When a window is first shown only draw once while animating.

On some hardware allocating a new graphics buffer is quite
expensive, which blocks updates to the UI.  This can cause
glitches when performing window animations.

To reduce these glitches, the view hierarchy will now only
allow itself to be drawn once if its window is being shown
while the window manager is animating, not resuming draws
until it is told that the animation is done.

Change-Id: Ie15192f6fddbd0931b022a72c76ddd55ca266d84

Author: Dianne Hackborn

core/java/android/view/IWindow.aidl

@@ -70,11 +70,18 @@ oneway interface IWindow {
     /**
      * Drag/drop events
      */
-     void dispatchDragEvent(in DragEvent event);
+    void dispatchDragEvent(in DragEvent event);
 
     /**
      * System chrome visibility changes
      */
-     void dispatchSystemUiVisibilityChanged(int seq, int globalVisibility,
+    void dispatchSystemUiVisibilityChanged(int seq, int globalVisibility,
             int localValue, int localChanges);
+
+    /**
+     * If the window manager returned RELAYOUT_RES_ANIMATING
+     * from relayout(), this method will be called when the animation
+     * is done.
+     */
+    void doneAnimating();
 }

core/java/android/view/ViewRootImpl.java

@@ -229,6 +229,7 @@ public final class ViewRootImpl implements ViewParent,
     boolean mNewSurfaceNeeded;
     boolean mHasHadWindowFocus;
     boolean mLastWasImTarget;
+    boolean mWindowsAnimating;
     int mLastSystemUiVisibility;
 
     // Pool of queued input events.
@@ -1768,6 +1769,8 @@ private void performTraversals() {
             }
         }
 
+        boolean skipDraw = false;
+
         if (mFirst) {
             // handle first focus request
             if (DEBUG_INPUT_RESIZE) Log.v(TAG, "First: mView.hasFocus()="
@@ -1784,6 +1787,14 @@ private void performTraversals() {
                             + mRealFocusedView);
                 }
             }
+            if ((relayoutResult&WindowManagerImpl.RELAYOUT_RES_ANIMATING) != 0) {
+                // The first time we relayout the window, if the system is
+                // doing window animations, we want to hold of on any future
+                // draws until the animation is done.
+                mWindowsAnimating = true;
+            }
+        } else if (mWindowsAnimating) {
+            skipDraw = true;
         }
 
         mFirst = false;
@@ -1815,14 +1826,16 @@ private void performTraversals() {
                 viewVisibility != View.VISIBLE;
 
         if (!cancelDraw && !newSurface) {
-            if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
-                for (int i = 0; i < mPendingTransitions.size(); ++i) {
-                    mPendingTransitions.get(i).startChangingAnimations();
+            if (!skipDraw || mReportNextDraw) {
+                if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
+                    for (int i = 0; i < mPendingTransitions.size(); ++i) {
+                        mPendingTransitions.get(i).startChangingAnimations();
+                    }
+                    mPendingTransitions.clear();
                 }
-                mPendingTransitions.clear();
+    
+                performDraw();
             }
-
-            performDraw();
         } else {
             // End any pending transitions on this non-visible window
             if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
@@ -2680,6 +2693,7 @@ private static void forceLayout(View view) {
     private final static int MSG_DISPATCH_SCREEN_STATE = 20;
     private final static int MSG_INVALIDATE_DISPLAY_LIST = 21;
     private final static int MSG_CLEAR_ACCESSIBILITY_FOCUS_HOST = 22;
+    private final static int MSG_DISPATCH_DONE_ANIMATING = 23;
 
     final class ViewRootHandler extends Handler {
         @Override
@@ -2729,6 +2743,8 @@ public String getMessageName(Message message) {
                     return "MSG_INVALIDATE_DISPLAY_LIST";
                 case MSG_CLEAR_ACCESSIBILITY_FOCUS_HOST:
                     return "MSG_CLEAR_ACCESSIBILITY_FOCUS_HOST";
+                case MSG_DISPATCH_DONE_ANIMATING:
+                    return "MSG_DISPATCH_DONE_ANIMATING";
             }
             return super.getMessageName(message);
         }
@@ -2941,6 +2957,9 @@ public void handleMessage(Message msg) {
             case MSG_CLEAR_ACCESSIBILITY_FOCUS_HOST: {
                 setAccessibilityFocusedHost(null);
             } break;
+            case MSG_DISPATCH_DONE_ANIMATING: {
+                handleDispatchDoneAnimating();
+            } break;
             }
         }
     }
@@ -3756,6 +3775,15 @@ public void handleDispatchSystemUiVisibilityChanged(SystemUiVisibilityInfo args)
         mView.dispatchSystemUiVisibilityChanged(args.globalVisibility);
     }
 
+    public void handleDispatchDoneAnimating() {
+        if (mWindowsAnimating) {
+            mWindowsAnimating = false;
+            if (!mDirty.isEmpty() || mIsAnimating)  {
+                scheduleTraversals();
+            }
+        }
+    }
+
     public void getLastTouchPoint(Point outLocation) {
         outLocation.x = (int) mLastTouchPoint.x;
         outLocation.y = (int) mLastTouchPoint.y;
@@ -4476,6 +4504,10 @@ public void dispatchSystemUiVisibilityChanged(int seq, int globalVisibility,
         mHandler.sendMessage(mHandler.obtainMessage(MSG_DISPATCH_SYSTEM_UI_VISIBILITY, args));
     }
 
