Populating Now Playing with Objective-C

Question

Created Jan ’25

Replies 2

Boosts 0

Participants 3

Hello. I am attempting to display the music inside of my app in Now Playing. I've tried a few different methods and keep running into unknown issues. I'm new to Objective-C and Apple development so I'm at a loss of how to continue.

Currently, I have an external call to viewDidLoad upon initialization. Then, when I'm ready to play the music, I call playMusic. I have it hardcoded to play an mp3 called "1". I believe I have all the signing set up as the music plays after I exit the app. However, there is nothing in Now Playing. There are no errors or issues that I can see while the app is running. This is the only file I have in Xcode relating to this feature.

Please let me know where I'm going wrong or if there is another object I need to use!

 #import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <MediaPlayer/MediaPlayer.h>
#import <AVFoundation/AVFoundation.h>
 
@interface ViewController : UIViewController <AVAudioPlayerDelegate>
 
@property (nonatomic, strong) AVPlayer *player;
@property (nonatomic, strong) MPRemoteCommandCenter *commandCenter;
@property (nonatomic, strong) MPMusicPlayerController *controller;
@property (nonatomic, strong) MPNowPlayingSession *nowPlayingSession;
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"viewDidLoad started.");
    [self setupAudioSession];
    [self initializePlayer];
    [self createNowPlayingSession];
    [self configureNowPlayingInfo];
    NSLog(@"viewDidLoad completed.");
}
 
- (void)setupAudioSession {
    AVAudioSession *audioSession = [AVAudioSession sharedInstance];
 
    NSError *setCategoryError = nil;
    if (![audioSession setCategory:AVAudioSessionCategoryPlayback error:&setCategoryError]) {
        NSLog(@"Error setting category: %@", [setCategoryError localizedDescription]);
    } else {
        NSLog(@"Audio session category set.");
    }
 
    NSError *activationError = nil;
    if (![audioSession setActive:YES error:&activationError]) {
        NSLog(@"Error activating audio session: %@", [activationError localizedDescription]);
    } else {
        NSLog(@"Audio session activated.");
    }
}
 
- (void)initializePlayer {
    NSString *soundFilePath = [NSString stringWithFormat:@"%@/base/game/%@",[[NSBundle mainBundle] resourcePath], @"bgm/1.mp3"];
    if (!soundFilePath) {
        NSLog(@"Audio file not found.");
        return;
    }
    
    NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];
    self.player = [AVPlayer playerWithURL:soundFileURL];
    NSLog(@"Player initialized with URL: %@", soundFileURL);
}
 
- (void)createNowPlayingSession {
    self.nowPlayingSession = [[MPNowPlayingSession alloc] initWithPlayers:@[self.player]];
    NSLog(@"Now Playing Session created with players: %@", self.nowPlayingSession.players);
}
 
- (void)configureNowPlayingInfo {
    MPNowPlayingInfoCenter *infoCenter = [MPNowPlayingInfoCenter defaultCenter];
 
    CMTime duration = self.player.currentItem.duration;
    Float64 durationSeconds = CMTimeGetSeconds(duration);
    CMTime currentTime = self.player.currentTime;
    Float64 currentTimeSeconds = CMTimeGetSeconds(currentTime);
 
    NSDictionary *nowPlayingInfo = @{
        MPMediaItemPropertyTitle: @"Example Title",
        MPMediaItemPropertyArtist: @"Example Artist",
        MPMediaItemPropertyPlaybackDuration: @(durationSeconds),
        MPNowPlayingInfoPropertyElapsedPlaybackTime: @(currentTimeSeconds),
        MPNowPlayingInfoPropertyPlaybackRate: @(self.player.rate)
    };
 
    infoCenter.nowPlayingInfo = nowPlayingInfo;
    NSLog(@"Now Playing info configured: %@", nowPlayingInfo);
}
 
- (void)playMusic {
    [self.player play];
    [self createNowPlayingSession];
    [self configureNowPlayingInfo];
}
 
- (void)pauseMusic {
    [self.player pause];
    [self configureNowPlayingInfo];
}
 
@end

Boost

Answer 1

Macho Man Randy Savage OP

Feb ’25

Never used MPNowPlayingSession (I set up info/remote command center directly) but...

Maybe try setting .automaticallyPublishesNowPlayingInfo = YES; and try not setting up nowPlayingInfoCenter at all...to tell the session to get metadata from AVPlayer.

If that's not what you want or doesn't work....

Try using:

  MPNowPlayingInfoCenter *infoCenter = self.nowPlayingSession.nowPlayingInfoCenter

Instead of +defaultCenter (may be the same object, but seems cleaner to do it this way).

