iOS - UIView setCenter在UIView animateWithDuration中不起作用

我有一个让我疯狂的问题,我想我没有足够的知识来找到这个问题的答案.

这里有一个完美的代码:

NSLog(@"%f, %f", imageList.center.x, imageList.center.y);
[imageList setCenter:CGPointMake(imageList.center.x, -imageList.center.y)];
NSLog(@"=> %f, %f", imageList.center.x, imageList.center.y);

给我以下输出:

2016-01-08 11:48:42.585 User[4047:600095] 160.000000, 284.000000
2016-01-08 11:48:42.585 User[4047:600095] => 160.000000, -284.000000

现在,如果我把这个setCenter放到UIView animationWithDuration中,就像这样

NSLog(@"%f, %f", imageList.center.x, imageList.center.y);
[UIView animateWithDuration:0.3 animations:^{
   [imageList setCenter:CGPointMake(imageList.center.x, -imageList.center.y)];  
} completion:^(BOOL finished) {*/
    NSLog(@"=> %f, %f", imageList.center.x, imageList.center.y);
}];

我得到这个输出:

2016-01-08 11:48:42.585 User[4047:600095] 160.000000, 284.000000
2016-01-08 11:48:42.585 User[4047:600095] => 160.000000, 284.000000

你们有什么想法吗？我检查了约束和autoLayout,一切都很好.

试试这个 :

Objective-C的

[UIView animateWithDuration:0.3 delay:0.0 options:(UIViewAnimationOptionCurveLinear | UIViewAnimationOptionAllowUserInteraction) animations:^{
    [imageList setCenter:CGPointMake(imageList.center.x, -imageList.center.y)];
} completion:nil];

斯威夫特4

UIView.animate(withDuration: 0.3, delay: 0.0, options: .curveLinear, animations: {
    imageList.center = CGPoint(x: imageList.center.x, y: -imageList.center.y)
}, completion: nil)