iphone - AVAudioPlayer 当前时间问题

Question

我正在尝试将 AVAudioPlayer 与 slider 一起使用，以便进入轨道(没有什么复杂的)。

但我有一个奇怪的行为...对于 currentTime 的某个值(在 0 和 trackDuration 之间)，播放器停止播放轨道，并进入 audioPlayerDidFinishPlaying:successfully:成功地成为NO。它没有进入 audioPlayerDecodeErrorDidOccur:error:

就好像它无法读取我给它的时间。

例如轨道的持续时间是:295.784424 秒我将 currentTime 设置为 55.0s(即:54.963878 或 54.963900 或 54.987755 等...当打印为 %f 时)。当 currentTime 为 54.987755 时，“崩溃”总是发生......我真的不明白为什么......

所以如果你有任何想法...... ^^

Answer 1

我也很难让音频跳过与“AVAudioPlayer setCurrentTime:”一起正常工作

经过大量实验，我发现了一个在模拟器和设备上可靠运行的序列:(在 OS3.1+ 上测试)

// Skips to an audio position (in seconds) of the current file on the [AVAudioPlayer* audioPlayer] class instance
// This works correctly for a playing and paused audioPlayer
//
- (void) skipToSeconds:(float)position
{
    @synchronized(self) 
    {
        // Negative values skip to start of file
        if ( position<0.0f )
            position = 0.0f;

        // Rounds down to remove sub-second precision
        position = (int)position;

        // Prevent skipping past end of file
        if ( position>=(int)audioPlayer.duration )
        {
            NSLog( @"Audio: IGNORING skip to <%.02f> (past EOF) of <%.02f> seconds", position, audioPlayer.duration );
            return;
        }

        // See if playback is active prior to skipping
        BOOL skipWhilePlaying = audioPlayer.playing;

        // Perform skip
        NSLog( @"Audio: skip to <%.02f> of <%.02f> seconds", position, audioPlayer.duration );

        // NOTE: This stop,set,prepare,(play) sequence produces reliable results on the simulator and device.
        [audioPlayer stop];
        [audioPlayer setCurrentTime:position];
        [audioPlayer prepareToPlay];

        // Resume playback if it was active prior to skipping
        if ( skipWhilePlaying )
            [audioPlayer play];
    }
}