使用块的多级动画

Question

我知道你可以使用像这样的块执行两阶段动画:

[UIView animateWithDuration:25.0 delay:0.0 options:UIViewAnimationCurveLinear animations:
     ^{ 
         aView.alpha = 2.5;         
     } 
         completion:^(BOOL finished)
     {
         aView.hidden = YES; 
     }
 ];

..但是如何使用块创建多级(超过2个)动画？

Answer 1

使用嵌套动画:

[UIView animateWithDuration:0.5 
                      delay:0.0 
                    options:UIViewAnimationOptionBeginFromCurrentState 
                 animations:^{
                     //first animation
                 }
                 completion:^(BOOL finished){[UIView animateWithDuration:0.5 
                                                                   delay:0.0 
                                                                 options:UIViewAnimationOptionBeginFromCurrentState 
                                                              animations:^{
                                                                  //second animation
                                                              }
                                                              completion:^(BOOL finished){//and so on..
                                                              }];}];

Answer 2

或者你可以制作一个递归的多阶段动画方法:

-(void) multiStageAnimate{
[UIView animateWithDuration:0.5 
                      delay:0.0 
                    options:UIViewAnimationOptionBeginFromCurrentState 
                 animations:^{
                     //animation code
                 }
                 completion:^(BOOL finished){
                     if(/* If terminating condition not met*/)
                         [self multiStageAnimate];
                 }];
}