thread newThread(final Runnable runnable) {
+            public Thread newThread(@NonNull final Runnable runnable) {
                 count++;
-                Runnable wrapperRunnable = new Runnable() {
+                Runnable wrapperRunnable = () -> {
-                    @Override
+                    Process.setThreadPriority(priority);
-                    public void run() {
+                    runnable.run();
-                        Process.setThreadPriority(priority);
-                        runnable.run();
-                    }
                 };
-                Thread t = new Thread(wrapperRunnable, String.format("%s-%s", name, count));
+                return new Thread(wrapperRunnable, String.format("%s-%s", name, count));
-                return t;
             }
         };
     }

app/src/main/java/fr/free/nrw/commons/concurrency/ThreadPoolExecutorService.java

@@ -39,7 +39,7 @@ public class ThreadPoolExecutorService implements Executor {
     }
 
     @Override
-    public void execute(Runnable command) {
+    public void execute(@NonNull Runnable command) {
         backgroundPool.execute(command);
     }
 

app/src/main/java/fr/free/nrw/commons/contributions/ContributionsActivity.java

@@ -3,11 +3,13 @@ package fr.free.nrw.commons.contributions;
 import android.content.ComponentName;
 import android.content.ContentResolver;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.content.SharedPreferences;
 import android.database.Cursor;
 import android.database.DataSetObserver;
+import android.net.Uri;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.preference.PreferenceManager;
@@ -17,6 +19,7 @@ import android.support.v4.app.LoaderManager;
 import android.support.v4.content.CursorLoader;
 import android.support.v4.content.Loader;
 import android.support.v4.widget.CursorAdapter;
+import android.support.v7.app.AlertDialog;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -27,7 +30,10 @@ import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
+import java.util.Date;
 
 import butterknife.ButterKnife;
 import fr.free.nrw.commons.CommonsApplication;
@@ -110,6 +116,12 @@ public  class       ContributionsActivity
         super.onPause();
     }
 
+    @Override
+    protected void onStart() {
+        super.onStart();
+        displayFeedbackPopup();
+    }
+
     @Override
     protected void onAuthCookieAcquired(String authCookie) {
         // Do a sync everytime we get here!
@@ -342,4 +354,56 @@ public  class       ContributionsActivity
         Intent contributionsIntent = new Intent(context, ContributionsActivity.class);
         context.startActivity(contributionsIntent);
     }
+
+    private void displayFeedbackPopup() {
+
+        Date popupMessageEndDate = null;
+        try {
+            String validUntil = "23/08/2017";
+            SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
+            popupMessageEndDate = sdf.parse(validUntil);
+        } catch (ParseException e) {
+            e.printStackTrace();
+        }
+
+        final SharedPreferences prefs =  PreferenceManager.getDefaultSharedPreferences(
+                CommonsApplication.getInstance());
+
+        // boolean to save users request about displaying popup
+        boolean displayFeedbackPopup = prefs.getBoolean("display_feedbak_popup", true);
+
+        // boolean to recognize is application re-started. Will be used for "remind me later" option
+        int appStartCounter = prefs.getInt("app_start_counter" ,0);
+
+        // if time is valid and shared pref says display
+        if (new Date().before(popupMessageEndDate) && displayFeedbackPopup && (appStartCounter == 4)) {
+
+            new AlertDialog.Builder(this)
+            .setTitle(getResources().getString(R.string.feedback_popup_title))
+            .setMessage(getResources().getString(R.string.feedback_popup_description))
+            .setPositiveButton(getResources().getString(R.string.feedback_popup_accept),
+                    new DialogInterface.OnClickListener() {
+                        public void onClick(DialogInterface dialog, int which) {
+                            // Go to the page
+                            Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri
+                                    .parse(getResources()
+                                    .getString(R.string.feedback_page_url)));
+                            startActivity(browserIntent);
+                            // No need to dislay this window to the user again.
+                            prefs.edit().putBoolean("display_feedbak_popup" , false).commit();
+                            dialog.dismiss();
+                        }
+                    })
+            .setNegativeButton(getResources().getString(R.string.feedback_popup_decline),
+                    new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            // Dismiss the dialog and not to show it later
+                            prefs.edit().putBoolean("display_feedbak_popup", false).commit();
+                            dialog.dismiss();
+                        }
+                    })
+            .create().show();
+        }
+    }
 }

app/src/main/java/fr/free/nrw/commons/contributions/ContributionsContentProvider.java

@@ -7,6 +7,7 @@ import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 
 import fr.free.nrw.commons.CommonsApplication;
@@ -38,7 +39,7 @@ public class ContributionsContentProvider extends ContentProvider{
     }
 
     @Override
-    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+    public Cursor query(@NonNull Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
         SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
         queryBuilder.setTables(Contribution.Table.TABLE_NAME);
 
@@ -71,12 +72,12 @@ public class ContributionsContentProvider extends ContentProvider{
     }
 
     @Override
-    public String getType(Uri uri) {
+    public String getType(@NonNull Uri uri) {
         return null;
     }
 
     @Override
-    public Uri insert(Uri uri, ContentValues contentValues) {
+    public Uri insert(@NonNull Uri uri, ContentValues contentValues) {
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = CommonsApplication.getInstance().getDBOpenHelper().getWritableDatabase();
         long id = 0;
@@ -92,7 +93,7 @@ public class ContributionsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int delete(Uri uri, String s, String[] strings) {
+    public int delete(@NonNull Uri uri, String s, String[] strings) {
         int rows = 0;
         int uriType = uriMatcher.match(uri);
 
