Crash fix for rotate in media detail view

We were crashing when rotating in the detail view, because the detail
view fragment had assumed that its parent activity had already loaded
up its cursor and such before it got created -- an assumption which
fails dramatically when rotating, or switching away and back after
we got paged out of memory.

Check whether we got an object, and if not ask the parent to ping us
when it's done loading.

Also tweaked one of the older delay hacks to avoid a second crash
related to the pager's adapter.

Change-Id: Ib91c0fef0d8ffd0e6b8e0e4874f3ee9be3e9cf34

commons/src/main/java/org/wikimedia/commons/contributions/ContributionsActivity.java

@@ -1,5 +1,6 @@
 package org.wikimedia.commons.contributions;
 
+import android.database.DataSetObserver;
 import android.os.IBinder;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.LoaderManager;
@@ -12,6 +13,7 @@ import android.support.v4.widget.CursorAdapter;
 import android.util.Log;
 import android.view.View;
 import android.widget.AdapterView;
+import android.widget.Adapter;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuItem;
 
@@ -36,6 +38,7 @@ public  class       ContributionsActivity
     private Cursor allContributions;
     private ContributionsListFragment contributionsList;
     private MediaDetailPagerFragment mediaDetails;
+    private ArrayList<DataSetObserver> observersWaitingForLoad = new ArrayList<DataSetObserver>();
 
     private Campaign campaign;
 
@@ -226,6 +229,7 @@ public  class       ContributionsActivity
                 ((MediaListAdapter)contributionsList.getAdapter()).updateMediaList((ArrayList<Media>) result);
             }
         }
+        notifyAndClearDataSetObservers();
     }
 
     public void onLoaderReset(Loader cursorLoader) {
@@ -237,7 +241,10 @@ public  class       ContributionsActivity
     }
 
     public Media getMediaAtPosition(int i) {
-        if(campaign == null) {
+        if (contributionsList.getAdapter() == null) {
+            // not yet ready to return data
+            return null;
+        } else if(campaign == null) {
             return Contribution.fromCursor((Cursor) contributionsList.getAdapter().getItem(i));
         } else {
             return (Media) contributionsList.getAdapter().getItem(i);
@@ -255,6 +262,31 @@ public  class       ContributionsActivity
         // Do nothing for now
     }
 
+    private void notifyAndClearDataSetObservers() {
+        for (DataSetObserver observer : observersWaitingForLoad) {
+            observer.onChanged();
+        }
+        observersWaitingForLoad.clear();
+    }
+
+    public void registerDataSetObserver(DataSetObserver observer) {
+        Adapter adapter = contributionsList.getAdapter();
+        if (adapter == null) {
+            observersWaitingForLoad.add(observer);
+        } else {
+            adapter.registerDataSetObserver(observer);
+        }
+    }
+
+    public void unregisterDataSetObserver(DataSetObserver observer) {
+        Adapter adapter = contributionsList.getAdapter();
+        if (adapter == null) {
+            observersWaitingForLoad.remove(observer);
+        } else {
+            adapter.registerDataSetObserver(observer);
+        }
+    }
+
     public void onBackStackChanged() {
         if(mediaDetails != null && mediaDetails.isVisible()) {
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);

commons/src/main/java/org/wikimedia/commons/media/MediaDetailFragment.java

@@ -1,6 +1,7 @@
 package org.wikimedia.commons.media;
 
 import android.content.Intent;
+import android.database.DataSetObserver;
 import android.graphics.*;
 import android.os.*;
 import android.text.*;
@@ -62,6 +63,7 @@ public class MediaDetailFragment extends SherlockFragment {
     private boolean categoriesPresent = false;
     private ViewTreeObserver.OnGlobalLayoutListener layoutListener; // for layout stuff, only used once!
     private ViewTreeObserver.OnScrollChangedListener scrollListener;
+    DataSetObserver dataObserver;
     private AsyncTask<Void,Void,Boolean> detailFetchTask;
     private LicenseList licenseList;
 
