在iOS 6.0中，从应用后台到前台的视频播放从暂停到播放需要2秒的延迟

Question

我有可以播放视频的VideoController。现在在navigationController中推送了VideoController。

 VideoController *ObjVideoController = [[VideoController alloc] init];
 ObjVideoController.strVideoURL = [AnimationArr objectAtIndex:SequenceCount];
 [self.navigationController pushViewController:ObjVideoController animated:NO];
 [ObjVideoController play:[AnimationArr objectAtIndex:SequenceCount]];

VideoController中的Play method是这样的：

 - (void)play:(NSString*)videoFile {
    playbaktime = 0.0;

    NSBundle *main = [NSBundle mainBundle];
    NSURL *url = [NSURL fileURLWithPath:[[main resourcePath] stringByAppendingPathComponent:videoFile]];

    if (!self.ctl)
    {
        self.ctl = nil;
        self.ctl = [[MPMoviePlayerController alloc]init];
        [self.view addSubview:self.ctl.view];
    }
    [self.ctl prepareToPlay];
    self.ctl.contentURL = url;
    self.ctl.controlStyle = 0;
    //self.ctl.useApplicationAudioSession = NO;
    [self.ctl.view setUserInteractionEnabled:NO];
    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
        [self.ctl.view setFrame:CGRectMake(0,0,480,320)];
    else
        [self.ctl.view setFrame:CGRectMake(0,0,1024,768)];

    self.ctl.backgroundView.backgroundColor = [UIColor whiteColor];
    [self.ctl play];
}

现在已经为UIApplicationWillResignActive、UIApplicationDidBecomeActive添加了observer。它的选择器如下所示：

 -(void)Pause_Video:(NSNotification*)notification {
   Pausevideo = 1;
   playbaktime = self.ctl.currentPlaybackTime;
   [self.ctl pause];
 }

-(void)Play_Video:(NSNotification*)notification {

  if(self.ctl.loadState == MPMovieLoadStateUnknown)
  {
    [self play:self.strVideoURL];
    Pausevideo = 0;
  }
  else{
    if (self.ctl.playbackState == MPMoviePlaybackStatePaused) {
        [self.ctl play];
        Pausevideo = 0;
    } 
    else
    {
        [self.ctl setInitialPlaybackTime:playbaktime];
        [self.ctl play];
        Pausevideo = 0;
    }
   }  
  }

希望您理解的问题和帮助将被感谢。

Answer 1

你似乎每次播放前都会调用prepareToPlay，这不是必需的，只需在加载文件时调用一次即可。没有必要在暂停后调用它。

此外，您还会遇到延迟，因为通知不会立即触发。具体地说，UIApplicationDidBecomeActive只有在应用程序进入前台后才会触发。相反，您需要的是观察UIApplicationWillEnterForegroundNotification，它将在应用程序进入前台时触发，并允许您显著减少延迟。