第一種方法:，使用監聽

 

UIView beginAnimations

方法如下：

 

 

    [UIView beginAnimations:nil context:nil];
    //代理，監聽對象
    [UIView setAnimationDelegate:self];

    //removeCover 是動畫執行完後要調用方法
    [UIView setAnimationDidStopSelector:@selector(removeCover)];
    self.coverBtn.alpha =0.0;
    [UIView commitAnimations];

removeCover:

 

 

-(void)removeCover
{
    [self.coverBtn removeFromSuperview];
    self.coverBtn=nil;
}

第二種方法：使用block, UIView animateWithDuration

 

 

    [UIView animateWithDuration:1.0 animations:^{
        self.coverBtn.alpha= 0.0;
        self.iconbtn.frame = self.oldPicFrame;
        
    } completion:^(BOOL finished) {
        [self.coverBtn removeFromSuperview];
        self.coverBtn =nil;
    }];