IssueTracker

Component used: androidx.media2.session.MediaController

Version used: 1.1.0

Devices/Android versions reproduced on: Nexus S API 29, but it'll be same on any device.

Currently the MediaControllerImplLegacy blocks setMediaItem calls (as well as calls to setMediaUri):

@Override
public ListenableFuture<SessionResult> setMediaItem(@NonNull String mediaId) {
    return createFutureWithResult(RESULT_ERROR_NOT_SUPPORTED);
}

It's not clear why, since implementation would look exactly the same as for many of the implemented calls, i.e. for setMediaItem:

@Override
public ListenableFuture<SessionResult> setMediaItem(@NonNull String mediaId) {
    synchronized (mLock) {
        if (!mConnected) {
            Log.w(TAG, "Session isn't active", new IllegalStateException());
            return createFutureWithResult(RESULT_ERROR_SESSION_DISCONNECTED);
        }
        mControllerCompat.getTransportControls().playFromMediaId(mediaId, null);
        // or Bundle.EMPTY as a second argument, not sure if it matters
    }
    return createFutureWithResult(RESULT_SUCCESS);
}

This is very important part of API and there's no good workaround.

Could anyone please see if it'd be possible to implement this? :)