Also I think you may need to configure the MPRemoteCommandCenter.

   MPRemoteCommandCenter *remoteCommandCenter = self.nowPlayingSession.remoteCommandCenter;
 
   id playPauseTarget = [remoteCommandCenter.togglePlayPauseCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent *_Nonnull event)
     {
// implement
}];

When not using a "session" and just populating the info I believe it is required you configure the remote command center as well (add play/pause etc.) to get your now playing info to show up.

0

Answer 2

Engineer OP

Apple

Feb ’25

Hello @ZachPhillip, thank you for your post. If your are not managing multiple players, you can use MPNowPlayingInfoCenter in conjunction with MPRemoteCommandCenter instead of MPNowPlayingSession. Please refer to the Becoming a now playable app sample code project for implementation details.

0

	#import <Foundation/Foundation.h>
	#import <UIKit/UIKit.h>
	#import <MediaPlayer/MediaPlayer.h>
	#import <AVFoundation/AVFoundation.h>

	@interface ViewController : UIViewController <AVAudioPlayerDelegate>

	@property (nonatomic, strong) AVPlayer *player;
	@property (nonatomic, strong) MPRemoteCommandCenter *commandCenter;
	@property (nonatomic, strong) MPMusicPlayerController *controller;
	@property (nonatomic, strong) MPNowPlayingSession *nowPlayingSession;

	@end

	@implementation ViewController

	- (void)viewDidLoad {
	[super viewDidLoad];
	NSLog(@"viewDidLoad started.");
	[self setupAudioSession];
	[self initializePlayer];
	[self createNowPlayingSession];
	[self configureNowPlayingInfo];
	NSLog(@"viewDidLoad completed.");
	}

	- (void)setupAudioSession {
	AVAudioSession *audioSession = [AVAudioSession sharedInstance];

	NSError *setCategoryError = nil;
	if (![audioSession setCategory:AVAudioSessionCategoryPlayback error:&setCategoryError]) {
	NSLog(@"Error setting category: %@", [setCategoryError localizedDescription]);
	} else {
	NSLog(@"Audio session category set.");
	}

	NSError *activationError = nil;
	if (![audioSession setActive:YES error:&activationError]) {
	NSLog(@"Error activating audio session: %@", [activationError localizedDescription]);
	} else {
	NSLog(@"Audio session activated.");
	}
	}

	- (void)initializePlayer {
	NSString *soundFilePath = [NSString stringWithFormat:@"%@/base/game/%@",[[NSBundle mainBundle] resourcePath], @"bgm/1.mp3"];
	if (!soundFilePath) {
	NSLog(@"Audio file not found.");
	return;
	}

	NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];
	self.player = [AVPlayer playerWithURL:soundFileURL];
	NSLog(@"Player initialized with URL: %@", soundFileURL);
	}

	- (void)createNowPlayingSession {
	self.nowPlayingSession = [[MPNowPlayingSession alloc] initWithPlayers:@[self.player]];
	NSLog(@"Now Playing Session created with players: %@", self.nowPlayingSession.players);
	}

	- (void)configureNowPlayingInfo {
	MPNowPlayingInfoCenter *infoCenter = [MPNowPlayingInfoCenter defaultCenter];

	CMTime duration = self.player.currentItem.duration;
	Float64 durationSeconds = CMTimeGetSeconds(duration);
	CMTime currentTime = self.player.currentTime;
	Float64 currentTimeSeconds = CMTimeGetSeconds(currentTime);

	NSDictionary *nowPlayingInfo = @{
	MPMediaItemPropertyTitle: @"Example Title",
	MPMediaItemPropertyArtist: @"Example Artist",
	MPMediaItemPropertyPlaybackDuration: @(durationSeconds),
	MPNowPlayingInfoPropertyElapsedPlaybackTime: @(currentTimeSeconds),
	MPNowPlayingInfoPropertyPlaybackRate: @(self.player.rate)
	};

	infoCenter.nowPlayingInfo = nowPlayingInfo;
	NSLog(@"Now Playing info configured: %@", nowPlayingInfo);
	}

	- (void)playMusic {
	[self.player play];
	[self createNowPlayingSession];
	[self configureNowPlayingInfo];
	}

	- (void)pauseMusic {
	[self.player pause];
	[self configureNowPlayingInfo];
	}

	@end

	MPRemoteCommandCenter *remoteCommandCenter = self.nowPlayingSession.remoteCommandCenter;

	id playPauseTarget = [remoteCommandCenter.togglePlayPauseCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent *_Nonnull event)
	{
	// implement
	}];