Why do the Lock Screen audio controls disappear when I pause AVAudioPlayer?

audio, avaudioplayer, ios, objective-c, uievent

Solution

You're on the right track ...

You seem to be missing setting;

  MPNowPlayingInfoCenter nowPlayingInfo

Without it, you will get the results described, IE after pressing pause, the lock screen no longer shows the pause, or indeed that it is playing a song. Here's a guide on how to set it (i've taken this from working code I did some time back, but I'm sure you can figure out what's what).

    MPMediaItemArtwork *artwork = [[MPMediaItemArtwork alloc]initWithImage:albumImage];
    [MPNowPlayingInfoCenter defaultCenter].nowPlayingInfo = [NSDictionary dictionaryWithObjectsAndKeys:aSong.songTitle, MPMediaItemPropertyTitle,
                                                             aSong.artistName, MPMediaItemPropertyArtist, artwork, MPMediaItemPropertyArtwork,  1.0f, MPNowPlayingInfoPropertyPlaybackRate, nil];

Problem

I'm using an instance of AVAudioPlayer to play an audio file. The app is configured to play audio in the background and an appropriate audio session is set. I am also successfully receiving remote control events. Here's the code: ``` #import "ViewController.h" #import <AVFoundation/AVFoundation.h> @interface ViewController () @property (nonatomic) AVAudioPlayer *player; @end @implementation ViewController @synthesize player; - (BOOL)canBecomeFirstResponder { return YES; } - (void)viewDidLoad { [super viewDidLoad]; // Turn on remote control event delivery [[UIApplication sharedApplication] beginReceivingRemoteControlEvents]; // Set ourselves as the first responder [self becomeFirstResponder]; // Set the audio session AVAudioSession *audioSession = [AVAudioSession sharedInstance]; NSError *setCategoryError = nil; BOOL success = [audioSession setCategory:AVAudioSessionCategoryPlayback error:&setCategoryError]; NSError *activationError = nil; success = [audioSession setActive:YES error:&activationError]; // Play an mp3 with AVAudioPlayer NSString *audioFileName = @"%@/Via_Aurora.mp3"; NSURL *audioURL = [NSURL fileURLWithPath:[NSString stringWithFormat:audioFileName, [[NSBundle mainBundle] resourcePath]]]; player = [[AVPlayer alloc] initWithURL:audioURL]; [player play]; } - (void)viewWillDisappear:(BOOL)animated { // Turn off remote control event delivery & Resign as first responder [[UIApplication sharedApplication] endReceivingRemoteControlEvents]; [self resignFirstResponder]; // Don't forget to call super [super viewWillDisappear:animated]; } - (void)remoteControlReceivedWithEvent:(UIEvent *)receivedEvent { if (receivedEvent.type == UIEventTypeRemoteControl) { switch (receivedEvent.subtype) { case UIEventSubtypeRemoteControlPreviousTrack: NSLog(@"prev"); break; case UIEventSubtypeRemoteControlNextTrack: NSLog(@"next"); break; case UIEventSubtypeRemoteControlPlay: [player play]; break; case UIEventSubtypeRemoteControlPause: [player pause]; break; default: break; } } } @end ``` When I run the app the audio plays when the view loads. The app continues to play audio when it goes into background mode. I am able to successfully pause and/or play audio from the Control Center (accessed either from within the app or the Lock Screen) but, if I access the Lock Screen audio controls and pause the player, the music pauses and the lock screen controls disappear. I expect the music to pause, but not for the controls to disappear. In other audio apps that I use you can pause, then play, audio from the Lock Screen. Have I overlooked something? Is this a correct approach to do something like this?

Original source