+    public void dispatchDoneAnimating() {
+        mHandler.sendEmptyMessage(MSG_DISPATCH_DONE_ANIMATING);
+    }
+
     public void dispatchCheckFocus() {
         if (!mHandler.hasMessages(MSG_CHECK_FOCUS)) {
             // This will result in a call to checkFocus() below.
@@ -4783,6 +4815,13 @@ public void dispatchSystemUiVisibilityChanged(int seq, int globalVisibility,
                         localValue, localChanges);
             }
         }
+
+        public void doneAnimating() {
+            final ViewRootImpl viewAncestor = mViewAncestor.get();
+            if (viewAncestor != null) {
+                viewAncestor.dispatchDoneAnimating();
+            }
+        }
     }
 
     /**

core/java/android/view/WindowManagerImpl.java

@@ -73,6 +73,11 @@ public class WindowManagerImpl implements WindowManager {
      * The window manager has changed the surface from the last call.
      */
     public static final int RELAYOUT_RES_SURFACE_CHANGED = 0x4;
+    /**
+     * The window manager is currently animating.  It will call
+     * IWindow.doneAnimating() when done.
+     */
+    public static final int RELAYOUT_RES_ANIMATING = 0x8;
 
     /**
      * Flag for relayout: the client will be later giving

core/java/com/android/internal/view/BaseIWindow.java

@@ -87,4 +87,7 @@ public void dispatchWallpaperCommand(String action, int x, int y,
             }
         }
     }
+
+    public void doneAnimating() {
+    }
 }

services/java/com/android/server/wm/WindowManagerService.java

@@ -423,6 +423,12 @@ public void onReceive(Context context, Intent intent) {
     ArrayList<Pair<WindowState, IRemoteCallback>> mWaitingForDrawn
             = new ArrayList<Pair<WindowState, IRemoteCallback>>();
 
+    /**
+     * Windows that have called relayout() while we were running animations,
+     * so we need to tell when the animation is done.
+     */
+    final ArrayList<WindowState> mRelayoutWhileAnimating = new ArrayList<WindowState>();
+
     /**
      * Used when rebuilding window list to keep track of windows that have
      * been removed.
@@ -2647,6 +2653,7 @@ public int relayoutWindow(Session session, IWindow client, int seq,
         boolean inTouchMode;
         boolean configChanged;
         boolean surfaceChanged = false;
+        boolean animating;
 
         // if they don't have this permission, mask out the status bar bits
         int systemUiVisibility = 0;
@@ -2946,7 +2953,11 @@ public int relayoutWindow(Session session, IWindow client, int seq,
                 TAG, "Relayout of " + win + ": focusMayChange=" + focusMayChange);
 
             inTouchMode = mInTouchMode;
-            
+            animating = mAnimator.mAnimating;
+            if (animating && !mRelayoutWhileAnimating.contains(win)) {
+                mRelayoutWhileAnimating.add(win);
+            }
+
             mInputMonitor.updateInputWindowsLw(true /*force*/);
         }
 
@@ -2958,7 +2969,8 @@ public int relayoutWindow(Session session, IWindow client, int seq,
 
         return (inTouchMode ? WindowManagerImpl.RELAYOUT_RES_IN_TOUCH_MODE : 0)
                 | (displayed ? WindowManagerImpl.RELAYOUT_RES_FIRST_TIME : 0)
-                | (surfaceChanged ? WindowManagerImpl.RELAYOUT_RES_SURFACE_CHANGED : 0);
+                | (surfaceChanged ? WindowManagerImpl.RELAYOUT_RES_SURFACE_CHANGED : 0)
+                | (animating ? WindowManagerImpl.RELAYOUT_RES_ANIMATING : 0);
     }
 
     public void performDeferredDestroyWindow(Session session, IWindow client) {
@@ -8579,6 +8591,16 @@ private final void performLayoutAndPlaceSurfacesLockedInner(
             mToBottomApps.clear();
         }
 
+        if (!mAnimator.mAnimating && mRelayoutWhileAnimating.size() > 0) {
+            for (int j=mRelayoutWhileAnimating.size()-1; j>=0; j--) {
+                try {
+                    mRelayoutWhileAnimating.get(j).mClient.doneAnimating();
+                } catch (RemoteException e) {
+                }
+            }
+            mRelayoutWhileAnimating.clear();
+        }
+
         if (wallpaperDestroyed) {
             mLayoutNeeded |= adjustWallpaperWindowsLocked() != 0;
         }

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgeWindow.java

@@ -90,6 +90,10 @@ public void dispatchSystemUiVisibilityChanged(int seq, int globalUi,
         // pass for now.
     }
 
+    @Override
+    public void doneAnimating() {
+    }
+
     @Override
     public IBinder asBinder() {
         // pass for now.