Question

我在这个问题上挣扎了很久但却无法找到任何解决方案

我遇到的问题是，当我暂停音频播放器时，我希望视图暂停更新，因此我使用计时器无效暂停视图加载但当我恢复播放时只恢复Audioplayer而不是视图导致我使计时器无效。

现在我可以从视图暂停的那一点开始恢复视图。通过再次启动计时器，我可以再次开始更新视图，但是程序将如何知道它在什么视图中被暂停并且应该从该点继续更新视图。有多个视图只显示两个代码。

 -(void)playpauseAction:(id)sender 
{
  if  

  ([audioPlayer isPlaying]){

 [sender setImage:[UIImage imageNamed:@"play.png"] forState:UIControlStateSelected];

 [audioPlayer pause];

 [timer invalidate];

  } else {

 [sender setImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];

 [audioPlayer play];

 self.timer = [NSTimer scheduledTimerWithTimeInterval:11 target:self selector:@selector(displayviewsAction:) userInfo:nil repeats:NO];
  }  

}

- (void)displayviewsAction:(id)sender

FirstViewController *viewController = [[FirstViewController alloc] init];

viewController.view.frame = CGRectMake(0, 0, 320, 480);

[self.view addSubview:viewController.view];

[self.view addSubview:toolbar];

[viewController release];

self.timer = [NSTimer scheduledTimerWithTimeInterval:23 target:self selector:@selector(secondViewController) userInfo:nil repeats:NO];

-(void)secondViewController {
SecondViewController *secondController = [[SecondViewController alloc] init];

secondController.view.frame = CGRectMake(0, 0, 320, 480);

[self.view addSubview:secondController.view]; 

[self.view addSubview:toolbar];

[secondController release];

self.timer = [NSTimer scheduledTimerWithTimeInterval:27 target:self selector:@selector(ThirdviewController) userInfo:nil repeats:NO];
}

感谢您的回答，并帮助我解决这个问题。

Answer 1

使用后台线程基本上将视图绑定到播放器，如下所示：

UIImageView* imageView;   //the view that gets updated

int current_selected_image_index = 0;
float time_for_next_image = 0.0;

AVAudioPlayer* audioPlayer;

NSArray* image_times;   //an array of float values representing each 
                        //time when the view should update

NSArray* image_names;   //an array of the image file names 

-(void)update_view
{
    UIImage* next_image_to_play = [image_names objectAtIndex:current_selected_image_index];
    imageView.image = next_image_to_play;
}

-(void)bind_view_to_audioplayer
{
    while(audioPlayer.isPlaying)
    {
        float currentPlayingTime = (float)audioPlayer.currentTime;
        if(currentPlayingTime >= time_for_next_image)
        {
            current_selected_image_index++;
            [self performSelectorOnMainThread:@selector(update_view) withObject:nil waitUntilDone:NO];
            time_for_next_image = [image_times objectAtIndex:[current_selected_image_index+1)];
        }
        [NSThread sleep:0.2];
    }
}

-(void)init_audio
{
current_selected_image_index = 0;
time_for_next_image = [image_times objectAtIndex:1];
 } 

-(void)play_audio
{
    [audioPlayer play];
    [self performSelectorInBackground:@selector(bind_view_to_audioplayer) withObject:nil];
}

-(void)pause_audio
{
    [audioPlayer pause];
    //that's all, the background thread exits because audioPlayer.isPlaying == NO
    //the value of current_selected_image_index stays where it is, so [self play_audio] picks up 
    //where it left off.
}

另外，当audioplayer完成播放时，添加self作为audioPlayerDidFinishPlaying:successfully:通知的观察者以重置。

恢复AVAudioplayer时如何恢复更新视图

1 个答案: