ios - 使用 NSTimer iOS Objective C 暂停/播放音频播放器

Question

我正在开发一个音乐播放器应用程序。并在播放音频时使用播放/暂停按钮和进度条。我正在调用一个带有 NSTimer 的方法来更新进度条。我需要的是暂停进度条并在停止的地方恢复它。

我可以使用链接中引用的代码暂停计时器和进度条:1. How to pause a NSTimer?2. How to Pause/Play NSTimer?

但我正在努力恢复 ii 中断的地方。我还需要根据音频更新进度条。

我的代码如下:

AVAudioPlayer *audioPlayer;
NSTimer *audioTimer;
BOOL play;

BOOL ispaused;
int seconds1;
int minutes1;
int hours1;

NSDate *pauseStart, *previousFireDate;

播放/暂停按钮操作:

- (IBAction)playSoundTapped:(id)sender
{
songUrl = [NSURL URLWithString:@"http://www.stephaniequinn.com/Music/Allegro%20from%20Duet%20in%20C%20Major.mp3"];

self.playerItem = [AVPlayerItem playerItemWithURL:songUrl];
self.player = [AVPlayer playerWithPlayerItem:self.playerItem];
self.player = [AVPlayer playerWithURL:songUrl];

if (play==YES)
{
    if (ispaused == YES)
    {
        float pauseTime = -1*[pauseStart timeIntervalSinceNow];
        [audioTimer setFireDate:[NSDate dateWithTimeInterval:pauseTime sinceDate:previousFireDate]];
        audioTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateProgress) userInfo:nil repeats:YES];

        [self.player play];

        ispaused = NO;
    }
    else
    {
        audioTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateProgress) userInfo:nil repeats:YES];

        [self.player play];

        ispaused = NO;
    }

    _playImg.image=[UIImage imageNamed:@"Pause.png"];
    play=NO;
}
else
{
    [self.player pause];

    ispaused = YES;

    pauseStart = [NSDate dateWithTimeIntervalSinceNow:0];
    previousFireDate = [audioTimer fireDate];
    [audioTimer setFireDate:[NSDate distantFuture]];

    _playImg.image=[UIImage imageNamed:@"Play.png"];
    play=YES;
}
}

更新进度条:

- (void)updateProgress
{
    if (ispaused == NO)
    {
        seconds1 += 1;

    if (seconds1 == 60)
    {
        seconds1 = 0;
        minutes1++;

        if (minutes1 == 60)
        {
            minutes1 = 0;
            hours1++;
        }
    }

    float duration = CMTimeGetSeconds([_playerItem duration]);
    float actDuration = duration/100;
    float currentTime = CMTimeGetSeconds([_player currentTime]);
    float minutes = currentTime/60;
    //float seconds = (currentTime - minutes) * 60;
    NSLog(@"Duration: %.2f",actDuration);
    NSLog(@"Current Time: %.2f",minutes);

    NSString *durStr = [NSString stringWithFormat: @"%f",duration];

    if ([durStr  isEqual: @"nan"])
    {
        NSLog(@"Nan");
    }
    else
    {
        [self setProgress:minutes animated:YES];
    }
}
else
{
      NSLog(@“Paused”);        
}
}

它正在重新启动音频而不是恢复。由于我是 iOS 的初学者，我不知道我哪里做错了。谁能帮帮我……？

Answer 1

我在我的一个项目中正在做什么，

 - (void)playPauseAudio : (UIButton*)sender{

if (!playPause.selected) {


    [audioPlayer play];

    sliderTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateSlider) userInfo:nil repeats:YES];
    [mySlider addTarget:self action:@selector(sliderChanged:) forControlEvents:UIControlEventValueChanged];
    mySlider.maximumValue = audioPlayer.duration;

}
else{

    [audioPlayer pause];
    [sliderTimer invalidate];
}



playPause.selected = !playPause.selected;

}

我有播放和暂停的通用按钮，它只是将 normal state 和 selected state 的标题更改为 play 和 分别暂停。

所以在我的方法中，playPause是button，audioPlayer是AVAudioPlayer对象，sliderTimer是 NSTimer 对象，mySlider 是UISlider 对象来显示进度。而已。您可以按照我提到的方式管理您的案例。

updateSlider 和 sliderChanged 方法如下所示，

 - (void)updateSlider{

mySlider.value = audioPlayer.currentTime;
timerLabel.text = [self timeFormatted:audioPlayer.duration - audioPlayer.currentTime];
NSLog(@"update slider call");

}

- (void)sliderChanged : (UISlider*) sender{


[audioPlayer setCurrentTime:mySlider.value];
timerLabel.text = [self timeFormatted:audioPlayer.duration - mySlider.value];


}

因此，如果用户手动更改 UISlider，则 sliderChanged 将被调用，您的播放器将到达该点。