没有AVPlayer代表？歌曲播放完毕后如何追踪？ Objective C iPhone开发 [英] No AVPlayer Delegate? How to track when song finished playing? Objective C iPhone development

问题描述

我环顾四周但是找不到 AVPlayer类的委托协议。给出了什么？

I've looked around but I can't find a delegate protocol for the AVPlayer class. What gives?

我正在使用它的子类 AVQueuePlayer 来播放 AVPlayerItems ，每个都从URL加载。有什么方法可以在歌曲播放完毕后调用方法吗？特别是在队列的最后？

I'm using its subclass, AVQueuePlayer, to play an array of AVPlayerItems, each loaded from a URL. Is there any way I can call a method when a song finishes playing? Notably at the end of the queue?

如果那不可能，有什么办法可以在歌曲STARTS播放后调用方法，缓冲后？我正试图在那里获得一个加载图标，但它在音乐实际开始之前关闭了图标，即使它是在 [audioPlayer play] 动作之后。

And if that's not possible, is there any way I could call a method when the song STARTS playing, after buffering? I'm trying to get a loading icon in there but it turns the icon off before the music actually begins, even though it's after the [audioPlayer play] action.

推荐答案

是的，AVPlayer类没有像AVAudioPlayer这样的委托协议。您需要订阅AVPlayerItem上的通知。您可以使用在AVPlayer上传递给 -initWithURL：的相同URL创建AVPlayerItem。

Yes, the AVPlayer class does not have a delegate protocol like the AVAudioPlayer. You need to subscribe to notifications on an AVPlayerItem. You can create an AVPlayerItem using the same URL that you would otherwise pass to -initWithURL: on AVPlayer.

-(void)startPlaybackForItemWithURL:(NSURL*)url {

    // First create an AVPlayerItem
    AVPlayerItem* playerItem = [AVPlayerItem playerItemWithURL:url];

    // Subscribe to the AVPlayerItem's DidPlayToEndTime notification.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(itemDidFinishPlaying:) name:AVPlayerItemDidPlayToEndTimeNotification object:playerItem];

    // Pass the AVPlayerItem to a new player
    AVPlayer* player = [[[AVPlayer alloc] initWithPlayerItem:playerItem] autorelease];

    // Begin playback
    [player play]

} 

-(void)itemDidFinishPlaying:(NSNotification *) notification {
    // Will be called when AVPlayer finishes playing playerItem
}

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