暂停UIImageview动画

Question

我想暂停,UIImageView animation并根据我的研究发现,你可以停止图像的动画,但你不能暂停序列.通过调用语句stop animating上UIImageView,然后它停止动画,显示空白图像视图.

要暂停UIImages的动画,必须使用NSTimer.

我已经NSTimer在应用程序中使用一个view controllers以不同的时间间隔一个接一个地加载.我UIImages每个都有幻灯片view controller.

问题是当暂停计时器暂停view controllers进一步加载但当时view controller显示的那个仍然重复显示幻灯片UIImages,view controller直到恢复暂停.所以我想暂停那个幻灯片.

这是我使用的地方 NSTimer

-(void)playpauseAction:(id)sender {
if([audioPlayer isPlaying])
{
    [sender setImage:[UIImage imageNamed:@"Play Icon.png"] forState:UIControlStateSelected];
    [audioPlayer pause];
    [self pauseTimer];
}else{
    [sender setImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
    [audioPlayer play];
    [self resumeTimer];
if(isFirstTime == YES)
    {
     self.timer = [NSTimer scheduledTimerWithTimeInterval:11.0
                                         target:self
                                         selector:@selector(displayviewsAction:)
                                         userInfo:nil
                                        repeats:NO];
        isFirstTime  = NO;
    }         
    } 
    }

这就是displayviewsAction以不同的时间间隔一个接一个地加载11个视图控制器的方式

- (void)displayviewsAction:(id)sender
 {  
 First *firstController = [[First alloc] init];
 firstController.view.frame = CGRectMake(0, 0, 320, 480);
 CATransition *transitionAnimation = [CATransition animation];
 [transitionAnimation setDuration:1];
 [transitionAnimation setType:kCATransitionFade];
 [transitionAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]];
 [self.view.layer addAnimation:transitionAnimation forKey:kCATransitionFade];
 [self.view addSubview:firstController.view];
 [self.view addSubview:toolbar];
 [firstController release];   
 self.timer = [NSTimer scheduledTimerWithTimeInterval:23 target:self selector:@selector(Second) userInfo:nil repeats:NO];     

 }

 -(void)Second 
{
Second *secondController = [[Second alloc] init];
secondController.view.frame = CGRectMake(0, 0, 320, 480);
CATransition *transitionAnimation = [CATransition animation];
[transitionAnimation setDuration:1];
[transitionAnimation setType:kCATransitionReveal];
[transitionAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]];
[self.view.layer addAnimation:transitionAnimation forKey:kCATransitionReveal];
[self.view addSubview:secondController.view]; 
[self.view addSubview:toolbar];
[secondController release];
self.timer = [NSTimer scheduledTimerWithTimeInterval:27 target:self selector:@selector(Third) userInfo:nil repeats:NO];
}

这就是如何在视图控制器中启动图像动画

// Displays UIImageView
UIImageView* ImageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 5, 300, 235)];
self.view.backgroundColor = [UIColor brownColor];
// load all the frames of our animation
ImageView.animationImages = [NSArray arrayWithObjects:    
                                [UIImage imageNamed:@"1a.png"],
                                [UIImage imageNamed:@"1b.png"],
                                nil];

 // all frames will execute in 25 seconds
 ImageView.animationDuration = 25;
// start animating
[ImageView startAnimating];
ImageView.layer.borderWidth = 2;
ImageView.layer.borderColor = [[UIColor whiteColor]CGColor];
[ImageView.layer setMasksToBounds:YES];
[ImageView.layer setCornerRadius:15.0f];
[baseView addSubview:ImageView]; 

现在,如果有人可以指导我如何暂停UIImage animation这个NSTimer暂停时的幻灯片.

感谢帮助.

Answer 1

您可以使用apple提供的代码暂停和恢复动画.

-(void)pauseLayer:(CALayer*)layer
{
CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
layer.speed = 0.0;
layer.timeOffset = pausedTime;
}

-(void)resumeLayer:(CALayer*)layer
{
CFTimeInterval pausedTime = [layer timeOffset];
layer.speed = 1.0;
layer.timeOffset = 0.0;
layer.beginTime = 0.0;
CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
layer.beginTime = timeSincePause;
}

要使CALayer传递给pauseLayer函数,您可以使用以下代码.

CALayer *player = ImageView.layer;
[self pauseLayer:player];

希望它能帮到你.