使用AVAudioSession暫停和播放音頻

Question

我有1個控制器。 首先，我開始播放audio1。 我使用以下代碼：

- (void)viewDidLoad
{

     //code to not turn off audio with using mute switch

     [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
     [[AVAudioSession sharedInstance] setActive: NO error: nil];

      //code to play audio

      NSString *soundFilePath = [NSString stringWithFormat:@"%@/%@.mp3",[[NSBundle mainBundle] resourcePath], @"sound"];
      NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];
      _player = [[AVAudioPlayer alloc] initWithContentsOfURL:soundFileURL error:nil];
      _player.numberOfLoops = -1;
      [_player play];
}

但是，當我隱藏我的應用程序音頻時，聲音不會暫停。 我想在我隱藏我的應用程序時暫停音頻，並在應用程序進入前台時在暫停點播放。 怎么做？

Answer 1

為此，您需要為應用程序添加通知，在后台和前台輸入。

首先聲明玩家

 AVAudioPlayer *player;

在ViewDidLoad中添加此代碼

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEnterBackgroundActive:) name:UIApplicationDidEnterBackgroundNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEnterForegroundActive:) name:UIApplicationWillEnterForegroundNotification object:nil];

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];

[[AVAudioSession sharedInstance] setActive: NO error: nil];

//code to play audio
NSString *soundFilePath = [NSString stringWithFormat:@"%@/%@.mp3",[[NSBundle mainBundle] resourcePath], @"alarm_tone"];
NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];
player = [[AVAudioPlayer alloc] initWithContentsOfURL:soundFileURL error:nil];
player.numberOfLoops = -1;
[player play];

添加“輸入背景”方法。

-(void)appEnterBackgroundActive:(NSNotification*)note
{
     [player pause];
}

添加Enter前景方法。

-(void)appEnterForegroundActive:(NSNotification*)note
{
    [player play];
}

Answer 2

您可以使用通知來檢測應用程序將進入背景/前景。

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEnterBackground:) name:@"enterBackGroundNotification" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEnterForeground:) name:@"enterForeGroundNotification" object:nil];

- (void)appEnterBackground:(NSNotification *) notification {
   [_player pause];
}

- (void)appEnterForeground:(NSNotification *) notification {
   [_player play];
}