如何使Progressbar（UISlider）在我的应用程序中动态工作？ [英] How to make the Progressbar(UISlider) work dynamically in my app?

问题描述

可能重复：

UISlider控制AVAudioPlayer

我正在努力开发一个简单的iPhone的音频播放器应用程序，我需要实现必须根据歌曲（mediafile）长度运行的进度条。我怎么能完成这个？我可以使用带计时器的滑块吗？
提前感谢任何帮助，谢谢。

I'm trying to develop a simple audio player app for iPhone,i need to implement the progress bar which has to run according to song(mediafile) length.How can i accomplish this?can i use slider with timer? Any help is appreciated in advance, Thank You.

推荐答案

如果你用<$ c播放你的音频$ c> AVPlayer 然后你可以使用它的 ** addPeriodicTimeObserverForInterval **：方法来更新你的UISlider。例如，如果滑块的名称是 playerScrubber ：

If you're playing your audio with AVPlayer then you can use its **addPeriodicTimeObserverForInterval**: method to update your UISlider. For example, if the name of your slider is playerScrubber:

    AVPlayerItem *newPlayerItem = [[AVPlayerItem alloc] initWithAsset:<your asset>];
    AVPlayer* player = [[AVPlayer alloc] initWithPlayerItem:newPlayerItem];

    CMTime interval = CMTimeMake(33, 1000);  // 30fps
    id playbackObserver = [player addPeriodicTimeObserverForInterval:interval queue:dispatch_get_current_queue() usingBlock: ^(CMTime time) {
            CMTime endTime = CMTimeConvertScale (player.currentItem.asset.duration, player.currentTime.timescale, kCMTimeRoundingMethod_RoundHalfAwayFromZero);
            if (CMTimeCompare(endTime, kCMTimeZero) != 0) {
                    double normalizedTime = (double) player.currentTime.value / (double) endTime.value;
                    playerScrubber.value = normalizedTime;
            }
        }];

以后当你完成时：

[player removeTimeObserver:playbackObserver];

Goodluck！

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