[绍棠] avplayer

做视频播放，边下边播，都做了一个多月了，前前后后3套方案，最后终于算是完美的解决了。今天关于avplayer又学到了一点新的知识。

1.一般情况下需要实现的4个监听属性

//预播放状态，有三种情况AVPlayerItemStatusUnknown,AVPlayerItemStatusReadyToPlay,AVPlayerItemStatusFailed

[self.videoPlayItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];

//缓冲进度，可有可无，可以增加用户体验

[self.videoPlayItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];

//seekToTime后，缓冲数据为空，而且有效时间内数据无法补充，播放失败

[self.videoPlayItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil];

//seekToTime后,可以正常播放，相当于readyToPlay，一般拖动滑竿菊花转，到了这个这个状态菊花隐藏

[self.videoPlayItem addObserver:self forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil];

2. 一般情况下需要监听的4个通知中心

[[NSNotificationCenter defaultCenter]addObserver:self

selector:@selector(moviePlayDidEnd:)

name:AVPlayerItemDidPlayToEndTimeNotification

object:_videoPlayItem];  // 添加视频播放结束通知

[[NSNotificationCenter defaultCenter]addObserver:self

selector:@selector(moviePlayInterrupt:)

name:AVPlayerItemPlaybackStalledNotification

object:_videoPlayItem];  //添加视频异常中断通知

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(enterBcakground:)

name:UIApplicationWillResignActiveNotification

object:nil]; //进入后台

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(enterPlayGround:)

name:UIApplicationDidBecomeActiveNotification

object:nil]; // 返回前台

3. rate属性

avplayer自身有一个rate属性

rate ==1.0，表示正在播放；rate == 0.0，暂停；rate == -1.0，播放失败

为了严谨，可以这样判断播放器状态

if (avplayer.rate > 0 && avplayer.error == nil) {

//playing

} else {

//failed

}

4. slider

为了更好地用户体验，一般在滑竿滑动过程中，停止播放时间的走动，当前时间的显示随滑竿移动而改变，当手指离开滑竿后，播放器从当前点开始播放，在从当前点开始播放的时候，有可能没有缓冲数据，需要临时加载，这时候就需要掏用到上面的方法来判断当前状态，加载数据还没有播放的时候，时间走动需要停止，当开始播放了，才开始时间走动。

[_playSlider addTarget:self action:@selector(playSliderChange:) forControlEvents:UIControlEventValueChanged]; //拖动滑竿更新时间

[_playSlider addTarget:self action:@selector(playSliderChangeEnd:) forControlEvents:UIControlEventTouchUpInside];  //松手,滑块拖动停止

//在松手的时候，也有可能会走下面其中某一个时间，为了严谨，建议加上这些事件，当然，松手的时候，只可能走这3个事件中的某一个

[_playSlider addTarget:self action:@selector(playSliderChangeOutEnd:) forControlEvents:UIControlEventTouchUpOutside];

[_playSlider addTarget:self action:@selector(playSliderChangeCancel:) forControlEvents:UIControlEventTouchCancel];

5.视频播放时间显示小技巧

这样写，不管时间有多长，都可以按照  小时：分钟：秒数 的形式来显示，简单吧！

NSString *str = nil;

if (videocurrent < 3600) {

str =  [NSString stringWithFormat:@"%02li:%02li",lround(floor(videocurrent/60.f)),lround(floor(videocurrent/1.f))%60];

} else {

str =  [NSString stringWithFormat:@"%02li:%02li:%02li",lround(floor(videocurrent/3600.f)),lround(floor(videocurrent%3600)/60.f),lround(floor(videocurrent/1.f))%60];

}

6.附上比较重要的一段代码，监听事件

//kvo监听播放状态

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{

AVPlayerItem *playerItem = (AVPlayerItem *)object;

if ([keyPath isEqualToString:@"status"]) {

if ([playerItem status] == AVPlayerStatusReadyToPlay) {

CGFloat totalSecond = playerItem.duration.value / playerItem.duration.timescale;// 转换成秒

[self updateTotolTime:totalSecond];

[self setPlaySliderValue:totalSecond];

_videoLength = totalSecond;

[self monitoringPlayback:_videoPlayItem];// 监听播放状态

NSLog(@"readytoPlayreadytoPlayreadytoPlayreadytoPlay");

if ([self.delegate respondsToSelector:@selector(TBAVplayerReadyToPlay:)]) {

[self.delegate TBAVplayerReadyToPlay:self];

}

[_showView.layer addSublayer:self.videoPlayerLayer];

} else if ([playerItem status] == AVPlayerStatusFailed || [playerItem status] == AVPlayerStatusUnknown) {

if ([self.delegate respondsToSelector:@selector(TBAVPlayerPlayReadyFailed:)]) {

[self.delegate TBAVPlayerPlayReadyFailed:self];

}

}

} else if ([keyPath isEqualToString:@"loadedTimeRanges"]) {

if (_isFinishLoading || _localVideo) {

[self.videoProgressView setProgress:1 animated:NO];    //如果视频下载完成，把缓冲进度置为满格

} else {

NSTimeInterval timeInterval = [self availableDuration];// 计算缓冲进度

CMTime duration = self.videoPlayItem.duration;

CGFloat totalDuration = CMTimeGetSeconds(duration);

[self.videoProgressView setProgress:timeInterval / totalDuration animated:YES];

}

} else if (object == playerItem && [keyPath isEqualToString:@"playbackBufferEmpty"]) {

if (playerItem.playbackBufferEmpty) {

//Your code here

[_videoPlayerLayer.player pause];

[_hudHelper showHudOnView:_showView caption:nil image:nil acitivity:YES autoHideTime:0];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

[_videoPlayerLayer.player play];

//rate 是avplayer 是一个属性，rate 1.0表示正在播放，0.0暂停， -1播放器失效

if (self.rate <= 0) {

[[iToast makeText:@"播放异常"] show];

}

});

}

} else if (object == playerItem && [keyPath isEqualToString:@"playbackLikelyToKeepUp"])

{

if (playerItem.playbackLikelyToKeepUp)

{

_playState = YES;

//Your code here拖动之后开始播放

[_hudHelper hideHud];

}

}

}