UIApplication -beginReceivingRemoteControlEvents causes Music app to take over audio

Question

I have an app that speaks to the user and listens to the user's speech response. I've noticed that when I plug my phone into my car audio system and use the app, when my app is done speaking, it receives an interruption notification and the Music app starts playing music instead of allowing my app to continue.

This doesn't happen if the phone is not attached to an external device, and this doesn't happen the moment I plug the phone in, only when the speech stops and the phone is playing through the car. I have done some testing and determined that this behavior appears when I call the beginReceivingRemoteControlEvents method on my application. If I don't sign up for remote control events when my application loads, the problem does not occur, but I cannot display 'now playing' information for my audio or use the car's controls for controlling playback.

Has anyone found a way to listen for remote control events without forfeiting control of the device's audio playback?

score 2 · Answer 1 · answered Jun 22 '14 at 18:15

This is often caused by the car stereo rather than your iOS device. Check the stereo's manual and switch it from Audio Mode to iPod Mode (or whatever your manual names these options). Basically, your car stereo is listening for the track ended notification and using that to trigger a 'play next track' notification. This calls the MPMusicPlayer which usually picks the first track alphabetically in your device's library. It could be that there is a workaround in software but I've found that the easiest thing is to change the setting on the car stereo.

score 0 · Answer 2 · answered Sep 03 '15 at 10:50

Use the following to disable remote control events (you may have to replace togglePlayPauseCommand with playCommand, or do both):

    MPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];

    [commandCenter.togglePlayPauseCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {
        NSLog(@"toggle button pressed");
        return MPRemoteCommandHandlerStatusSuccess;
    }];

or, if you prefer to use a method instead of a block:

    [commandCenter.togglePlayPauseCommand addTarget:self action:@selector(toggleButtonAction)];

To stop:

    [commandCenter.togglePlayPauseCommand removeTarget:self];

or:

    [commandCenter.togglePlayPauseCommand removeTarget:self action:@selector(toggleButtonAction)];

You'll need to add this to the includes area of your file:

@import MediaPlayer;

UIApplication -beginReceivingRemoteControlEvents causes Music app to take over audio

2 Answers2