ios - 如何暂停 UIView 动画

Question

在 iOS5.0 中使用块，假设我们有一个 UIViewAnimationOptionAutoreverse 动画，并且需要在反向动画开始之前放置一个延迟.. 我们该怎么做呢？

感谢您对此的帮助

Answer 1

The best way to pause and resume animation :

add QuartzCore framework 


then use the following apple's code 

-(void) pause
{

CFTimeInterval pausedTime = [m_pCustomImageBtnObj.layer convertTime:CACurrentMediaTime() fromLayer:nil];

    obj.layer.speed = 0.0;

    obj.layer.timeOffset = pausedTime;
}


-(void) resume
{

CFTimeInterval pausedTime = [obj.layer timeOffset];

    obj.layer.speed = 1.0;

    obj.layer.timeOffset = 0.0;

    obj.layer.beginTime = 0.0;

    CFTimeInterval timeSincePause = [obj.layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;

    obj.layer.beginTime = timeSincePause;


}

Answer 2

不确定这是否正是您想要做的，但这是我用来将视图移动到屏幕上，暂停 1 秒钟，然后将视图移出屏幕的方法。

[UIView animateWithDuration:0.5 animations:^{
    self.view.frame = viewFrameOnScreen;
    self.view.alpha = 1.0;
} completion:^(BOOL finished){
    [UIView animateWithDuration:0.5 delay:1 options:0 animations:^{
        self.view.frame = viewFrameOffScreen;
        self.view.alpha = 0.0f;

    } completion:^(BOOL finished){}];
}];

Answer 3

您可以尝试这样的动画完成块：

[UIView animateWithDuration:0.6 animations:^(void)
 {
     self.label.bounds = CGRectMake(10, 10, 200, 200); 

 }completion:^(BOOL finished) {
     [UIView animateWithDuration:0.6 animations:^(void)
      {
          self.label.bounds = CGRectMake(10, 10, 100, 100); 

      }completion:^(BOOL finished) {

      }];

 }];

Answer 4

您应该为此使用关键帧动画。下面是一段代码来做反转旋转：

self.animations = [NSDictionary dictionaryWithObjects:
                   [NSArray arrayWithObjects:
                    [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"],
                    [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"]                         

                    , nil ]
                                              forKeys:
                   [NSArray arrayWithObjects: THERE_ANIM_KEY, BACK_AGAIN_ANIM_KEY , nil ]];
CAKeyframeAnimation *kfAnim = [animations objectForKey: THERE_ANIM_KEY];
kfAnim.duration = 2;
kfAnim.repeatCount = 1;
kfAnim.values = [NSArray arrayWithObjects: 
                 [NSNumber numberWithFloat: 0.0 * M_PI],
                 [NSNumber numberWithFloat: 1.0 * M_PI],
                 [NSNumber numberWithFloat: 2.0 * M_PI],
                 [NSNumber numberWithFloat: 2.0 * M_PI], //here is delay
                 [NSNumber numberWithFloat: 1.0 * M_PI],
                 [NSNumber numberWithFloat: 0.0 * M_PI],
                 nil];
 kfAnim.keyTimes = [NSArray arrayWithObjects: 
 [NSNumber numberWithFloat: 0.0 ],
 [NSNumber numberWithFloat: 0.3 ],     
 [NSNumber numberWithFloat: 0.5 ],  //time of delaying in proportion of general animation duration   
 [NSNumber numberWithFloat: 0.5 ],
 [NSNumber numberWithFloat: 0.8 ],
 [NSNumber numberWithFloat: 1.0 ], nil];

您也可以使用记住初始状态并重新设置动画

• (void)animationDidStop:(CAAnimation *)动画完成:(BOOL)标志

使用 performSelector:withObject:afterDelay: 的动画委托方法。这更简单且易于设置延迟。

Answer 5

RIAZ 在 Swift 3 中的回答：

func pauseAnimation() {
    let pausedTime = obj.layer.convertTime(CACurrentMediaTime(), from: nil)
    obj.layer.speed = 0.0
    obj.layer.timeOffset = pausedTime
}

func resumeAnimation() {
    let pausedTime = obj.layer.timeOffset
    obj.layer.speed = 1.0
    obj.layer.timeOffset = 0.0
    obj.layer.beginTime = 0.0
    let timeSincePause = obj.layer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime
    obj.layer.beginTime = timeSincePause
}