Preserve window during resize triggered relaunches.

This changes application code behavior when the activity relaunches due
to configuration change. It only applies to scenarios, where the
configuration change was triggered by a user generated resize of an
activity (i.e. user drags a corner of an activity and thus changes its
size).

Preserving a window means that we will keep the decor view and non
client decor view around, but remove all children views when the
activity gets destroyed. When the activity gets created again, it will
attach its new content to the preserved view hierarchy. Mind, we
actually recreate application side Window object, since some of its
features might changed, but we retain its elevation (to not trigger
relayout with new layout params).

Preserving the window also means that we don't call the window manager
service to remove and later add the window. Instead, we continue using a
single window state throughout the resize operation.

Change-Id: Ie3d2878ed09c99ff343044bfe7a29a0ba07a265e

1 files changed, 19 insertions, 16 deletions

diff --git a/core/java/android/app/ApplicationThreadNative.java b/core/java/android/app/ApplicationThreadNative.java
index f164a0a76d8f..bead625a0bc1 100644
--- a/core/java/android/app/ApplicationThreadNative.java
+++ b/core/java/android/app/ApplicationThreadNative.java
@@ -63,14 +63,14 @@ public abstract class ApplicationThreadNative extends Binder
         if (in != null) {
             return in;
         }
-        
+
         return new ApplicationThreadProxy(obj);
     }
-    
+
     public ApplicationThreadNative() {
         attachInterface(this, descriptor);
     }
-    
+
     @Override
     public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
             throws RemoteException {
@@ -96,7 +96,7 @@ public abstract class ApplicationThreadNative extends Binder
             scheduleStopActivity(b, show, configChanges);
             return true;
         }
-        
+
         case SCHEDULE_WINDOW_VISIBILITY_TRANSACTION:
         {
             data.enforceInterface(IApplicationThread.descriptor);
@@ -125,7 +125,7 @@ public abstract class ApplicationThreadNative extends Binder
             scheduleResumeActivity(b, procState, isForward, resumeArgs);
             return true;
         }
-        
+
         case SCHEDULE_SEND_RESULT_TRANSACTION:
         {
             data.enforceInterface(IApplicationThread.descriptor);
@@ -179,7 +179,9 @@ public abstract class ApplicationThreadNative extends Binder
             if (data.readInt() != 0) {
                 overrideConfig = Configuration.CREATOR.createFromParcel(data);
             }
-            scheduleRelaunchActivity(b, ri, pi, configChanges, notResumed, config, overrideConfig);
+            boolean preserveWindows = data.readInt() == 1;
+            scheduleRelaunchActivity(b, ri, pi, configChanges, notResumed, config, overrideConfig,
+                    preserveWindows);
             return true;
         }
 
@@ -201,7 +203,7 @@ public abstract class ApplicationThreadNative extends Binder
             scheduleDestroyActivity(b, finishing, configChanges);
             return true;
         }
-        
+
         case SCHEDULE_RECEIVER_TRANSACTION:
         {
             data.enforceInterface(IApplicationThread.descriptor);
@@ -371,7 +373,7 @@ public abstract class ApplicationThreadNative extends Binder
             }
             return true;
         }
-        
+
         case DUMP_PROVIDER_TRANSACTION: {
             data.enforceInterface(IApplicationThread.descriptor);
             ParcelFileDescriptor fd = data.readFileDescriptor();
@@ -731,15 +733,15 @@ public abstract class ApplicationThreadNative extends Binder
 
 class ApplicationThreadProxy implements IApplicationThread {
     private final IBinder mRemote;
-    
+
     public ApplicationThreadProxy(IBinder remote) {
         mRemote = remote;
     }
-    
+
     public final IBinder asBinder() {
         return mRemote;
     }
-    
+
     public final void schedulePauseActivity(IBinder token, boolean finished,
             boolean userLeaving, int configChanges, boolean dontReport) throws RemoteException {
         Parcel data = Parcel.obtain();
@@ -856,7 +858,7 @@ class ApplicationThreadProxy implements IApplicationThread {
     public final void scheduleRelaunchActivity(IBinder token,
             List<ResultInfo> pendingResults, List<ReferrerIntent> pendingNewIntents,
             int configChanges, boolean notResumed, Configuration config,
-            Configuration overrideConfig) throws RemoteException {
+            Configuration overrideConfig, boolean preserveWindow) throws RemoteException {
         Parcel data = Parcel.obtain();
         data.writeInterfaceToken(IApplicationThread.descriptor);
         data.writeStrongBinder(token);
@@ -871,6 +873,7 @@ class ApplicationThreadProxy implements IApplicationThread {
         } else {
             data.writeInt(0);
         }
+        data.writeInt(preserveWindow ? 1 : 0);
         mRemote.transact(SCHEDULE_RELAUNCH_ACTIVITY_TRANSACTION, data, null,
                 IBinder.FLAG_ONEWAY);
         data.recycle();
@@ -898,7 +901,7 @@ class ApplicationThreadProxy implements IApplicationThread {
                 IBinder.FLAG_ONEWAY);
         data.recycle();
     }
-    
+
     public final void scheduleReceiver(Intent intent, ActivityInfo info,
             CompatibilityInfo compatInfo, int resultCode, String resultData,
             Bundle map, boolean sync, int sendingUser, int processState) throws RemoteException {
@@ -940,7 +943,7 @@ class ApplicationThreadProxy implements IApplicationThread {
                 IBinder.FLAG_ONEWAY);
         data.recycle();
     }
-    
+
     public final void scheduleCreateService(IBinder token, ServiceInfo info,
             CompatibilityInfo compatInfo, int processState) throws RemoteException {
         Parcel data = Parcel.obtain();
@@ -1055,7 +1058,7 @@ class ApplicationThreadProxy implements IApplicationThread {
                 IBinder.FLAG_ONEWAY);
         data.recycle();
     }
-    
+
     public final void scheduleExit() throws RemoteException {
         Parcel data = Parcel.obtain();
         data.writeInterfaceToken(IApplicationThread.descriptor);
@@ -1128,7 +1131,7 @@ class ApplicationThreadProxy implements IApplicationThread {
         mRemote.transact(DUMP_SERVICE_TRANSACTION, data, null, IBinder.FLAG_ONEWAY);
         data.recycle();
     }
-    
+
     public void dumpProvider(FileDescriptor fd, IBinder token, String[] args)
             throws RemoteException {
         Parcel data = Parcel.obtain();