如何停止 AVPlayer Ios 并移除periodicTimeObserverForInterval

Question

我在停止 AVPlayer 时遇到了一点困难。

我有一种方法可以同时录制和播放音乐。我正在使用 AVPlayer 播放音乐，因为我想使用 addPeriodicTimeObserverForInterval 函数。我的设置如下：

    - (IBAction) recordVoice:(id)sender {
    if(!recorder.isRecording){

    //set up the file name to record to
    NSString *recordingLocation = [self createFileName];
    recordingName = recordingLocation;
    NSArray *pathComponents = [NSArray arrayWithObjects:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject],
                               recordingLocation, nil];
    NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];
    recordingURL = outputFileURL;

    // Setup audio session
    session = [AVAudioSession sharedInstance];
    [session setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker
                   error:nil];

    // Define the recording settings to record as m4a
    NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];
    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
    [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
    [recordSetting setValue:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey];

    // initiate and prepare the recorder
    recorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:NULL];
    recorder.delegate = self;
    recorder.meteringEnabled = YES;
    [recorder prepareToRecord];
    [session setActive:YES error:nil];
    [recorder record];


    // find which song to play and initiate an AVPlayer to play it
    NSString *playerLocation = self.TitleLabel.text;
    NSString *path = [[NSBundle mainBundle] pathForResource:playerLocation ofType:@"m4a"];
        player = [[AVPlayer alloc] initWithURL:[NSURL fileURLWithPath:path]];
        lastTime = nil;

    //check where the player is at and update the song lines accordingly
    [player addPeriodicTimeObserverForInterval:CMTimeMake(3, 10) queue:NULL usingBlock:^(CMTime time){
            NSTimeInterval seconds = CMTimeGetSeconds(time);
            for (NSDictionary *item in robotR33) {
                NSNumber *time = item[@"time"];
                if ( seconds > [time doubleValue] && [time doubleValue] >= [lastTime doubleValue] ) {
                    lastTime = @(seconds);
                    NSString *str = item[@"line"];
                    [self nextLine:str];
                };
            }
        }];
        [player play];

    [_recordButton setImage:[UIImage imageNamed:@"micRecording.gif"] forState:UIControlStateNormal];

    }
    else{
        [recorder stop];
        player = nil;
        [session setActive:NO error:nil];
    }   
}

如果录音机没有录音，我会同时设置一个新的录音机 AVAudioRecorder 和一个 AVPlayer。在 AVPlayer 中，我设置了一个 AddPeriodicTimeObserverForInterval，它根据玩家的位置更新 UI。

如果录音机正在录音，我会停止录音机并将播放器设置为零。这会停止播放音频，但我注意到 addPeriodicTimeObserverInterval 仍在运行，因为 UI 继续更新。我应该完全销毁 AVPlayer，如果是，我应该怎么做？非常感谢。

另外，我在 addPeriodicTimeObserverForInterval 块中有一个警告。我正在循环一个名为robotR33 的数组。 Xcode 告诉我“在此块中强烈捕获自我可能会导致保留周期”。这可能是我的问题的一部分吗？

Answer 1

播放完毕后，需要将观察者从播放器中移除。

添加[player removeTimeObserver:self.timeObserver] 有效。