How to update volume bar in MinimalMediaRouteProvider

Question

I am using registerMediaRouteProvider and it gives you a volume bar to update the tv's volume. I implemented MediaRouteAdapter and when I scrub the volume bar, the volume changes, but the volume bar's ui always resets back to 0. How do I update the ui of the volume bar when the volume changes?

@Override
public void onCreate(Bundle savedInstanceState) {

  mCastContext = new CastContext(getApplicationContext());
  MediaRouteHelper.registerMinimalMediaRouteProvider(mCastContext, this);
  mMediaRouter = MediaRouter.getInstance(getApplicationContext());
  mMediaRouteSelector = MediaRouteHelper.buildMediaRouteSelector(MediaRouteHelper.CATEGORY_CAST);
  mMetaData = new ContentMetadata();

  mMediaRouterCallback = new MyMediaRouterCallback();
  mMediaRouteButton.setRouteSelector(mMediaRouteSelector);
}

private class MyMediaRouterCallback extends MediaRouter.Callback {
    @Override
    public void onRouteSelected(MediaRouter router, RouteInfo route) {
        MediaRouteHelper.requestCastDeviceForRoute(route);
    }

    @Override
    public void onRouteUnselected(MediaRouter router, RouteInfo route) {
        try {
            if (mSession != null) {
                Log.e(TAG, "Ending session and stopping application");
                mSession.setStopApplicationWhenEnding(true);
                mSession.endSession();
            } else {
                Log.e(TAG, "onRouteUnselected: mSession is null");
            }
        } catch (IllegalStateException e) {
            Log.e(TAG, "onRouteUnselected:");
            e.printStackTrace();
        } catch (IOException e) {
            Log.e(TAG, "onRouteUnselected:");
            e.printStackTrace();
        }
        mSelectedDevice = null;
    }
}

 @Override
public void onDeviceAvailable(CastDevice device, String arg1, MediaRouteStateChangeListener listener) {
    mSelectedDevice = device;
    openSession();
}

@Override
public void onSetVolume(double volume) {
    try {
        if (mMessageStream != null) {
            mMessageStream.setVolume(volume);
        }
    } catch (IllegalStateException e) {
        Log.e(TAG, "Problem sending Set Volume", e);
    } catch (IOException e) {
        Log.e(TAG, "Problem sending Set Volume", e);
    }
}

@Override
public void onUpdateVolume(double volumeChange) {
    try {
        if (mCurrentRoute != null) {
            mCurrentRoute.requestUpdateVolume((int) (volumeChange * 20));
        }
    } catch (IllegalStateException e) {
        Log.e(TAG, "Problem sending Update Volume", e);
    }
}

EDIT - added where I initialize mMessageStream

private void openSession() {
        mSession = new ApplicationSession(mCastContext, mSelectedDevice);
        int flags = 0;
        flags |= ApplicationSession.FLAG_DISABLE_NOTIFICATION;
        flags |= ApplicationSession.FLAG_DISABLE_LOCK_SCREEN_REMOTE_CONTROL;
        mSession.setApplicationOptions(flags);

        Log.d(TAG, "Beginning session with context: " + mCastContext);
        Log.d(TAG, "The session to begin: " + mSession);
        mSession.setListener(new com.google.cast.ApplicationSession.Listener() {

            @Override
            public void onSessionStarted(ApplicationMetadata appMetadata) {
                Log.d(TAG, "Getting channel after session start");
                ApplicationChannel channel = mSession.getChannel();
                if (channel == null) {
                    Log.e(TAG, "channel = null");
                    return;
                }
                Log.d(TAG, "Creating and attaching Message Stream");
                mMessageStream = new MediaProtocolMessageStream();
                channel.attachMessageStream(mMessageStream);

                if (mMessageStream.getPlayerState() == null) {
                    if (vastVideoView.getPlayingPlaylistItem() != null) {
                        loadMedia();
                    }
                } else {
                    Log.e(TAG, "Found player already running; updating status");
                }
            }

            @Override
            public void onSessionStartFailed(SessionError error) {
                Log.e(TAG, "onStartFailed " + error + " code " + error.getCode());
                nowifi.setVisibility(View.GONE);
            }

            @Override
            public void onSessionEnded(SessionError error) {
                Log.i(TAG, "onEnded " + error);
                controller.removeChromeCastListener();
                controller.setChromeCast(false);
                nowifi.setVisibility(View.GONE);
            }
        });

        try {
            Log.e(TAG, "Starting session with app name " + getString(R.string.app_id));
            mSession.startSession(getString(R.string.app_id));

            vastVideoView.stopPlayback();

            controller = vastVideoView.getMediaController();
            controller.setChromeCast(true);
            controller.setPausePlayListener(pausePlayListener);
            seekBar = controller.getSeekBar();
            seekBar.setProgress(0);

            mPlayButtonShowsPlay = true;
        } catch (IOException e) {
            Log.e(TAG, "Failed to open session", e);
            controller.removeChromeCastListener();
            controller.setChromeCast(false);
            nowifi.setVisibility(View.GONE);
        }
    }

Answer 1

I've been looking for this for days and I suddenly found the solution by myself :P

First, You will need a MediaRouteStateChangeListener to handle this.

MediaRouteStateChangeListener mRouteStateListener;

Second, assign the listener in onDeviceAvailable.

@Override
public void onDeviceAvailable(CastDevice device, String arg1, MediaRouteStateChangeListener listener) {
    mSelectedDevice = device;
    mRouteStateListener = listener;
    openSession();
}

Last, call MediaRouteStateListener.onVolumeChanged() in onSetVolume or onUpdateVolume.

@Override
public void onSetVolume(double volume) {
    try {
        if (mMessageStream != null) {
            mMessageStream.setVolume(volume);
            mRouteStateListener.onVolumeChanged(volume);
        }
    } catch (IllegalStateException e) {
        Log.e(TAG, "Problem sending Set Volume", e);
    } catch (IOException e) {
        Log.e(TAG, "Problem sending Set Volume", e);
    }
}

This should help your volume seekbar to act normally. :)

Answer 2

At the Receiver level, there are two ways to set the volume:

1. cast.Receiver.Platform.setVolume([0.0,1.0]) This will set the volume and show the blue bar. This is what is usually called by the onVolume message.

2. mediaElement.volume = [0.0, 1.0]; This will set the volume without showing the blue bar. You can use this for fade in / fade out, and for equalization.

Now on to your Java code: I don't see how you are getting your messageStream in what you've posted, but since it's likely to be the right thing. Here's the lines from the reference docs:

public final MediaProtocolCommand setVolume (double volume)

Sets the audio volume. Parameters volume The volume, in the range 0.0 (0%) to 1.0 (100%). Returns The command object for this request Throws IOException If an I/O error occurs while sending the message. IllegalStateException If this stream is not attached to a connected channel.