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

Question

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?

Answer 1

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];

Answer 2

Add this Code in ViewDidLoad() For background play. It work for me. You should try it
UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
let session:AVAudioSession = AVAudioSession.sharedInstance()
do
{
try session.setCategory(AVAudioSessionCategoryPlayback)
}
catch
{
print("Background Play Error")
}