当 AVQueuePlayer 完成最后一个 playeritem 时如何做某事 [英] How to do something when AVQueuePlayer finishes the last playeritem

问题描述

我有一个 AVQueuePlayer，我正在从 4 个 AVPlayerItems 的数组中创建它，并且一切正常.

I've got an AVQueuePlayer which I'm creating from an array of 4 AVPlayerItems, and it all plays fine.

我想在队列中的最后一项播放完毕后做一些事情，我在这里查看了大量答案，这是我想要的最有希望的答案:执行代码的最佳方式声音播放完毕

I want to do something when the last item in the queue finishes playing, I've looked a load of answers on here and this is the one that looks most promising for what I want: The best way to execute code AFTER a sound has finished playing

在我的按钮处理程序中，我有这个代码:

In my button handler i have this code:

static const NSString *ItemStatusContext;

    [thePlayerItemA addObserver:self forKeyPath:@"status" options:0 context:&ItemStatusContext];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(playerItemDidReachEnd)
                                                 name:AVPlayerItemDidPlayToEndTimeNotification
                                               object:thePlayerItemA];

     theQueuePlayer = [AVQueuePlayer playerWithPlayerItem:thePlayerItemA]; 

    [theQueuePlayer play];

然后我有一个函数来处理 playerItemDidReachEnd:

and then I have a function to handle playerItemDidReachEnd:

- (void)playerItemDidReachEnd:(NSNotification *)notification {
// Do stuff here
NSLog(@"IT REACHED THE END");
}

但是当我运行这个时，我得到一个内部不一致异常:

But when I run this I get an Internal Inconsistency Exception:

    An -observeValueForKeyPath:ofObject:change:context: message was received but not handled.
Key path: status
Observed object: <AVPlayerItem: 0x735a130, asset = <AVURLAsset: 0x73559c0, URL = file://localhost/Users/mike/Library/Application%20Support/iPhone%20Simulator/5.0/Applications/A0DBEC13-2DA6-4887-B29D-B43A78E173B8/Phonics%2001.app/yes.mp3>>
Change: {
    kind = 1;

}

我做错了什么?

推荐答案

这种方法似乎对我有用，在我的按钮处理程序中，我有很多东西可以为我想播放的 4 个 mp3 文件创建 URL，然后:

This approach seems to work for me, within my button handler i've got a bunch of stuff to create URLs for the 4 mp3 files I want to play, then:

AVPlayerItem *thePlayerItemA = [[AVPlayerItem alloc] initWithURL:urlA];
AVPlayerItem *thePlayerItemB = [[AVPlayerItem alloc] initWithURL:urlB];
AVPlayerItem *thePlayerItemC = [[AVPlayerItem alloc] initWithURL:urlC];    
AVPlayerItem *thePlayerItemD = [[AVPlayerItem alloc] initWithURL:urlD];  

NSArray *theItems = [NSArray arrayWithObjects:thePlayerItemA, thePlayerItemB, thePlayerItemC, thePlayerItemD, nil];
theQueuePlayer = [AVQueuePlayer queuePlayerWithItems:theItems];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(playerItemDidReachEnd:)
                                             name:AVPlayerItemDidPlayToEndTimeNotification
                                           object:[theItems lastObject]];
[theQueuePlayer play];

之后我实现了playerItemDidReachEnd"选择器，如下所示:

After which I have implement the 'playerItemDidReachEnd' selector like this:

- (void)playerItemDidReachEnd:(NSNotification *)notification {
    // Do stuff here
    NSLog(@"IT REACHED THE END");
}

这会将 4 个 MP3 文件排入队列，然后当最后一段音频结束时，它会调用选择器，并且我的消息会出现在控制台中.

This queues up the 4 MP3 files and then when the last piece of audio has finished it calls the selector and my message appears in the console.

我希望这对其他人有用.

I hope that this is useful for someone else.

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