@@ -93,7 +95,6 @@ public class MediaDetailFragment extends SherlockFragment {
             index = getArguments().getInt("index");
             initialListTop = 0;
         }
-        final Media media = detailProvider.getMediaAtPosition(index);
         categoryNames = new ArrayList<String>();
         categoryNames.add(getString(R.string.detail_panel_cats_loading));
 
@@ -113,18 +114,60 @@ public class MediaDetailFragment extends SherlockFragment {
 
         licenseList = new LicenseList(getActivity());
 
-        // Enable or disable editing on the title
+        Media media = detailProvider.getMediaAtPosition(index);
-        /*
+        if (media == null) {
-        title.setClickable(editable);
+            // Ask the detail provider to ping us when we're ready
-        title.setFocusable(editable);
+            Log.d("Commons", "MediaDetailFragment not yet ready to display details; registering observer");
-        title.setCursorVisible(editable);
+            dataObserver = new DataSetObserver() {
-        title.setFocusableInTouchMode(editable);
+                public void onChanged() {
-        if(!editable) {
+                    Log.d("Commons", "MediaDetailFragment ready to display delayed details!");
-            title.setBackgroundDrawable(null);
+                    detailProvider.unregisterDataSetObserver(dataObserver);
+                    dataObserver = null;
+                    displayMediaDetails(detailProvider.getMediaAtPosition(index));
+                }
+            };
+            detailProvider.registerDataSetObserver(dataObserver);
+        } else {
+            Log.d("Commons", "MediaDetailFragment ready to display details");
+            displayMediaDetails(media);
         }
-        */
 
+        // Progressively darken the image in the background when we scroll detail pane up
+        scrollListener = new ViewTreeObserver.OnScrollChangedListener() {
+            public void onScrollChanged() {
+                updateTheDarkness();
+            }
+        };
+        view.getViewTreeObserver().addOnScrollChangedListener(scrollListener);
 
+        // Layout layoutListener to size the spacer item relative to the available space.
+        // There may be a .... better way to do this.
+        layoutListener = new ViewTreeObserver.OnGlobalLayoutListener() {
+            private int currentHeight = -1;
+
+            public void onGlobalLayout() {
+                int viewHeight = view.getHeight();
+                //int textHeight = title.getLineHeight();
+                int paddingDp = 112;
+                float paddingPx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, paddingDp, getResources().getDisplayMetrics());
+                int newHeight = viewHeight - Math.round(paddingPx);
+
+                if (newHeight != currentHeight) {
+                    currentHeight = newHeight;
+                    ViewGroup.LayoutParams params = spacer.getLayoutParams();
+                    params.height = newHeight;
+                    spacer.setLayoutParams(params);
+
+                    scrollView.scrollTo(0, initialListTop);
+                }
+
+            }
+        };
+        view.getViewTreeObserver().addOnGlobalLayoutListener(layoutListener);
+        return view;
+    }
+
+    private void displayMediaDetails(final Media media) {
         String actualUrl = (media.getLocalUri() != null && TextUtils.isEmpty(media.getLocalUri().toString())) ? media.getLocalUri().toString() : media.getThumbnailUrl(640);
         if(actualUrl.startsWith("http")) {
             ImageLoader loader = ((CommonsApplication)getActivity().getApplicationContext()).getImageLoader();
@@ -212,58 +255,6 @@ public class MediaDetailFragment extends SherlockFragment {
         title.setText(media.getDisplayTitle());
         desc.setText(""); // fill in from network...
         license.setText(""); // fill in from network...
-
-        /*
-        title.addTextChangedListener(new TextWatcher() {
-            public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
-
-            }
-
-            public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
-                detailProvider.getMediaAtPosition(index).setFilename(title.getText().toString());
-                detailProvider.getMediaAtPosition(index).setTag("isDirty", true);
-                detailProvider.notifyDatasetChanged();
-            }
-
-            public void afterTextChanged(Editable editable) {
-
-            }
-        });
-        */
-
-        // Progressively darken the image in the background when we scroll detail pane up
-        scrollListener = new ViewTreeObserver.OnScrollChangedListener() {
-            public void onScrollChanged() {
-                updateTheDarkness();
-            }
-        };
-        view.getViewTreeObserver().addOnScrollChangedListener(scrollListener);
-
-        // Layout layoutListener to size the spacer item relative to the available space.
-        // There may be a .... better way to do this.
-        layoutListener = new ViewTreeObserver.OnGlobalLayoutListener() {
-            private int currentHeight = -1;
-
-            public void onGlobalLayout() {
-                int viewHeight = view.getHeight();
-                //int textHeight = title.getLineHeight();
-                int paddingDp = 112;
-                float paddingPx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, paddingDp, getResources().getDisplayMetrics());
-                int newHeight = viewHeight - Math.round(paddingPx);
-
-                if (newHeight != currentHeight) {
-                    currentHeight = newHeight;
-                    ViewGroup.LayoutParams params = spacer.getLayoutParams();
-                    params.height = newHeight;
-                    spacer.setLayoutParams(params);
-
-                    scrollView.scrollTo(0, initialListTop);
-                }
-
-            }
-        };
-        view.getViewTreeObserver().addOnGlobalLayoutListener(layoutListener);
-        return view;
     }
 