@@ -114,7 +115,7 @@ public class ContributionsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int bulkInsert(Uri uri, ContentValues[] values) {
+    public int bulkInsert(@NonNull Uri uri, @NonNull ContentValues[] values) {
         Timber.d("Hello, bulk insert! (ContributionsContentProvider)");
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = CommonsApplication.getInstance().getDBOpenHelper().getWritableDatabase();
@@ -136,7 +137,7 @@ public class ContributionsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int update(Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
+    public int update(@NonNull Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
         /*
         SQL Injection warnings: First, note that we're not exposing this to the outside world (exported="false")
         Even then, we should make sure to sanitize all user input appropriately. Input that passes through ContentValues

app/src/main/java/fr/free/nrw/commons/contributions/ContributionsListFragment.java

@@ -8,6 +8,7 @@ import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.Fragment;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AlertDialog;
@@ -29,6 +30,7 @@ import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.nearby.NearbyActivity;
 import timber.log.Timber;
 
+import static android.Manifest.permission.READ_EXTERNAL_STORAGE;
 import static android.app.Activity.RESULT_OK;
 
 public class ContributionsListFragment extends Fragment {
@@ -110,11 +112,11 @@ public class ContributionsListFragment extends Fragment {
 
                     // Here, thisActivity is the current activity
                     if (ContextCompat.checkSelfPermission(getActivity(),
-                            Manifest.permission.READ_EXTERNAL_STORAGE)
+                            READ_EXTERNAL_STORAGE)
                             != PackageManager.PERMISSION_GRANTED) {
 
                         // Should we show an explanation?
-                        if (shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE)) {
+                        if (shouldShowRequestPermissionRationale(READ_EXTERNAL_STORAGE)) {
 
                             // Show an explanation to the user *asynchronously* -- don't block
                             // this thread waiting for the user's response! After the user
@@ -122,15 +124,9 @@ public class ContributionsListFragment extends Fragment {
 
                             new AlertDialog.Builder(getActivity())
                                     .setMessage(getString(R.string.storage_permission_rationale))
-                                    .setPositiveButton("OK", new DialogInterface.OnClickListener() {
+                                    .setPositiveButton("OK", (dialog, which) -> {
-                                        @Override
+                                        requestPermissions(new String[]{READ_EXTERNAL_STORAGE}, 1);
-                                        public void onClick(DialogInterface dialog, int which) {
+                                        dialog.dismiss();
-
-                                            requestPermissions(
-                                                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
-                                                    1);
-                                            dialog.dismiss();
-                                        }
                                     })
                                     .setNegativeButton("Cancel", null)
                                     .create()
@@ -140,7 +136,7 @@ public class ContributionsListFragment extends Fragment {
 
                             // No explanation needed, we can request the permission.
 
-                            requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
+                            requestPermissions(new String[]{READ_EXTERNAL_STORAGE},
                                     1);
 
                             // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
@@ -167,7 +163,7 @@ public class ContributionsListFragment extends Fragment {
     }
 
     @Override
-    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 
         Timber.d("onRequestPermissionsResult: req code = " + " perm = " + permissions + " grant =" + grantResults);
 

app/src/main/java/fr/free/nrw/commons/contributions/UploadCountClient.java

@@ -14,10 +14,10 @@ import fr.free.nrw.commons.concurrency.BackgroundPoolExceptionHandler;
 import fr.free.nrw.commons.concurrency.ThreadPoolExecutorService;
 import timber.log.Timber;
 
-public class UploadCountClient {
+class UploadCountClient {
     private ThreadPoolExecutorService threadPoolExecutor;
 
-    public UploadCountClient() {
+    UploadCountClient() {
         threadPoolExecutor = new ThreadPoolExecutorService.Builder("bg-pool")
                 .setPoolSize(Runtime.getRuntime().availableProcessors())
                 .setExceptionHandler(new BackgroundPoolExceptionHandler())
@@ -27,29 +27,26 @@ public class UploadCountClient {
     private static final String UPLOAD_COUNT_URL_TEMPLATE =
             "https://tools.wmflabs.org/urbanecmbot/uploadsbyuser/uploadsbyuser.py?user=%s";
 
-    public ListenableFuture<Integer> getUploadCount(final String userName) {
+    ListenableFuture<Integer> getUploadCount(final String userName) {
         final SettableFuture<Integer> future = SettableFuture.create();
-        threadPoolExecutor.schedule(new Runnable() {
+        threadPoolExecutor.schedule(() -> {
-            @Override
+            URL url;
-            public void run() {
+            try {
-                URL url;
+                url = new URL(String.format(Locale.ENGLISH, UPLOAD_COUNT_URL_TEMPLATE,
+                        new PageTitle(userName).getText()));
+                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                 try {
-                    url = new URL(String.format(Locale.ENGLISH, UPLOAD_COUNT_URL_TEMPLATE,
+                    BufferedReader bufferedReader = new BufferedReader(new
-                            new PageTitle(userName).getText()));
+                            InputStreamReader(urlConnection.getInputStream()));
-                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
+                    String uploadCount = bufferedReader.readLine();
-                    try {
+                    bufferedReader.close();
-                        BufferedReader bufferedReader = new BufferedReader(new
+                    future.set(Integer.parseInt(uploadCount));
-                                InputStreamReader(urlConnection.getInputStream()));
+                } finally {
-                        String uploadCount = bufferedReader.readLine();
+                    urlConnection.disconnect();
-                        bufferedReader.close();
-                        future.set(Integer.parseInt(uploadCount));
-                    } finally {
-                        urlConnection.disconnect();
-                    }
-                } catch (Exception e) {
-                    Timber.e("Error getting upload count Error", e);
-                    future.setException(e);
                 }
+            } catch (Exception e) {
+                Timber.e("Error getting upload count Error", e);
+                future.setException(e);
             }
         });
         return future;

app/src/main/java/fr/free/nrw/commons/media/MediaDetailFragment.java

@@ -119,12 +119,7 @@ public class MediaDetailFragment extends Fragment {
         licenseList = new LicenseList(getActivity());
 
