All apps memory leak fix / unregister data observer

Bug: 197702957

Test: adb shell dumpsys meminfo com.google.android.apps.nexuslauncher, ahat

Change-Id: Ia5732cced959e4a199d9c2b59f1f3941a2e23552
diff --git a/src/com/android/launcher3/allapps/AllAppsContainerView.java b/src/com/android/launcher3/allapps/AllAppsContainerView.java
index d2c71b2..f420ec2 100644
--- a/src/com/android/launcher3/allapps/AllAppsContainerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsContainerView.java
@@ -499,8 +499,10 @@
 
     private void replaceRVContainer(boolean showTabs) {
         for (int i = 0; i < mAH.length; i++) {
-            if (mAH[i].recyclerView != null) {
-                mAH[i].recyclerView.setLayoutManager(null);
+            AllAppsRecyclerView rv = mAH[i].recyclerView;
+            if (rv != null) {
+                rv.setLayoutManager(null);
+                rv.setAdapter(null);
             }
         }
         View oldView = getRecyclerViewContainer();
diff --git a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
index 2c84a3d..bddbbd0 100644
--- a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
@@ -63,6 +63,13 @@
     private final SparseIntArray mCachedScrollPositions = new SparseIntArray();
     private final AllAppsFastScrollHelper mFastScrollHelper;
 
+
+    private final AdapterDataObserver mObserver = new RecyclerView.AdapterDataObserver() {
+        public void onChanged() {
+            mCachedScrollPositions.clear();
+        }
+    };
+
     // The empty-search result background
     private AllAppsBackgroundDrawable mEmptySearchBackground;
     private int mEmptySearchBackgroundTopOffset;
@@ -247,12 +254,13 @@
 
     @Override
     public void setAdapter(Adapter adapter) {
+        if (getAdapter() != null) {
+            getAdapter().unregisterAdapterDataObserver(mObserver);
+        }
         super.setAdapter(adapter);
-        adapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
-            public void onChanged() {
-                mCachedScrollPositions.clear();
-            }
-        });
+        if (adapter != null) {
+            adapter.registerAdapterDataObserver(mObserver);
+        }
     }
 
     @Override