异步加载的MPMoviePlayerController没有时间价值 [英] Asynchronous MPMoviePlayerController load has no duration value

问题描述

我假设 initWithContentURL：方法不是异步的。我添加下面的方法做负载在后台，然后分配临时球员我的变量。

I assume that the initWithContentURL: method is not asynchronous. I added the following methods to do the load in the background and then assign the temporary player to my variable.

-(void)createPlayer {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

MPMoviePlayerController *temp = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL URLWithString:@"URLString"]];

[self performSelectorOnMainThread:@selector(passPlayer:) withObject:temp waitUntilDone:YES];

[temp release];
[pool release];
}

-(void)passPlayer:(MPMoviePlayerController*)temp {    
player = [temp retain];
player.movieSourceType = MPMovieSourceTypeStreaming;
//player.view.hidden = YES;
//[self.view addSubview:player.view];
[player prepareToPlay];
}

问题是，当我打印出来的球员，我得到这个持续时间：

The problem is when I print out the duration of the player I get this:

double duration = player.duration;
NSLog(@"duration: %f, duration);

console output:  duration: nan

我已经添加了 MPMoviePlayerControllerNotifications 当有可用的持续时间值被通知，但即使如此，该值仍然是'南'。如果我做了主线程的负载持续时间有一个值，但我不希望使用主线程，所以我的用户界面不会锁定。

I have added the MPMoviePlayerControllerNotifications to be notified when there is a duration value available, but even then the value is still 'nan'. If I do the load on the main thread the duration has a value, but I don't want to use the main thread so my UI doesn't lock up.

任何想法？

推荐答案

从官方文档：

讨论
  如果电影的持续时间是未知的，在该属性的值是0.0。如果持续时间随后确定，这个属性被更新和MPMovieDurationAvailableNotification通知发布。

Discussion If the duration of the movie is not known, the value in this property is 0.0. If the duration is subsequently determined, this property is updated and a MPMovieDurationAvailableNotification notification is posted.

因此​​，使用NSNotificationCenter注册MPMovieDurationAvailableNotification通知。

So use NSNotificationCenter to register the MPMovieDurationAvailableNotification notification.

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