         // Progressively darken the image in the background when we scroll detail pane up
-        scrollListener = new ViewTreeObserver.OnScrollChangedListener() {
+        scrollListener = this::updateTheDarkness;
-            @Override
-            public void onScrollChanged() {
-                updateTheDarkness();
-            }
-        };
         view.getViewTreeObserver().addOnScrollChangedListener(scrollListener);
 
         // Layout layoutListener to size the spacer item relative to the available space.
@@ -280,15 +275,12 @@ public class MediaDetailFragment extends Fragment {
 
         textView.setText(catName);
         if (categoriesLoaded && categoriesPresent) {
-            textView.setOnClickListener(new View.OnClickListener() {
+            textView.setOnClickListener(view -> {
-                @Override
+                String selectedCategoryTitle = "Category:" + catName;
-                public void onClick(View view) {
+                Intent viewIntent = new Intent();
-                    String selectedCategoryTitle = "Category:" + catName;
+                viewIntent.setAction(Intent.ACTION_VIEW);
-                    Intent viewIntent = new Intent();
+                viewIntent.setData(new PageTitle(selectedCategoryTitle).getCanonicalUri());
-                    viewIntent.setAction(Intent.ACTION_VIEW);
+                startActivity(viewIntent);
-                    viewIntent.setData(new PageTitle(selectedCategoryTitle).getCanonicalUri());
-                    startActivity(viewIntent);
-                }
             });
         }
         return item;

app/src/main/java/fr/free/nrw/commons/media/MediaDetailPagerFragment.java

@@ -72,12 +72,7 @@ public class MediaDetailPagerFragment extends Fragment implements ViewPager.OnPa
         public Fragment getItem(int i) {
             if (i == 0) {
                 // See bug https://code.google.com/p/android/issues/detail?id=27526
-                pager.postDelayed(new Runnable() {
+                pager.postDelayed(() -> getActivity().supportInvalidateOptionsMenu(), 5);
-                    @Override
-                    public void run() {
-                        getActivity().supportInvalidateOptionsMenu();
-                    }
-                }, 5);
             }
             return MediaDetailFragment.forMedia(i, editable);
         }
@@ -100,14 +95,11 @@ public class MediaDetailPagerFragment extends Fragment implements ViewPager.OnPa
             final int pageNumber = savedInstanceState.getInt("current-page");
             // Adapter doesn't seem to be loading immediately.
             // Dear God, please forgive us for our sins
-            view.postDelayed(new Runnable() {
+            view.postDelayed(() -> {
-                @Override
+                pager.setAdapter(adapter);
-                public void run() {
+                pager.setCurrentItem(pageNumber, false);
-                    pager.setAdapter(adapter);
+                getActivity().supportInvalidateOptionsMenu();
-                    pager.setCurrentItem(pageNumber, false);
+                adapter.notifyDataSetChanged();
-                    getActivity().supportInvalidateOptionsMenu();
-                    adapter.notifyDataSetChanged();
-                }
             }, 100);
         } else {
             pager.setAdapter(adapter);
@@ -196,13 +188,8 @@ public class MediaDetailPagerFragment extends Fragment implements ViewPager.OnPa
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !(ContextCompat.checkSelfPermission(getContext(), Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED)) {
             Snackbar.make(getView(), R.string.storage_permission_rationale,
                     Snackbar.LENGTH_INDEFINITE)
-                    .setAction(R.string.ok, new View.OnClickListener() {
+                    .setAction(R.string.ok, view -> ActivityCompat.requestPermissions(getActivity(),
-                        @Override
+                            new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1)).show();
-                        public void onClick(View view) {
-                            ActivityCompat.requestPermissions(getActivity(),
-                                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
-                        }
-                    }).show();
         } else {
             final DownloadManager manager = (DownloadManager)getActivity().getSystemService(Context.DOWNLOAD_SERVICE);
             manager.enqueue(req);

app/src/main/java/fr/free/nrw/commons/modifications/ModificationsContentProvider.java

@@ -7,6 +7,7 @@ import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 
 import fr.free.nrw.commons.CommonsApplication;
@@ -39,7 +40,7 @@ public class ModificationsContentProvider extends ContentProvider{
     }
 
     @Override
-    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+    public Cursor query(@NonNull Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
         SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
         queryBuilder.setTables(ModifierSequence.Table.TABLE_NAME);
 
@@ -61,12 +62,12 @@ public class ModificationsContentProvider extends ContentProvider{
     }
 
     @Override
-    public String getType(Uri uri) {
+    public String getType(@NonNull Uri uri) {
         return null;
     }
 
