Merge "Modifty the documentation for MediaRouter2.showSystemOutputSwitcher"

core/api/current.txt

@@ -24427,7 +24427,7 @@ package android.media {
     method public void registerTransferCallback(@NonNull java.util.concurrent.Executor, @NonNull android.media.MediaRouter2.TransferCallback);
     method public void setOnGetControllerHintsListener(@Nullable android.media.MediaRouter2.OnGetControllerHintsListener);
     method public void setRouteListingPreference(@Nullable android.media.RouteListingPreference);
-    method public void showSystemOutputSwitcher();
+    method public boolean showSystemOutputSwitcher();
     method public void stop();
     method public void transferTo(@NonNull android.media.MediaRoute2Info);
     method public void unregisterControllerCallback(@NonNull android.media.MediaRouter2.ControllerCallback);

media/java/android/media/IMediaRouterService.aidl

@@ -94,5 +94,5 @@ interface IMediaRouterService {
     void setSessionVolumeWithManager(IMediaRouter2Manager manager, int requestId,
             String sessionId, int volume);
     void releaseSessionWithManager(IMediaRouter2Manager manager, int requestId, String sessionId);
-    void showMediaOutputSwitcher(String packageName);
+    boolean showMediaOutputSwitcher(String packageName);
 }

media/java/android/media/MediaRouter2.java

@@ -461,16 +461,30 @@ public final class MediaRouter2 {
     }
 
     /**
-     * Shows the system UI output switcher.
+     * Shows the system output switcher dialog.
+     *
+     * <p>Should only be called when the context of MediaRouter2 is in the foreground and visible on
+     * the screen.
+     *
+     * <p>The appearance and precise behaviour of the system output switcher dialog may vary across
+     * different devices, OS versions, and form factors, but the basic functionality stays the same.
+     *
+     * <p>See <a
+     * href="https://developer.android.com/guide/topics/media/media-routing#output-switcher">Output
+     * Switcher documentation</a> for more details.
+     *
+     * @return {@code true} if the output switcher dialog is being shown, or {@code false} if the
+     * call is ignored because the app is in the background.
      */
-    public void showSystemOutputSwitcher() {
+    public boolean showSystemOutputSwitcher() {
         synchronized (mLock) {
             try {
-                mMediaRouterService.showMediaOutputSwitcher(mPackageName);
+                return mMediaRouterService.showMediaOutputSwitcher(mPackageName);
             } catch (RemoteException ex) {
                 ex.rethrowFromSystemServer();
             }
         }
+        return false;
     }
 
     /**

services/core/java/com/android/server/media/MediaRouterService.java

@@ -16,6 +16,8 @@
 
 package com.android.server.media;
 
+import static android.app.ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
@@ -248,12 +250,17 @@ public final class MediaRouterService extends IMediaRouterService.Stub
 
     // Binder call
     @Override
-    public void showMediaOutputSwitcher(String packageName) {
+    public boolean showMediaOutputSwitcher(String packageName) {
         if (!validatePackageName(Binder.getCallingUid(), packageName)) {
             throw new SecurityException("packageName must match the calling identity");
         }
         final long token = Binder.clearCallingIdentity();
         try {
+            if (mContext.getSystemService(ActivityManager.class).getPackageImportance(packageName)
+                    > IMPORTANCE_FOREGROUND) {
+                Slog.w(TAG, "showMediaOutputSwitcher only works when called from foreground");
+                return false;
+            }
             synchronized (mLock) {
                 StatusBarManagerInternal statusBar =
                         LocalServices.getService(StatusBarManagerInternal.class);
@@ -262,6 +269,7 @@ public final class MediaRouterService extends IMediaRouterService.Stub
         } finally {
             Binder.restoreCallingIdentity(token);
         }
+        return true;
     }
 
     // Binder call