2 files changed, 86 insertions, 1 deletions

diff --git a/core/java/android/app/ActivityView.java b/core/java/android/app/ActivityView.java
index ac6cba138eed..5d0143a505f3 100644
--- a/core/java/android/app/ActivityView.java
+++ b/core/java/android/app/ActivityView.java
@@ -17,6 +17,7 @@
 package android.app;
 
 import android.annotation.NonNull;
+import android.app.ActivityManager.StackInfo;
 import android.content.Context;
 import android.content.Intent;
 import android.hardware.display.DisplayManager;
@@ -38,6 +39,8 @@ import android.view.WindowManagerGlobal;
 
 import dalvik.system.CloseGuard;
 
+import java.util.List;
+
 /**
  * Activity container that allows launching activities into itself and does input forwarding.
  * <p>Creation of this view is only allowed to callers who have
@@ -58,10 +61,13 @@ public class ActivityView extends ViewGroup {
     private final SurfaceCallback mSurfaceCallback;
     private StateCallback mActivityViewCallback;
 
+    private IActivityManager mActivityManager;
     private IInputForwarder mInputForwarder;
     // Temp container to store view coordinates on screen.
     private final int[] mLocationOnScreen = new int[2];
 
+    private TaskStackListener mTaskStackListener;
+
     private final CloseGuard mGuard = CloseGuard.get();
     private boolean mOpened; // Protected by mGuard.
 
@@ -76,6 +82,7 @@ public class ActivityView extends ViewGroup {
     public ActivityView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
 
+        mActivityManager = ActivityManager.getService();
         mSurfaceView = new SurfaceView(context);
         mSurfaceCallback = new SurfaceCallback();
         mSurfaceView.getHolder().addCallback(mSurfaceCallback);
@@ -303,6 +310,12 @@ public class ActivityView extends ViewGroup {
 
         mInputForwarder = InputManager.getInstance().createInputForwarder(
                 mVirtualDisplay.getDisplay().getDisplayId());
+        mTaskStackListener = new TaskBackgroundChangeListener();
+        try {
+            mActivityManager.registerTaskStackListener(mTaskStackListener);
+        } catch (RemoteException e) {
+            Log.e(TAG, "Failed to register task stack listener", e);
+        }
     }
 
     private void performRelease() {
@@ -317,6 +330,15 @@ public class ActivityView extends ViewGroup {
         }
         cleanTapExcludeRegion();
 
+        if (mTaskStackListener != null) {
+            try {
+                mActivityManager.unregisterTaskStackListener(mTaskStackListener);
+            } catch (RemoteException e) {
+                Log.e(TAG, "Failed to unregister task stack listener", e);
+            }
+            mTaskStackListener = null;
+        }
+
         final boolean displayReleased;
         if (mVirtualDisplay != null) {
             mVirtualDisplay.release();
@@ -369,4 +391,42 @@ public class ActivityView extends ViewGroup {
             super.finalize();
         }
     }
+
+    /**
+     * A task change listener that detects background color change of the topmost stack on our
+     * virtual display and updates the background of the surface view. This background will be shown
+     * when surface view is resized, but the app hasn't drawn its content in new size yet.
+     */
+    private class TaskBackgroundChangeListener extends TaskStackListener {
+
+        @Override
+        public void onTaskDescriptionChanged(int taskId, ActivityManager.TaskDescription td)
+                throws RemoteException {
+            if (mVirtualDisplay == null) {
+                return;
+            }
+
+            // Find the topmost task on our virtual display - it will define the background
+            // color of the surface view during resizing.
+            final int displayId = mVirtualDisplay.getDisplay().getDisplayId();
+            final List<StackInfo> stackInfoList = mActivityManager.getAllStackInfos();
+
+            // Iterate through stacks from top to bottom.
+            final int stackCount = stackInfoList.size();
+            for (int i = 0; i < stackCount; i++) {
+                final StackInfo stackInfo = stackInfoList.get(i);
+                // Only look for stacks on our virtual display.
+                if (stackInfo.displayId != displayId) {
+                    continue;
+                }
+                // Found the topmost stack on target display. Now check if the topmost task's
+                // description changed.
+                if (taskId == stackInfo.taskIds[stackInfo.taskIds.length - 1]) {
+                    mSurfaceView.setResizeBackgroundColor(td.getBackgroundColor());
+                }
+                break;
+            }
+        }
+    }
+
 }
diff --git a/core/java/android/view/SurfaceView.java b/core/java/android/view/SurfaceView.java
index 578679b12b9a..4a9da4a6672f 100644
--- a/core/java/android/view/SurfaceView.java
+++ b/core/java/android/view/SurfaceView.java
@@ -25,6 +25,7 @@ import android.content.Context;
 import android.content.res.CompatibilityInfo.Translator;
 import android.content.res.Configuration;
 import android.graphics.Canvas;
+import android.graphics.Color;
 import android.graphics.PixelFormat;
 import android.graphics.PorterDuff;
 import android.graphics.Rect;
@@ -114,7 +115,7 @@ public class SurfaceView extends View implements ViewRootImpl.WindowStoppedCallb
     final Rect mScreenRect = new Rect();
     SurfaceSession mSurfaceSession;
 
-    SurfaceControl mSurfaceControl;
+    SurfaceControlWithBackground mSurfaceControl;
     // In the case of format changes we switch out the surface in-place
     // we need to preserve the old one until the new one has drawn.
     SurfaceControl mDeferredDestroySurfaceControl;
@@ -925,6 +926,17 @@ public class SurfaceView extends View implements ViewRootImpl.WindowStoppedCallb
         return mSubLayer >= 0;
     }
 
+    /**
+     * Set an opaque background color to use with this {@link SurfaceView} when it's being resized
+     * and size of the content hasn't updated yet. This color will fill the expanded area when the
+     * view becomes larger.
+     * @param bgColor An opaque color to fill the background. Alpha component will be ignored.
+     * @hide
+     */
+    public void setResizeBackgroundColor(int bgColor) {
+        mSurfaceControl.setBackgroundColor(bgColor);
+    }
+
     private final SurfaceHolder mSurfaceHolder = new SurfaceHolder() {
         private static final String LOG_TAG = "SurfaceHolder";
 
@@ -1219,6 +1231,19 @@ public class SurfaceView extends View implements ViewRootImpl.WindowStoppedCallb
             mBackgroundControl.deferTransactionUntil(barrier, frame);
         }
 
+        /** Set the color to fill the background with. */
+        private void setBackgroundColor(int bgColor) {
+            final float[] colorComponents = new float[] { Color.red(bgColor) / 255.f,
+                    Color.green(bgColor) / 255.f, Color.blue(bgColor) / 255.f };
+
+            SurfaceControl.openTransaction();
+            try {
+                mBackgroundControl.setColor(colorComponents);
+            } finally {
+                SurfaceControl.closeTransaction();
+            }
+        }
+
         void updateBackgroundVisibility() {
             if (mOpaque && mVisible) {
                 mBackgroundControl.show();