     @Override
-    public Uri insert(Uri uri, ContentValues contentValues) {
+    public Uri insert(@NonNull Uri uri, ContentValues contentValues) {
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = CommonsApplication.getInstance().getDBOpenHelper().getWritableDatabase();
         long id = 0;
@@ -82,7 +83,7 @@ public class ModificationsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int delete(Uri uri, String s, String[] strings) {
+    public int delete(@NonNull Uri uri, String s, String[] strings) {
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = CommonsApplication.getInstance().getDBOpenHelper().getWritableDatabase();
         switch (uriType) {
@@ -99,7 +100,7 @@ public class ModificationsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int bulkInsert(Uri uri, ContentValues[] values) {
+    public int bulkInsert(@NonNull Uri uri, @NonNull ContentValues[] values) {
         Timber.d("Hello, bulk insert! (ModificationsContentProvider)");
         int uriType = uriMatcher.match(uri);
         SQLiteDatabase sqlDB = CommonsApplication.getInstance().getDBOpenHelper().getWritableDatabase();
@@ -121,7 +122,7 @@ public class ModificationsContentProvider extends ContentProvider{
     }
 
     @Override
-    public int update(Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
+    public int update(@NonNull Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
         /*
         SQL Injection warnings: First, note that we're not exposing this to the outside world (exported="false")
         Even then, we should make sure to sanitize all user input appropriately. Input that passes through ContentValues

app/src/main/java/fr/free/nrw/commons/mwapi/ApacheHttpClientMediaWikiApi.java

@@ -351,12 +351,7 @@ public class ApacheHttpClientMediaWikiApi implements MediaWikiApi {
     @Override
     @NonNull
     public UploadResult uploadFile(String filename, InputStream file, long dataLength, String pageContents, String editSummary, final ProgressListener progressListener) throws IOException {
-        ApiResult result = api.upload(filename, file, dataLength, pageContents, editSummary, new in.yuvi.http.fluent.ProgressListener() {
+        ApiResult result = api.upload(filename, file, dataLength, pageContents, editSummary, progressListener::onProgress);
-            @Override
-            public void onProgress(long transferred, long total) {
-                progressListener.onProgress(transferred, total);
-            }
-        });
 
         Log.e("WTF", "Result: "+result.toString());
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyActivity.java

@@ -2,7 +2,6 @@ package fr.free.nrw.commons.nearby;
 
 import android.Manifest;
 import android.content.Context;
-import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.location.LocationManager;
@@ -41,7 +40,8 @@ import timber.log.Timber;
 
 public class NearbyActivity extends NavigationBaseActivity {
 
-    @BindView(R.id.progressBar) ProgressBar progressBar;
+    @BindView(R.id.progressBar)
+    ProgressBar progressBar;
     private boolean isMapViewActive = false;
     private static final int LOCATION_REQUEST = 1;
 
@@ -115,15 +115,11 @@ public class NearbyActivity extends NavigationBaseActivity {
 
                         new AlertDialog.Builder(this)
                                 .setMessage(getString(R.string.location_permission_rationale))
-                                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
+                                .setPositiveButton("OK", (dialog, which) -> {
-                                    @Override
+                                    ActivityCompat.requestPermissions(NearbyActivity.this,
-                                    public void onClick(DialogInterface dialog, int which) {
+                                            new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
-
+                                            LOCATION_REQUEST);
-                                        ActivityCompat.requestPermissions(NearbyActivity.this,
+                                    dialog.dismiss();
-                                                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
-                                                LOCATION_REQUEST);
-                                        dialog.dismiss();
-                                    }
                                 })
                                 .setNegativeButton("Cancel", null)
                                 .create()
@@ -175,26 +171,19 @@ public class NearbyActivity extends NavigationBaseActivity {
         LocationManager manager = (LocationManager) getSystemService(LOCATION_SERVICE);
         if (!manager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
             Timber.d("GPS is not enabled");
-            AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
+            new AlertDialog.Builder(this)
-            alertDialogBuilder.setMessage(R.string.gps_disabled)
+                    .setMessage(R.string.gps_disabled)
                     .setCancelable(false)
                     .setPositiveButton(R.string.enable_gps,
-                            new DialogInterface.OnClickListener() {
+                            (dialog, id) -> {
-                                public void onClick(DialogInterface dialog, int id) {
+                                Intent callGPSSettingIntent = new Intent(
-                                    Intent callGPSSettingIntent = new Intent(
+                                        android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
-                                            android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
+                                Timber.d("Loaded settings page");
-                                    Timber.d("Loaded settings page");
+                                startActivityForResult(callGPSSettingIntent, 1);
-                                    startActivityForResult(callGPSSettingIntent, 1);
+                            })
-                                }
+                    .setNegativeButton(R.string.menu_cancel_upload, (dialog, id) -> dialog.cancel())
-                            });
+                    .create()
-            alertDialogBuilder.setNegativeButton(R.string.menu_cancel_upload,
+                    .show();
-                    new DialogInterface.OnClickListener() {
-                        public void onClick(DialogInterface dialog, int id) {
-                            dialog.cancel();
-                        }
-                    });
-            AlertDialog alert = alertDialogBuilder.create();
-            alert.show();
         } else {
             Timber.d("GPS is enabled");
         }
@@ -257,7 +246,7 @@ public class NearbyActivity extends NavigationBaseActivity {
 
         private final Context mContext;
 
-        private NearbyAsyncTask (Context context) {
+        private NearbyAsyncTask(Context context) {
             mContext = context;
         }
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyAdapterFactory.java

@@ -1,5 +1,7 @@
 package fr.free.nrw.commons.nearby;
 
+import android.support.annotation.NonNull;
+
 import com.pedrogomez.renderers.ListAdapteeCollection;
 import com.pedrogomez.renderers.RVRendererAdapter;
 import com.pedrogomez.renderers.RendererBuilder;
@@ -10,7 +12,7 @@ import java.util.List;
 class NearbyAdapterFactory {
     private PlaceRenderer.PlaceClickedListener listener;
 
