Fix stale data in keyguard transport control display

Make sure that caches are cleared at the right times and views have
their data populated correctly. Also fix a caching issue in
RemoteController.

Bug 11218218

Change-Id: Ieb833b5dc440ccd1b82050f12eb7059a4e0a412f

media/java/android/media/RemoteController.java

@@ -812,6 +812,7 @@ public final class RemoteController
         final OnClientUpdateListener l;
         synchronized(mInfoLock) {
             l = mOnClientUpdateListener;
+            mMetadataEditor = null;
         }
         if (l != null) {
             l.onClientChange(clearing);

packages/Keyguard/src/com/android/keyguard/KeyguardTransportControlView.java

@@ -101,9 +101,7 @@ public class KeyguardTransportControlView extends FrameLayout {
             new RemoteController.OnClientUpdateListener() {
         @Override
         public void onClientChange(boolean clearing) {
-            if (clearing) {
-                clearMetadata();
-            }
+            clearMetadata();
         }
 
         @Override
@@ -302,6 +300,7 @@ public class KeyguardTransportControlView extends FrameLayout {
             mPopulateMetadataWhenAttached = null;
         }
         if (DEBUG) Log.v(TAG, "Registering TCV " + this);
+        mMetadata.clear();
         mAudioManager.registerRemoteController(mRemoteController);
         KeyguardUpdateMonitor.getInstance(mContext).registerCallback(mUpdateMonitor);
     }
@@ -321,6 +320,7 @@ public class KeyguardTransportControlView extends FrameLayout {
         if (DEBUG) Log.v(TAG, "Unregistering TCV " + this);
         mAudioManager.unregisterRemoteController(mRemoteController);
         KeyguardUpdateMonitor.getInstance(mContext).removeCallback(mUpdateMonitor);
+        mMetadata.clear();
         mUserSeeking = false;
     }
 
@@ -394,10 +394,10 @@ public class KeyguardTransportControlView extends FrameLayout {
             Log.e(TAG, "Couldn't get remote control client package icon", e);
         }
         setBadgeIcon(badgeIcon);
-        if (!TextUtils.isEmpty(mMetadata.trackTitle)) {
-            mTrackTitle.setText(mMetadata.trackTitle);
-        }
-        StringBuilder sb = new StringBuilder();
+        mTrackTitle.setText(!TextUtils.isEmpty(mMetadata.trackTitle)
+                ? mMetadata.trackTitle : null);
+
+        final StringBuilder sb = new StringBuilder();
         if (!TextUtils.isEmpty(mMetadata.artist)) {
             if (sb.length() != 0) {
                 sb.append(" - ");
@@ -410,7 +410,10 @@ public class KeyguardTransportControlView extends FrameLayout {
             }
             sb.append(mMetadata.albumTitle);
         }
-        mTrackArtistAlbum.setText(sb.toString());
+
+        final String trackArtistAlbum = sb.toString();
+        mTrackArtistAlbum.setText(!TextUtils.isEmpty(trackArtistAlbum) ?
+                trackArtistAlbum : null);
 
         if (mMetadata.duration >= 0) {
             setSeekBarsEnabled(true);