     @Override

commons/src/main/java/org/wikimedia/commons/media/MediaDetailPagerFragment.java

@@ -3,6 +3,7 @@ package org.wikimedia.commons.media;
 import android.app.DownloadManager;
 import android.content.*;
 import android.database.Cursor;
+import android.database.DataSetObserver;
 import android.net.*;
 import android.os.*;
 import android.support.v4.app.Fragment;
@@ -41,6 +42,8 @@ public class MediaDetailPagerFragment extends SherlockFragment implements ViewPa
         public Media getMediaAtPosition(int i);
         public int getTotalMediaCount();
         public void notifyDatasetChanged();
+        public void registerDataSetObserver(DataSetObserver observer);
+        public void unregisterDataSetObserver(DataSetObserver observer);
     }
     private class MediaDetailAdapter extends FragmentStatePagerAdapter {
 
@@ -80,17 +83,19 @@ public class MediaDetailPagerFragment extends SherlockFragment implements ViewPa
         View view = inflater.inflate(R.layout.fragment_media_detail_pager, container, false);
         pager = (ViewPager) view.findViewById(R.id.mediaDetailsPager);
         pager.setOnPageChangeListener(this);
-        pager.setAdapter(new MediaDetailAdapter(getChildFragmentManager()));
         if(savedInstanceState != null) {
             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() {
                 public void run() {
+                    pager.setAdapter(new MediaDetailAdapter(getChildFragmentManager()));
                     pager.setCurrentItem(pageNumber, false);
                     getSherlockActivity().supportInvalidateOptionsMenu();
                 }
             }, 100);
+        } else {
+            pager.setAdapter(new MediaDetailAdapter(getChildFragmentManager()));
         }
         return view;
     }

commons/src/main/java/org/wikimedia/commons/upload/MultipleShareActivity.java

@@ -5,6 +5,7 @@ import java.util.concurrent.*;
 
 import android.app.*;
 import android.content.*;
+import android.database.DataSetObserver;
 import android.net.*;
 import android.os.*;
 import android.support.v4.app.FragmentManager;
@@ -61,6 +62,13 @@ public  class       MultipleShareActivity
         }
     }
 
+    public void registerDataSetObserver(DataSetObserver observer) {
+        // fixme implement me if needed
+    }
+
+    public void unregisterDataSetObserver(DataSetObserver observer) {
+        // fixme implement me if needed
+    }
 
     public void onItemClick(AdapterView<?> adapterView, View view, int index, long item) {
         showDetail(index);