-    NearbyAdapterFactory(PlaceRenderer.PlaceClickedListener listener) {
+    NearbyAdapterFactory(@NonNull PlaceRenderer.PlaceClickedListener listener) {
         this.listener = listener;
     }
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyController.java

@@ -52,13 +52,10 @@ public class NearbyController {
                 distances.put(place, computeDistanceBetween(place.location, curLatLng));
             }
             Collections.sort(places,
-                    new Comparator<Place>() {
+                    (lhs, rhs) -> {
-                        @Override
+                        double lhsDistance = distances.get(lhs);
-                        public int compare(Place lhs, Place rhs) {
+                        double rhsDistance = distances.get(rhs);
-                            double lhsDistance = distances.get(lhs);
+                        return (int) (lhsDistance - rhsDistance);
-                            double rhsDistance = distances.get(rhs);
-                            return (int) (lhsDistance - rhsDistance);
-                        }
                     }
             );
         }

app/src/main/java/fr/free/nrw/commons/nearby/NearbyInfoDialog.java

@@ -63,15 +63,10 @@ public class NearbyInfoDialog extends OverlayDialog {
 
         overflowButton.setVisibility(showMenu() ? View.VISIBLE : View.GONE);
 
-        overflowButton.setOnClickListener(new View.OnClickListener() {
+        overflowButton.setOnClickListener(this::popupMenuListener);
-            @Override
-            public void onClick(View v) {
-                popupMenuListener();
-            }
-        });
     }
 
-    private void popupMenuListener() {
+    private void popupMenuListener(View v) {
         PopupMenu popupMenu = new PopupMenu(getActivity(), overflowButton);
         popupMenu.inflate(R.menu.nearby_info_dialog_options);
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyListFragment.java

@@ -48,12 +48,7 @@ public class NearbyListFragment extends Fragment {
         View view = inflater.inflate(R.layout.fragment_nearby, container, false);
         recyclerView = (RecyclerView) view.findViewById(R.id.listView);
         recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-        adapterFactory = new NearbyAdapterFactory(new PlaceRenderer.PlaceClickedListener() {
+        adapterFactory = new NearbyAdapterFactory(place -> NearbyInfoDialog.showYourself(getActivity(), place));
-            @Override
-            public void placeClicked(Place place) {
-                NearbyInfoDialog.showYourself(getActivity(), place);
-            }
-        });
         return view;
     }
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyMapFragment.java

@@ -88,25 +88,19 @@ public class NearbyMapFragment extends android.support.v4.app.Fragment {
         // create map
         mapView = new MapView(getActivity(), options);
         mapView.onCreate(savedInstanceState);
-        mapView.getMapAsync(new OnMapReadyCallback() {
+        mapView.getMapAsync(mapboxMap -> {
-            @Override
+            mapboxMap.addMarkers(baseMarkerOptions);
-            public void onMapReady(MapboxMap mapboxMap) {
-                mapboxMap.addMarkers(baseMarkerOptions);
 
-                mapboxMap.setOnMarkerClickListener(new MapboxMap.OnMarkerClickListener() {
+            mapboxMap.setOnMarkerClickListener(marker -> {
-                    @Override
+                if (marker instanceof NearbyMarker) {
-                    public boolean onMarkerClick(@NonNull Marker marker) {
+                    NearbyMarker nearbyMarker = (NearbyMarker) marker;
-                        if (marker instanceof NearbyMarker) {
+                    Place place = nearbyMarker.getNearbyBaseMarker().getPlace();
-                            NearbyMarker nearbyMarker = (NearbyMarker) marker;
+                    NearbyInfoDialog.showYourself(getActivity(), place);
-                            Place place = nearbyMarker.getNearbyBaseMarker().getPlace();
+                }
-                            NearbyInfoDialog.showYourself(getActivity(), place);
+                return false;
-                        }
+            });
-                        return false;
-                    }
-                });
 
-                addCurrentLocationMarker(mapboxMap);
+            addCurrentLocationMarker(mapboxMap);
-            }
         });
         if (PreferenceManager.getDefaultSharedPreferences(getActivity()).getBoolean("theme",true)) {
             mapView.setStyleUrl(getResources().getString(R.string.map_theme_dark));

app/src/main/java/fr/free/nrw/commons/nearby/PlaceRenderer.java

@@ -1,5 +1,6 @@
 package fr.free.nrw.commons.nearby;
 
+import android.support.annotation.NonNull;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -19,7 +20,7 @@ class PlaceRenderer extends Renderer<Place> {
     @BindView(R.id.icon) ImageView icon;
     private final PlaceClickedListener listener;
 
-    PlaceRenderer(PlaceClickedListener listener) {
+    PlaceRenderer(@NonNull PlaceClickedListener listener) {
         this.listener = listener;
     }
 
@@ -35,14 +36,7 @@ class PlaceRenderer extends Renderer<Place> {
 
     @Override
     protected void hookListeners(View view) {
-        view.setOnClickListener(new View.OnClickListener() {
+        view.setOnClickListener(v -> listener.placeClicked(getContent()));
-            @Override
-            public void onClick(View v) {
-                if (listener != null) {
-                    listener.placeClicked(getContent());
-                }
-            }
-        });
     }
 
     @Override

app/src/main/java/fr/free/nrw/commons/settings/SettingsFragment.java

@@ -28,21 +28,15 @@ public class SettingsFragment extends PreferenceFragment {
         licensePreference.setSummary(getString(Utils.licenseNameFor(licensePreference.getValue())));
 
