Fix #2200: Prevent app from closing while navigating to Home (#2204)

* Fix #2200 Prevent app from closing while navigating to Home
* Add workaround for reorder activity Android bug in some API levels

app/src/main/AndroidManifest.xml

@@ -6,6 +6,7 @@
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.READ_SYNC_SETTINGS" />
     <uses-permission android:name="android.permission.READ_SYNC_STATS" />
+    <uses-permission android:name="android.permission.REORDER_TASKS" />
     <uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

app/src/main/java/fr/free/nrw/commons/bookmarks/BookmarksActivity.java

@@ -54,7 +54,7 @@ public class BookmarksActivity extends NavigationBaseActivity
      */
     public static void startYourself(Context context) {
         Intent intent = new Intent(context, BookmarksActivity.class);
-        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP);
         context.startActivity(intent);
     }
 

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

@@ -140,7 +140,7 @@ public class CategoryDetailsActivity extends NavigationBaseActivity
      */
     public static void startYourself(Context context, String categoryName) {
         Intent intent = new Intent(context, CategoryDetailsActivity.class);
-        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP);
         intent.putExtra("categoryName", categoryName);
         context.startActivity(intent);
     }

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

@@ -148,7 +148,7 @@ public class CategoryImagesActivity
      */
     public static void startYourself(Context context, String title, String categoryName) {
         Intent intent = new Intent(context, CategoryImagesActivity.class);
-        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP);
         intent.putExtra("title", title);
         intent.putExtra("categoryName", categoryName);
         context.startActivity(intent);

app/src/main/java/fr/free/nrw/commons/notification/NotificationActivity.java

@@ -136,7 +136,7 @@ public class NotificationActivity extends NavigationBaseActivity {
 
     public static void startYourself(Context context) {
         Intent intent = new Intent(context, NotificationActivity.class);
-        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+        intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP);
         context.startActivity(intent);
     }
 

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

@@ -2,11 +2,13 @@ package fr.free.nrw.commons.theme;
 
 import android.accounts.Account;
 import android.accounts.AccountManager;
+import android.app.ActivityManager;
 import android.content.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.net.Uri;
+import android.os.Build;
 import android.support.annotation.NonNull;
 import android.support.design.widget.NavigationView;
 import android.support.v4.widget.DrawerLayout;
@@ -44,6 +46,7 @@ public abstract class NavigationBaseActivity extends BaseActivity
         implements NavigationView.OnNavigationItemSelectedListener {
 
     private static final String FEATURED_IMAGES_CATEGORY = "Category:Featured_pictures_on_Wikimedia_Commons";
+    private boolean isRestoredToTop;
 
     @BindView(R.id.toolbar)
     Toolbar toolbar;
@@ -172,11 +175,13 @@ public abstract class NavigationBaseActivity extends BaseActivity
                 return true;
             case R.id.action_about:
                 drawerLayout.closeDrawer(navigationView);
-                startActivityWithFlags(this, AboutActivity.class, Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+                startActivityWithFlags(this, AboutActivity.class, Intent.FLAG_ACTIVITY_REORDER_TO_FRONT,
+                        Intent.FLAG_ACTIVITY_SINGLE_TOP);
                 return true;
             case R.id.action_settings:
                 drawerLayout.closeDrawer(navigationView);
-                startActivityWithFlags(this, SettingsActivity.class, Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+                startActivityWithFlags(this, SettingsActivity.class, Intent.FLAG_ACTIVITY_REORDER_TO_FRONT,
+                        Intent.FLAG_ACTIVITY_SINGLE_TOP);
                 return true;
             case R.id.action_introduction:
                 drawerLayout.closeDrawer(navigationView);
@@ -249,6 +254,31 @@ public abstract class NavigationBaseActivity extends BaseActivity
         context.startActivity(intent);
     }
 
+    /* This is a workaround for a known Android bug which is present in some API levels.
+       https://issuetracker.google.com/issues/36986021
+     */
+    @Override
+    protected void onNewIntent(Intent intent) {
+        super.onNewIntent(intent);
+        if ((intent.getFlags() | Intent.FLAG_ACTIVITY_REORDER_TO_FRONT) > 0) {
+            isRestoredToTop  = true;
+        }
+    }
+
+    @Override
+    public void finish() {
+        super.finish();
+        if (Build.VERSION.SDK_INT == 19 || Build.VERSION.SDK_INT == 24 || Build.VERSION.SDK_INT == 25
+                && !isTaskRoot() && isRestoredToTop) {
+            // Issue with FLAG_ACTIVITY_REORDER_TO_FRONT,
+            // Reordered activity back press will go to home unexpectly,
+            // Workaround: move reordered activity current task to front when it's finished.
+            ActivityManager tasksManager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
+            tasksManager.moveTaskToFront(getTaskId(), ActivityManager.MOVE_TASK_NO_USER_ACTION);
+        }
+    }
+
+
     /**
      * Handles visibility of navigation base toolbar
      * @param show : Used to handle visibility of toolbar