Add support for RatingCompat

Replaces the "thumbs up"/"thumbs down" actions with a fully fledged
rating control that supports the various kinds of RatingCompats, e.g.
Stars, Thumbs, 3/4/5-stars, and percentages.

Also adds support for displaying the current rating in the same control
by selectively tinting the icons.

Author: soumya92

mediacontroller/src/main/java/com/example/android/mediacontroller/Action.java

@@ -162,17 +162,6 @@ public static List createActions(@NonNull final Context context) {
                 controller.getTransportControls().skipToPrevious());
         actions.add(action);
 
-        action = new Action(R.id.action_thumbs_up, context.getString(R.string.action_thumbs_up));
-        action.setMediaControllerAction((controller, id, extras) ->
-                controller.getTransportControls().setRating(RatingCompat.newThumbRating(true)));
-        actions.add(action);
-
-        action = new Action(R.id.action_thumbs_down,
-                context.getString(R.string.action_thumbs_down));
-        action.setMediaControllerAction((controller, id, extras) ->
-                controller.getTransportControls().setRating(RatingCompat.newThumbRating(false)));
-        actions.add(action);
-
         action = new Action(R.id.action_skip_30s_backward,
                 context.getString(R.string.action_skip_30s_backward));
         action.setMediaControllerAction((controller, id, extras) -> {

mediacontroller/src/main/java/com/example/android/mediacontroller/MediaAppControllerActivity.java

@@ -38,6 +38,7 @@
 import android.support.v4.graphics.drawable.DrawableCompat;
 import android.support.v4.media.MediaBrowserServiceCompat;
 import android.support.v4.media.MediaMetadataCompat;
+import android.support.v4.media.RatingCompat;
 import android.support.v4.media.session.MediaControllerCompat;
 import android.support.v4.media.session.MediaSessionCompat;
 import android.support.v4.media.session.PlaybackStateCompat;
@@ -122,6 +123,7 @@ public class MediaAppControllerActivity extends AppCompatActivity {
     private MediaAppDetails mMediaAppDetails;
     private MediaControllerCompat mController;
     private AudioFocusHelper mAudioFocusHelper;
+    private RatingUiHelper mRatingUiHelper;
     private CustomControlsAdapter mCustomControlsAdapter = new CustomControlsAdapter();
 
     private Spinner mInputTypeView;
@@ -136,6 +138,8 @@ public class MediaAppControllerActivity extends AppCompatActivity {
     private ModeHelper mShuffleToggle;
     private ModeHelper mRepeatToggle;
 
+    private ViewGroup mRatingViewGroup;
+
     private final SparseArray<ImageButton> mActionButtonMap = new SparseArray<>();
 
     /**
@@ -171,6 +175,8 @@ protected void onCreate(Bundle savedInstanceState) {
         mShuffleToggle = new ShuffleModeHelper();
         mRepeatToggle = new RepeatModeHelper();
 
+        mRatingViewGroup = findViewById(R.id.rating);
+
         if (savedInstanceState != null) {
             mMediaAppDetails = savedInstanceState.getParcelable(STATE_APP_DETAILS_KEY);
             mUriInput.setText(savedInstanceState.getString(STATE_URI_KEY));
@@ -323,6 +329,7 @@ private void setupMediaController() {
         try {
             mController = new MediaControllerCompat(this, mMediaAppDetails.sessionToken);
             mController.registerCallback(mCallback);
+            mRatingUiHelper = ratingUiHelperFor(mController.getRatingType());
 
             // Force update on connect.
             mCallback.onPlaybackStateChanged(mController.getPlaybackState());
@@ -447,9 +454,17 @@ private String fetchMediaInfo() {
             } else {
                 mMediaAlbumArtView.setImageResource(R.drawable.ic_album_black_24dp);
             }
+            // Prefer user rating, but fall back to global rating if available.
+            RatingCompat rating =
+                    mediaMetadata.getRating(MediaMetadataCompat.METADATA_KEY_USER_RATING);
+            if (rating == null) {
+                rating = mediaMetadata.getRating(MediaMetadataCompat.METADATA_KEY_RATING);
+            }
+            mRatingUiHelper.setRating(rating);
         } else {
             mMediaArtistView.setText(R.string.media_info_default);
             mMediaAlbumArtView.setImageResource(R.drawable.ic_album_black_24dp);
+            mRatingUiHelper.setRating(null);
         }
 
         final long actions = playbackState.getActions();
@@ -525,6 +540,26 @@ private String playbackStateToName(final int playbackState) {
         }
     }
 
+    private RatingUiHelper ratingUiHelperFor(int ratingStyle) {
+        switch (ratingStyle) {
+            case RatingCompat.RATING_3_STARS:
+                return new RatingUiHelper.Stars3(mRatingViewGroup, mController);
+            case RatingCompat.RATING_4_STARS:
+                return new RatingUiHelper.Stars4(mRatingViewGroup, mController);
+            case RatingCompat.RATING_5_STARS:
+                return new RatingUiHelper.Stars5(mRatingViewGroup, mController);
+            case RatingCompat.RATING_HEART:
+                return new RatingUiHelper.Heart(mRatingViewGroup, mController);
+            case RatingCompat.RATING_THUMB_UP_DOWN:
+                return new RatingUiHelper.Thumbs(mRatingViewGroup, mController);
+            case RatingCompat.RATING_PERCENTAGE:
+                return new RatingUiHelper.Percentage(mRatingViewGroup, mController);
+            case RatingCompat.RATING_NONE:
+            default:
+                return new RatingUiHelper.None(mRatingViewGroup, mController);
+        }
+    }
+
     private void addMediaInfo(Map<String, String> mediaInfos, String key, String value) {
         if (!TextUtils.isEmpty(value)) {
             mediaInfos.put(key, value);