iOS volume button press detect & bluetooth headset play / next / prev / volume button, change song info display

prepare a mp3 file for testing

here is the source code:

AppDelegate, default

ViewController.h 改成這樣

	#import <UIKit/UIKit.h>
	#import <MediaPlayer/MediaPlayer.h>
	#import <AVFoundation/AVFoundation.h>
	#import <CoreBluetooth/CoreBluetooth.h>
	@interface ViewController : UIViewController
	{
	int volumecount;
	AVAudioPlayer *audioPlayer;
	NSMutableDictionary *songInfo;
	}
	@end

view raw gistfile1.m hosted with ❤ by GitHub

如果需要背景也能播放 改一下plist

ViewController.m 改成這樣，以便接收藍芽事件

	- (void)viewDidAppear:(BOOL)animated {
	[super viewDidAppear:animated];
	// Turn on remote control event delivery
	[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
	// Set itself as the first responder
	[self becomeFirstResponder];
	}

view raw gistfile2.m hosted with ❤ by GitHub

ViewController.m 改成這樣，以多緒播放音樂，監聽音量事件，並設定曲目資訊

	- (void)viewDidLoad {
	[super viewDidLoad];
	//以多執行續播放音樂 達成背景執行程式
	dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
	dispatch_async(queue, ^{
	// 設定可以背景播放音樂
	AVAudioSession *session = [AVAudioSession sharedInstance];
	if ([session setCategory:AVAudioSessionCategoryPlayback error:nil]) {
	NSLog(@"背景播放設定OK");
	} else {
	NSLog(@"背景播放設定失敗");
	}
	// 以下為播放音樂的程式碼
	NSString *filePath = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"mp3"];
	NSData *fileData = [NSData dataWithContentsOfFile:filePath];
	audioPlayer = [[AVAudioPlayer alloc] initWithData:fileData error:nil];
	[audioPlayer setVolume:0.2];
	[audioPlayer setNumberOfLoops:-1];
	if (audioPlayer != nil) {
	if ([audioPlayer prepareToPlay])
	[audioPlayer play];
	}
	});
	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(volumeChanged:) name:@"AVSystemController_SystemVolumeDidChangeNotification" object:nil];
	songInfo = [ [NSMutableDictionary alloc] init];
	[songInfo setObject: @"Audio Title" forKey:MPMediaItemPropertyTitle ];
	[songInfo setObject: @"Audio Author" forKey:MPMediaItemPropertyArtist ];
	[songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	}

view raw 3.m hosted with ❤ by GitHub

ViewController.m 改成這樣，音量改變時，改變曲目資訊

	-(void)volumeChanged:(NSNotification *)notification
	{
	float volume=[[[notification userInfo] objectForKey:@"AVSystemController_AudioVolumeNotificationParameter"]floatValue];
	NSLog(@"volume = %f",volume);
	NSString* str = [NSString stringWithFormat:@"%f",volume];
	[ songInfo setObject: str forKey:MPMediaItemPropertyTitle ];
	[ songInfo setObject: @"volume" forKey:MPMediaItemPropertyArtist ];
	[ songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[ [MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	}

view raw 4.m hosted with ❤ by GitHub

ViewController.m 改成這樣，接收到事件，改變曲目資訊

	- (void)remoteControlReceivedWithEvent:(UIEvent *)receivedEvent {
	if (receivedEvent.type == UIEventTypeRemoteControl) {
	switch (receivedEvent.subtype) {
	case UIEventSubtypeRemoteControlPlay:
	NSLog(@"play");
	[ songInfo setObject: @"play" forKey:MPMediaItemPropertyTitle ];
	[ songInfo setObject: @"Audio Author" forKey:MPMediaItemPropertyArtist ];
	[ songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[ [MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	break;
	case UIEventSubtypeRemoteControlPause:
	NSLog(@"pause");
	[ songInfo setObject: @"pause" forKey:MPMediaItemPropertyTitle ];
	[ songInfo setObject: @"Audio Author" forKey:MPMediaItemPropertyArtist ];
	[ songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[ [MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	break;
	case UIEventSubtypeRemoteControlTogglePlayPause:
	//[self playOrStop: nil];
	NSLog(@"play pause/play2");
	break;
	case UIEventSubtypeRemoteControlPreviousTrack:
	//[self previousTrack: nil];
	NSLog(@"play previous");
	[ songInfo setObject: @"previous" forKey:MPMediaItemPropertyTitle ];
	[ songInfo setObject: @"Audio Author" forKey:MPMediaItemPropertyArtist ];
	[ songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[ [MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	break;
	case UIEventSubtypeRemoteControlNextTrack:
	//[self nextTrack: nil];
	NSLog(@"play next");
	[ songInfo setObject: @"next" forKey:MPMediaItemPropertyTitle ];
	[ songInfo setObject: @"Audio Author" forKey:MPMediaItemPropertyArtist ];
	[ songInfo setObject: @"Audio Album" forKey:MPMediaItemPropertyAlbumTitle ];
	[ [MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo ];
	break;
	default:
	break;
	}
	}
	}

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