         // Keep summary updated when changing value
-        licensePreference.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+        licensePreference.setOnPreferenceChangeListener((preference, newValue) -> {
-            @Override
+            preference.setSummary(getString(Utils.licenseNameFor((String) newValue)));
-            public boolean onPreferenceChange(Preference preference, Object newValue) {
+            return true;
-                preference.setSummary(getString(Utils.licenseNameFor((String) newValue)));
-                return true;
-            }
         });
 
         CheckBoxPreference themePreference = (CheckBoxPreference) findPreference("theme");
-        themePreference.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+        themePreference.setOnPreferenceChangeListener((preference, newValue) -> {
-            @Override
+            getActivity().recreate();
-            public boolean onPreferenceChange(Preference preference, Object newValue) {
+            return true;
-                getActivity().recreate();
-                return true;
-            }
         });
 
         final EditTextPreference uploadLimit = (EditTextPreference) findPreference("uploads");
@@ -51,36 +45,27 @@ public class SettingsFragment extends PreferenceFragment {
         int uploads = sharedPref.getInt(Prefs.UPLOADS_SHOWING, 100);
         uploadLimit.setText(uploads + "");
         uploadLimit.setSummary(uploads + "");
-        uploadLimit.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+        uploadLimit.setOnPreferenceChangeListener((preference, newValue) -> {
-
+            int value = Integer.parseInt(newValue.toString());
-            @Override
+            final SharedPreferences.Editor editor = sharedPref.edit();
-            public boolean onPreferenceChange(Preference preference, Object newValue) {
+            if (value > 500) {
-                int value = Integer.parseInt(newValue.toString());
+                new AlertDialog.Builder(getActivity())
-                final SharedPreferences.Editor editor = sharedPref.edit();
+                        .setTitle(R.string.maximum_limit)
-                if (value > 500) {
+                        .setMessage(R.string.maximum_limit_alert)
-                    new AlertDialog.Builder(getActivity())
+                        .setPositiveButton(android.R.string.yes, (dialog, which) -> {})
-                            .setTitle(R.string.maximum_limit)
+                        .setIcon(android.R.drawable.ic_dialog_alert)
-                            .setMessage(R.string.maximum_limit_alert)
+                        .show();
-                            .setPositiveButton(android.R.string.yes,
+                editor.putInt(Prefs.UPLOADS_SHOWING, 500);
-                                    new DialogInterface.OnClickListener() {
+                editor.putBoolean(Prefs.IS_CONTRIBUTION_COUNT_CHANGED,true);
-                                        public void onClick(DialogInterface dialog, int which) {
+                uploadLimit.setSummary(500 + "");
-                                        }
+                uploadLimit.setText(500 + "");
-                                    })
+            } else {
-                            .setIcon(android.R.drawable.ic_dialog_alert)
+                editor.putInt(Prefs.UPLOADS_SHOWING, Integer.parseInt(newValue.toString()));
-                            .show();
+                editor.putBoolean(Prefs.IS_CONTRIBUTION_COUNT_CHANGED,true);
-                    editor.putInt(Prefs.UPLOADS_SHOWING, 500);
+                uploadLimit.setSummary(newValue.toString());
-                    editor.putBoolean(Prefs.IS_CONTRIBUTION_COUNT_CHANGED,true);
-                    uploadLimit.setSummary(500 + "");
-                    uploadLimit.setText(500 + "");
-                } else {
-                    editor.putInt(Prefs.UPLOADS_SHOWING, Integer.parseInt(newValue.toString()));
-                    editor.putBoolean(Prefs.IS_CONTRIBUTION_COUNT_CHANGED,true);
-                    uploadLimit.setSummary(newValue.toString());
-                }
-                editor.apply();
-                return true;
             }
-
+            editor.apply();
+            return true;
         });
 
 

app/src/main/java/fr/free/nrw/commons/theme/NavigationBaseActivity.java

@@ -3,6 +3,7 @@ package fr.free.nrw.commons.theme;
 import android.content.ActivityNotFoundException;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.net.Uri;
 import android.support.annotation.NonNull;
 import android.support.design.widget.NavigationView;
 import android.support.v4.widget.DrawerLayout;
@@ -55,12 +56,7 @@ public class NavigationBaseActivity extends BaseActivity
     public void initBackButton() {
         int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
         toggle.setDrawerIndicatorEnabled(backStackEntryCount == 0);
-        toggle.setToolbarNavigationClickListener(new View.OnClickListener() {
+        toggle.setToolbarNavigationClickListener(v -> onBackPressed());
-            @Override
-            public void onClick(View v) {
-                onBackPressed();
-            }
-        });
     }
 
     public void initBack() {
@@ -114,29 +110,29 @@ public class NavigationBaseActivity extends BaseActivity
                     Toast.makeText(this, R.string.no_email_client, Toast.LENGTH_SHORT).show();
                 }
                 return true;
+            case R.id.action_developer_plans:
+                drawerLayout.closeDrawer(navigationView);
+                // Go to the page
+                Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri
+                        .parse(getResources()
+                                .getString(R.string.feedback_page_url)));
+                startActivity(browserIntent);
+                return true;
             case R.id.action_logout:
                 new AlertDialog.Builder(this)
                         .setMessage(R.string.logout_verification)
                         .setCancelable(false)
-                        .setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
+                        .setPositiveButton(R.string.yes, (dialog, which) -> {
-                            @Override
+                            ((CommonsApplication) getApplicationContext())
-                            public void onClick(DialogInterface dialog, int which) {
+                                    .clearApplicationData(NavigationBaseActivity.this);
-                                ((CommonsApplication) getApplicationContext())
+                            Intent nearbyIntent = new Intent(
-                                        .clearApplicationData(NavigationBaseActivity.this);
+                                    NavigationBaseActivity.this, LoginActivity.class);
-                                Intent nearbyIntent = new Intent(
+                            nearbyIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
-                                        NavigationBaseActivity.this, LoginActivity.class);
+                            nearbyIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-                                nearbyIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
+                            startActivity(nearbyIntent);
-                                nearbyIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+                            finish();
-                                startActivity(nearbyIntent);
-                                finish();
-                            }
-                        })
-                        .setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
-                            @Override
-                            public void onClick(DialogInterface dialog, int which) {
-                                dialog.cancel();
-                            }
                         })
+                        .setNegativeButton(R.string.no, (dialog, which) -> dialog.cancel())
                         .show();
                 return true;
             default:

