instead of unbinding items from the loader, unregistering listeners

in activity.onDestroy()

Bug: 28740269
Change-Id: I6bf2ad6aca43970fd10cfbcc113e609c227e07bf

src/com/android/launcher3/FolderInfo.java

@@ -109,10 +109,8 @@ public class FolderInfo extends ItemInfo {
         listeners.add(listener);
     }
 
-    void removeListener(FolderListener listener) {
-        if (listeners.contains(listener)) {
-            listeners.remove(listener);
-        }
+    public void removeListener(FolderListener listener) {
+        listeners.remove(listener);
     }
 
     public void itemsChanged(boolean animate) {
@@ -121,12 +119,6 @@ public class FolderInfo extends ItemInfo {
         }
     }
 
-    @Override
-    void unbind() {
-        super.unbind();
-        listeners.clear();
-    }
-
     public interface FolderListener {
         public void onAdd(ShortcutInfo item);
         public void onRemove(ShortcutInfo item);

src/com/android/launcher3/ItemInfo.java

@@ -183,15 +183,6 @@ public class ItemInfo {
         }
     }
 
-    /**
-     * It is very important that sub-classes implement this if they contain any references
-     * to the activity (anything in the view hierarchy etc.). If not, leaks can result since
-     * ItemInfo objects persist across rotation and can hence leak by holding stale references
-     * to the old view hierarchy / activity.
-     */
-    void unbind() {
-    }
-
     @Override
     public String toString() {
         return "Item(id=" + this.id + " type=" + this.itemType + " container=" + this.container

src/com/android/launcher3/Launcher.java

@@ -1967,6 +1967,7 @@ public class Launcher extends Activity
         mHandler.removeMessages(ADVANCE_MSG);
         mHandler.removeMessages(0);
         mWorkspace.removeCallbacks(mBuildLayersRunnable);
+        mWorkspace.removeFolderListeners();
 
         // Stop callbacks from LauncherModel
         // It's possible to receive onDestroy after a new Launcher activity has
@@ -2365,6 +2366,9 @@ public class Launcher extends Activity
             }
         } else if (itemInfo instanceof FolderInfo) {
             final FolderInfo folderInfo = (FolderInfo) itemInfo;
+            if (v instanceof FolderIcon) {
+                ((FolderIcon) v).removeListeners();
+            }
             mWorkspace.removeWorkspaceItem(v);
             if (deleteFromDb) {
                 LauncherModel.deleteFolderAndContentsFromDatabase(this, folderInfo);

src/com/android/launcher3/LauncherModel.java

@@ -65,6 +65,7 @@ import com.android.launcher3.util.FlagOp;
 import com.android.launcher3.util.LongArrayMap;
 import com.android.launcher3.util.ManagedProfileHeuristic;
 import com.android.launcher3.util.PackageManagerHelper;
+import com.android.launcher3.util.Preconditions;
 import com.android.launcher3.util.StringFilter;
 import com.android.launcher3.util.Thunk;
 import com.android.launcher3.util.ViewOnDrawExecutor;
@@ -578,38 +579,6 @@ public class LauncherModel extends BroadcastReceiver
         runOnWorkerThread(r);
     }
 
-    private void unbindItemInfosAndClearQueuedBindRunnables() {
-        if (sWorkerThread.getThreadId() == Process.myTid()) {
-            throw new RuntimeException("Expected unbindLauncherItemInfos() to be called from the " +
-                    "main thread");
-        }
-
-        // Remove any queued UI runnables
-        mHandler.cancelAll();
-        // Unbind all the workspace items
-        unbindWorkspaceItemsOnMainThread();
-    }
-
-    /** Unbinds all the sBgWorkspaceItems and sBgAppWidgets on the main thread */
-    void unbindWorkspaceItemsOnMainThread() {
-        // Ensure that we don't use the same workspace items data structure on the main thread
-        // by making a copy of workspace items first.
-        final ArrayList<ItemInfo> tmpItems = new ArrayList<ItemInfo>();
-        synchronized (sBgLock) {
-            tmpItems.addAll(sBgWorkspaceItems);
-            tmpItems.addAll(sBgAppWidgets);
-        }
-        Runnable r = new Runnable() {
-                @Override
-                public void run() {
-                   for (ItemInfo item : tmpItems) {
-                       item.unbind();
-                   }
-                }
-            };
-        runOnMainThread(r);
-    }
-
     /**
      * Adds an item to the DB if it was not created previously, or move it to a new
      * <container, screen, cellX, cellY>
@@ -1137,10 +1106,10 @@ public class LauncherModel extends BroadcastReceiver
      */
     public void initialize(Callbacks callbacks) {
         synchronized (mLock) {
-            // Disconnect any of the callbacks and drawables associated with ItemInfos on the
-            // workspace to prevent leaking Launcher activities on orientation change.
-            unbindItemInfosAndClearQueuedBindRunnables();
-            mCallbacks = new WeakReference<Callbacks>(callbacks);
+            Preconditions.assertUIThread();
+            // Remove any queued UI runnables
+            mHandler.cancelAll();
+            mCallbacks = new WeakReference<>(callbacks);
         }
     }
 
@@ -2482,10 +2451,6 @@ public class LauncherModel extends BroadcastReceiver
             final long currentScreenId = currentScreen < 0
                     ? INVALID_SCREEN_ID : orderedScreenIds.get(currentScreen);
 
-            // Load all the items that are on the current page first (and in the process, unbind
-            // all the existing workspace items before we call startBinding() below.
-            unbindWorkspaceItemsOnMainThread();
-
             // Separate the items that are on the current screen, and all the other remaining items
             ArrayList<ItemInfo> currentWorkspaceItems = new ArrayList<>();
             ArrayList<ItemInfo> otherWorkspaceItems = new ArrayList<>();

src/com/android/launcher3/Workspace.java

@@ -3669,6 +3669,21 @@ public class Workspace extends PagedView
         }
     }
 
+    /**
+     * Removes all folder listeners
+     */
+    public void removeFolderListeners() {
+        mapOverItems(false, new ItemOperator() {
+            @Override
+            public boolean evaluate(ItemInfo info, View view) {
+                if (view instanceof FolderIcon) {
+                    ((FolderIcon) view).removeListeners();
+                }
+                return false;
+            }
+        });
+    }
+
     @Override
     public void deferCompleteDropAfterUninstallActivity() {
         mDeferDropAfterUninstall = true;

src/com/android/launcher3/folder/FolderIcon.java

@@ -1000,6 +1000,11 @@ public class FolderIcon extends FrameLayout implements FolderListener {
         mLongPressHelper.cancelLongPress();
     }
 
+    public void removeListeners() {
+        mInfo.removeListener(this);
+        mInfo.removeListener(mFolder);
+    }
+
     public interface PreviewLayoutRule {
         public PreviewItemDrawingParams computePreviewItemDrawingParams(int index, int curNumItems,
             PreviewItemDrawingParams params);