AVAudioSessionInterruptionNotification未正确调用

我正在制作一个音频流媒体应用程序,我遇到了中断问题.我已经读过我应该使用AVAudioSessionInterruptionNotification,但我的问题是它只在中断开始时被调用,而不是在它结束时被调用.这是我的代码.

static dispatch_once_t pred;
static Player *sharedAudioPlayer = nil;
dispatch_once(&pred, ^
              {
                  sharedAudioPlayer = [[self alloc] init];

                  [[NSNotificationCenter defaultCenter] addObserver:sharedAudioPlayer selector:@selector(playerItemDidFinishPlaying:) name:AVPlayerItemDidPlayToEndTimeNotification object:nil];
                  [[NSNotificationCenter defaultCenter] addObserver:sharedAudioPlayer
                                                           selector:@selector(audioSessionInterrupted:)
                                                               name:AVAudioSessionInterruptionNotification
                                                             object:audioSession];
              });

然后

- (void)audioSessionInterrupted:(NSNotification*)notification {
NSDictionary *interruptionDictionary = [notification userInfo];
NSNumber *interruptionType = (NSNumber *)[interruptionDictionary valueForKey:AVAudioSessionInterruptionTypeKey];
if ([interruptionType intValue] == AVAudioSessionInterruptionTypeBegan) {
    NSLog(@"Interruption started");
    if (self.delegate && [self.delegate respondsToSelector:@selector(playerWasPaused)]) {
        [self.delegate playerWasPaused];
    }
} else if ([interruptionType intValue] == AVAudioSessionInterruptionTypeEnded){
    NSLog(@"Interruption ended");
    [player play];
} else {
    NSLog(@"Something else happened");
}

当一个电话开始时,我打印两次"中断开始",但是当它结束时我什么都没得到.我甚至试图检查是否有其他内容发送到通知但仍然没有.有任何想法吗？