app/src/main/java/fr/free/nrw/commons/upload/ExistingFileAsync.java

@@ -72,21 +72,13 @@ public class ExistingFileAsync extends AsyncTask<Void, Void, Boolean> {
             AlertDialog.Builder builder = new AlertDialog.Builder(context);
             builder.setMessage(R.string.file_exists)
                     .setTitle(R.string.warning);
-            builder.setPositiveButton(R.string.no, new DialogInterface.OnClickListener() {
+            builder.setPositiveButton(R.string.no, (dialog, id) -> {
-                @Override
+                //Go back to ContributionsActivity
-                public void onClick(DialogInterface dialog, int id) {
+                Intent intent = new Intent(context, ContributionsActivity.class);
-                    //Go back to ContributionsActivity
+                context.startActivity(intent);
-                    Intent intent = new Intent(context, ContributionsActivity.class);
+                callback.onResult(Result.DUPLICATE_CANCELLED);
-                    context.startActivity(intent);
-                    callback.onResult(Result.DUPLICATE_CANCELLED);
-                }
-            });
-            builder.setNegativeButton(R.string.yes, new DialogInterface.OnClickListener() {
-                @Override
-                public void onClick(DialogInterface dialog, int id) {
-                    callback.onResult(Result.DUPLICATE_PROCEED);
-                }
             });
+            builder.setNegativeButton(R.string.yes, (dialog, id) -> callback.onResult(Result.DUPLICATE_PROCEED));
 
             AlertDialog dialog = builder.create();
             dialog.show();

app/src/main/java/fr/free/nrw/commons/upload/MultipleShareActivity.java

@@ -11,6 +11,7 @@ import android.database.DataSetObserver;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.content.ContextCompat;
@@ -28,6 +29,7 @@ import fr.free.nrw.commons.Media;
 import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.auth.AuthenticatedActivity;
 import fr.free.nrw.commons.category.CategorizationFragment;
+import fr.free.nrw.commons.category.OnCategoriesSaveHandler;
 import fr.free.nrw.commons.contributions.Contribution;
 import fr.free.nrw.commons.media.MediaDetailPagerFragment;
 import fr.free.nrw.commons.modifications.CategoryModifier;
@@ -43,7 +45,7 @@ public  class       MultipleShareActivity
                     AdapterView.OnItemClickListener,
                     FragmentManager.OnBackStackChangedListener,
                     MultipleUploadListFragment.OnMultipleUploadInitiatedHandler,
-        CategorizationFragment.OnCategoriesSaveHandler {
+        OnCategoriesSaveHandler {
     private CommonsApplication app;
     private ArrayList<Contribution> photosList = null;
 
@@ -104,7 +106,7 @@ public  class       MultipleShareActivity
     }
 
     @Override
-    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
         if (requestCode == 1 && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
             multipleUploadBegins();
         }
@@ -125,19 +127,16 @@ public  class       MultipleShareActivity
             Contribution up = photosList.get(i);
             final int uploadCount = i + 1; // Goddamn Java
 
-            uploadController.startUpload(up, new UploadController.ContributionUploadProgress() {
+            uploadController.startUpload(up, contribution -> {
-                @Override
+                dialog.setProgress(uploadCount);
-                public void onUploadStarted(Contribution contribution) {
+                if (uploadCount == photosList.size()) {
-                    dialog.setProgress(uploadCount);
+                    dialog.dismiss();
-                    if(uploadCount == photosList.size()) {
+                    Toast startingToast = Toast.makeText(
-                        dialog.dismiss();
+                            CommonsApplication.getInstance(),
-                        Toast startingToast = Toast.makeText(
+                            R.string.uploading_started,
-                                CommonsApplication.getInstance(),
+                            Toast.LENGTH_LONG
-                                R.string.uploading_started,
+                    );
-                                Toast.LENGTH_LONG
+                    startingToast.show();
-                        );
-                        startingToast.show();
-                    }
                 }
             });
         }

app/src/main/java/fr/free/nrw/commons/upload/MwVolleyApi.java

@@ -57,7 +57,7 @@ public class MwVolleyApi {
         Timber.d("URL: %s", apiUrl);
 
         JsonRequest<QueryResponse> request = new QueryRequest(apiUrl,
-                new LogResponseListener<QueryResponse>(), new LogResponseErrorListener());
+                new LogResponseListener<>(), new LogResponseErrorListener());
         getQueue().add(request);
     }
 

app/src/main/java/fr/free/nrw/commons/upload/ShareActivity.java

@@ -9,6 +9,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
 import android.os.ParcelFileDescriptor;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.support.design.widget.Snackbar;
@@ -36,6 +37,7 @@ import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.Utils;
 import fr.free.nrw.commons.auth.AuthenticatedActivity;
 import fr.free.nrw.commons.category.CategorizationFragment;
+import fr.free.nrw.commons.category.OnCategoriesSaveHandler;
 import fr.free.nrw.commons.contributions.Contribution;
 import fr.free.nrw.commons.modifications.CategoryModifier;
 import fr.free.nrw.commons.modifications.ModificationsContentProvider;
@@ -44,6 +46,9 @@ import fr.free.nrw.commons.modifications.TemplateRemoveModifier;
 import fr.free.nrw.commons.mwapi.EventLog;
 import timber.log.Timber;
 
