使用 NSTimer 暂停/播放音频播放器 iOS Objective C

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 Play/Pause 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;

Play/Pause 按钮动作：

- (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 上的标题分别更改为 play 和 pause。

所以在我的方法中，playPause是按钮，audioPlayer是AVAudioPlayerobject，sliderTimer是NSTimerobject, mySlider 就是 UISlider object 来表示进度。就是这样。您可以按照我提到的方式管理您的案件。

和updateSlider和sliderChanged方法如下，

 - (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，那么 sliderChanged 将被调用，您的播放器将到达该点。

Answer 2

我明白了！

我只是在暂停功能中添加以下内容

rate = CMTimeGetSeconds([_player currentTime])/60;

并参考 ketan Parmer 的回答

将其设置为音频播放器的当前时间

[audioPlayer setCurrentTime:rate];

停止时

rate = 0.0;

并且 rate 是一个全局声明的浮点数。感谢 Ketan..!

使用 NSTimer 暂停/播放音频播放器 iOS Objective C

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