我使用播放流内容的AVPlayer.我想知道缓冲区空的时间和准备播放的时间.但观察者“playbackBufferEmpty”和“playbackLikelyToKeepUp”在每次需要时都不起作用.他们有时工作但往往不工作.我在OSX 10.7.5下只使用iPad模拟器iOS 6.1.
以下是我设置和观察观察者的方式:
- (void)playAudioStream:(NSURL *)audioStreamURL
{
if(_audioPlayer && _audioPlayer.currentItem)
{
[_audioPlayer removeObserver:self forKeyPath:StatusKey];
[_audioPlayer.currentItem removeObserver:self forKeyPath:@"playbackBufferEmpty"];
[_audioPlayer.currentItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp"];
}
AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:audioStreamURL];
[playerItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil];
[playerItem addObserver:self forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil];
_audioPlayer = [AVPlayer playerWithPlayerItem:playerItem];
[_audioPlayer addObserver:self forKeyPath:StatusKey options:NSKeyValueObservingOptionNew context:nil];
//[_audioPlayer replaceCurrentItemWithPlayerItem:playerItem];
//_audioPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;
[_audioPlayer play];
}
...
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ([keyPath isEqualToString:@"playbackBufferEmpty"] )
{
if (_audioPlayer.currentItem.playbackBufferEmpty)
{
...
}
}
if ([keyPath isEqualToString:@"playbackLikelyToKeepUp"])
{
if (_audioPlayer.currentItem.playbackLikelyToKeepUp)
{
...
}
}
}
请帮助我获得“缓冲区空”和“缓冲区就绪”事件的正确方法(例如,当Internet连接断开时).谢谢!
最佳答案 添加观察者时需要使用上下文.这是您的示例代码.
初始化背景
static void *playbackLikelyToKeepUpKVOToken = &playbackLikelyToKeepUpKVOToken;
static void *playbackBufferEmpty = &playbackBufferEmpty;
static void *playbackBufferFull = &playbackBufferFull;
添加观察者
[self.playerItem removeObserver:self forKeyPath:@"playbackBufferEmpty" context:playbackBufferEmpty];
[self.playerItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp" context:playbackLikelyToKeepUpKVOToken];
[self.playerItem removeObserver:self forKeyPath:@"playbackBufferFull" context:playbackBufferFull];
处理
if (context == playbackLikelyToKeepUpKVOToken)
{
if (self.playerItem.playbackLikelyToKeepUp)
{
NSLog(@"recieve playbackLikelyToKeepUp");
}
}
else if (context == playbackBufferEmpty)
{
if (self.playerItem.playbackBufferEmpty)
{
NSLog(@"recieve playbackBufferEmpty");
}
}
else if(context == playbackBufferFull)
{
NSLog(@"recieve playbackBufferFull");
}
else
{
[super observeValueForKeyPath:path ofObject:object change:change context:context];
}