ios - 动画不适用于 UIImageView

Question

我添加了一个 UIImageView 作为 subview 。我正在尝试使用变换对其进行动画处理。动画没有，但是 ImageView 已正确缩放，只是没有自动反转。我做错了什么吗？

UIImageView * iv_tap = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"gesture_tap"]];
    iv_tap.center = point;
    iv_tap.tag = 779;
    iv_tap.hidden = true;
    [UIView animateWithDuration:2.0
                          delay:.05
                        options: UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveLinear
                     animations:^{
                         iv_tap.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.8, 1.8);
                     }
                     completion:NULL];


    [self addSubview:iv_tap];

Answer 1

将 imageView 添加到 view 后，您需要制作动画。如果您在 addSubView 之前执行动画， ImageView 不在 View 层次结构中，您看不到任何动画。

 UIImageView * iv_tap = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"gesture_tap"]];
[self.view addSubview:iv_tap];   //this could be self in your case
iv_tap.tag = 779; 

[UIView animateWithDuration:2.0 delay:0.05  options:UIViewAnimationOptionCurveEaseOut animations:^{

    iv_tap.center=self.view.center;
    iv_tap.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.8, 1.8);

    [self.view layoutIfNeeded];    //this could be self in your case

} completion:^(BOOL finished) {
        //do your stuff when animation is done
}];

如果您正在子类化 UIView，那么您甚至可以将它放在 drawRect 方法中:

UIImageView * iv_tap = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"gesture_tap"]];
[self addSubview:iv_tap];   
iv_tap.tag = 779;

[UIView animateWithDuration:2.0 delay:0.05  options:UIViewAnimationOptionCurveEaseOut animations:^{

    iv_tap.center=self.center;
    iv_tap.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.8, 1.8);

    [self layoutIfNeeded];   

} completion:^(BOOL finished) {
        //do your stuff when animation is done
 }];