Destroy activity/view references to avoid memory leak

Bug: 204891006
Change-Id: If60ac1716c30ebe68fb6e7457d71f542d3075422

quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java

@@ -55,6 +55,7 @@ import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ValueAnimator;
 import android.annotation.TargetApi;
+import android.app.Activity;
 import android.app.ActivityManager;
 import android.content.Context;
 import android.content.Intent;
@@ -96,6 +97,7 @@ import com.android.quickstep.GestureState.GestureEndTarget;
 import com.android.quickstep.RemoteTargetGluer.RemoteTargetHandle;
 import com.android.quickstep.util.ActiveGestureLog;
 import com.android.quickstep.util.ActivityInitListener;
+import com.android.launcher3.util.ActivityLifecycleCallbacksAdapter;
 import com.android.quickstep.util.AnimatorControllerWithResistance;
 import com.android.quickstep.util.InputConsumerProxy;
 import com.android.quickstep.util.InputProxyHandlerFactory;
@@ -153,6 +155,17 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
     protected MultiStateCallback mStateCallback;
     protected boolean mCanceled;
     private boolean mRecentsViewScrollLinked = false;
+    private final ActivityLifecycleCallbacksAdapter mLifecycleCallbacks =
+            new ActivityLifecycleCallbacksAdapter() {
+                @Override
+                public void onActivityDestroyed(Activity activity) {
+                    if (mActivity != activity) {
+                        return;
+                    }
+                    mRecentsView = null;
+                    mActivity = null;
+                }
+            };
 
     private static int getFlagForIndex(int index, String name) {
         if (DEBUG_STATES) {
@@ -416,6 +429,7 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
         setupRecentsViewUi();
         linkRecentsViewScroll();
 
+        mActivity.registerActivityLifecycleCallbacks(mLifecycleCallbacks);
         return true;
     }
 
@@ -1542,6 +1556,9 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
 
     private void reset() {
         mStateCallback.setStateOnUiThread(STATE_HANDLER_INVALIDATED);
+        if (mActivity != null) {
+            mActivity.unregisterActivityLifecycleCallbacks(mLifecycleCallbacks);
+        }
     }
 
     /**

src/com/android/launcher3/util/ActivityLifecycleCallbacksAdapter.java

@@ -0,0 +1,29 @@
+package com.android.launcher3.util;
+
+import android.app.Activity;
+import android.app.Application.ActivityLifecycleCallbacks;
+import android.os.Bundle;
+
+public interface ActivityLifecycleCallbacksAdapter extends ActivityLifecycleCallbacks {
+
+    default void onActivityCreated(Activity activity, Bundle bundle) {
+    }
+
+    default void onActivityDestroyed(Activity activity) {
+    }
+
+    default void onActivityPaused(Activity activity) {
+    }
+
+    default void onActivityResumed(Activity activity) {
+    }
+
+    default void onActivitySaveInstanceState(Activity activity, Bundle bundle) {
+    }
+
+    default void onActivityStarted(Activity activity) {
+    }
+
+    default void onActivityStopped(Activity activity) {
+    }
+}