MediaRouter group volume reporting

RouteGroups always report back the loudest volume of their component
routes. Maintain this through volume update requests (such as those
reported by volume hard keys) such that each route updates
individually, but the group slider always indicates the loudest value.

Change-Id: I5de4b9048bf55682b6271e9485fe50496a1c97c2

Author: adamp

media/java/android/media/MediaRouter.java

@@ -1033,6 +1033,9 @@ public void setVolume(int volume) {
                 mVolume = volume;
                 setPlaybackInfoOnRcc(RemoteControlClient.PLAYBACKINFO_VOLUME, volume);
                 dispatchRouteVolumeChanged(this);
+                if (mGroup != null) {
+                    mGroup.memberVolumeChanged(this);
+                }
             }
         }
 
@@ -1148,6 +1151,7 @@ public void addRoute(RouteInfo route) {
             mRoutes.add(route);
             route.mGroup = this;
             mUpdateName = true;
+            updateVolume();
             dispatchRouteGrouped(route, this, at);
             routeUpdated();
         }
@@ -1171,6 +1175,7 @@ public void addRoute(RouteInfo route, int insertAt) {
             mRoutes.add(insertAt, route);
             route.mGroup = this;
             mUpdateName = true;
+            updateVolume();
             dispatchRouteGrouped(route, this, insertAt);
             routeUpdated();
         }
@@ -1188,6 +1193,7 @@ public void removeRoute(RouteInfo route) {
             mRoutes.remove(route);
             route.mGroup = null;
             mUpdateName = true;
+            updateVolume();
             dispatchRouteUngrouped(route, this);
             routeUpdated();
         }
@@ -1201,6 +1207,7 @@ public void removeRoute(int index) {
             RouteInfo route = mRoutes.remove(index);
             route.mGroup = null;
             mUpdateName = true;
+            updateVolume();
             dispatchRouteUngrouped(route, this);
             routeUpdated();
         }
@@ -1270,11 +1277,15 @@ public void requestUpdateVolume(int direction) {
             }
 
             final int routeCount = getRouteCount();
+            int volume = 0;
             for (int i = 0; i < routeCount; i++) {
                 final RouteInfo route = getRouteAt(i);
                 route.requestUpdateVolume(direction);
+                final int routeVol = route.getVolume();
+                if (routeVol > volume) {
+                    volume = routeVol;
+                }
             }
-            final int volume = Math.max(0, Math.min(mVolume + direction, maxVol));
             if (volume != mVolume) {
                 mVolume = volume;
                 dispatchRouteVolumeChanged(this);
@@ -1290,6 +1301,26 @@ void memberStatusChanged(RouteInfo info, CharSequence status) {
             setStatusInt(status);
         }
 
+        void memberVolumeChanged(RouteInfo info) {
+            updateVolume();
+        }
+
+        void updateVolume() {
+            // A group always represents the highest component volume value.
+            final int routeCount = getRouteCount();
+            int volume = 0;
+            for (int i = 0; i < routeCount; i++) {
+                final int routeVol = getRouteAt(i).getVolume();
+                if (routeVol > volume) {
+                    volume = routeVol;
+                }
+            }
+            if (volume != mVolume) {
+                mVolume = volume;
+                dispatchRouteVolumeChanged(this);
+            }
+        }
+
         @Override
         void routeUpdated() {
             int types = 0;