在 animateWithDuration:completion 的完成块中删除 UIView

Question

我正在使用 animateWithDuration:completion 为 UIView 的某些属性设置动画。在这些动画完成后，我想从他的超级视图中删除这个视图。 问题是，如果我在完成块 removeFromSuperView 内添加，我根本不会得到动画。我找到的解决方法是删除 dispatch_after 中的视图。为什么？

     var loadingView: Loading!  //This is a UIView loaded from a Nib
    let delaySecs: NSTimeInterval = 2
    UIView.animateWithDuration(delaySecs, animations: { () -> Void in
        self.loadingView.cherrysImageView.transform = CGAffineTransformMakeScale(2, 2)
        self.loadingView.cherrysImageView.alpha = 0
    }) { (succeed) -> Void in
        //Can't remove the view here, otherwise i get NO animation
        //self.loadingView.removeFromSuperview()
    }

        //And if i add this instead of removing the view in the completion block, it works as expected
    let delay = delaySecs * Double(NSEC_PER_SEC)
    let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
    dispatch_after(time, dispatch_get_main_queue()) { () -> Void in
        self.loadingView.removeFromSuperview()
    }

Answer 1

动画完成块在动画过程中被多次调用，但只有在成功为真时才能删除所有内容。

var loadingView: Loading!  //This is a UIView loaded from a Nib
let delaySecs: NSTimeInterval = 2
UIView.animateWithDuration(delaySecs, animations: { () -> Void in
    self.loadingView.cherrysImageView.transform = CGAffineTransformMakeScale(2, 2)
    self.loadingView.cherrysImageView.alpha = 0
}) { (succeed) -> Void in
    if succeed {
        self.loadingView.removeFromSuperview()
    }
}