+import static fr.free.nrw.commons.upload.ExistingFileAsync.Result.DUPLICATE_PROCEED;
+import static fr.free.nrw.commons.upload.ExistingFileAsync.Result.NO_DUPLICATE;
+
 /**
  * Activity for the title/desc screen after image is selected. Also starts processing image
  * GPS coordinates or user location (if enabled in Settings) for category suggestions.
@@ -51,7 +56,7 @@ import timber.log.Timber;
 public  class       ShareActivity
         extends     AuthenticatedActivity
         implements  SingleUploadFragment.OnUploadActionInitiated,
-        CategorizationFragment.OnCategoriesSaveHandler {
+        OnCategoriesSaveHandler {
 
     private static final int REQUEST_PERM_ON_CREATE_STORAGE = 1;
     private static final int REQUEST_PERM_ON_CREATE_LOCATION = 2;
@@ -133,12 +138,9 @@ public  class       ShareActivity
             Timber.d("Cache the categories found");
         }
 
-        uploadController.startUpload(title, mediaUri, description, mimeType, source, decimalCoords, new UploadController.ContributionUploadProgress() {
+        uploadController.startUpload(title, mediaUri, description, mimeType, source, decimalCoords, c -> {
-            @Override
+            ShareActivity.this.contribution = c;
-            public void onUploadStarted(Contribution contribution) {
+            showPostUpload();
-                ShareActivity.this.contribution = contribution;
-                showPostUpload();
-            }
         });
     }
 
@@ -317,7 +319,7 @@ public  class       ShareActivity
 
     @Override
     public void onRequestPermissionsResult(int requestCode,
-                                           String[] permissions, int[] grantResults) {
+                                           @NonNull String[] permissions, @NonNull int[] grantResults) {
         switch (requestCode) {
             case REQUEST_PERM_ON_CREATE_STORAGE: {
                 if (grantResults.length >= 1
@@ -379,14 +381,10 @@ public  class       ShareActivity
                     Timber.d("File SHA1 is: %s", fileSHA1);
 
                     ExistingFileAsync fileAsyncTask =
-                            new ExistingFileAsync(fileSHA1, this, new ExistingFileAsync.Callback() {
+                            new ExistingFileAsync(fileSHA1, this, result -> {
-                                @Override
+                                Timber.d("%s duplicate check: %s", mediaUri.toString(), result);
-                                public void onResult(ExistingFileAsync.Result result) {
+                                duplicateCheckPassed = (result == DUPLICATE_PROCEED
-                                    Timber.d("%s duplicate check: %s", mediaUri.toString(), result);
+                                        || result == NO_DUPLICATE);
-                                    duplicateCheckPassed =
-                                            result == ExistingFileAsync.Result.DUPLICATE_PROCEED
-                                                    || result == ExistingFileAsync.Result.NO_DUPLICATE;
-                                }
                             });
                     fileAsyncTask.execute();
                 } catch (IOException e) {
@@ -401,17 +399,12 @@ public  class       ShareActivity
         }
     }
 
-    private Snackbar requestPermissionUsingSnackBar(
+    private Snackbar requestPermissionUsingSnackBar(String rationale,
-            String rationale, final String[] perms, final int code) {
+                                                    final String[] perms,
+                                                    final int code) {
         Snackbar snackbar = Snackbar.make(findViewById(android.R.id.content), rationale,
-                Snackbar.LENGTH_INDEFINITE)
+                Snackbar.LENGTH_INDEFINITE).setAction(R.string.ok,
-                .setAction(R.string.ok, new View.OnClickListener() {
+                view -> ActivityCompat.requestPermissions(ShareActivity.this, perms, code));
-                    @Override
-                    public void onClick(View view) {
-                        ActivityCompat.requestPermissions(ShareActivity.this,
-                                perms, code);
-                    }
-                });
         snackbar.show();
         return snackbar;
     }

app/src/main/java/fr/free/nrw/commons/utils/ExecutorUtils.java

@@ -7,14 +7,11 @@ import java.util.concurrent.Executor;
 
 public class ExecutorUtils {
 
-    private static final Executor uiExecutor = new Executor() {
+    private static final Executor uiExecutor = command -> {
-        @Override
+        if (Looper.myLooper() == Looper.getMainLooper()) {
-        public void execute(Runnable command) {
+            command.run();
-            if (Looper.myLooper() == Looper.getMainLooper()) {
+        } else {
-                command.run();
+            new Handler(Looper.getMainLooper()).post(command);
-            } else {
-                new Handler(Looper.getMainLooper()).post(command);
-            }
         }
     };
 

app/src/main/java/fr/free/nrw/commons/utils/FileUtils.java

@@ -42,8 +42,8 @@ public class FileUtils {
         if (file != null) {
             if (file.isDirectory()) {
                 String[] children = file.list();
-                for (int i = 0; i < children.length; i++) {
+                for (String child : children) {
-                    deletedAll = deleteFile(new File(file, children[i])) && deletedAll;
+                    deletedAll = deleteFile(new File(file, child)) && deletedAll;
                 }
             } else {
                 deletedAll = file.delete();