ios - Swift 动画问题

Question

我正在创建一个非常基本的 Swift 函数，它将 UIView 设置为动画到屏幕中央，使其出现并放大一倍，然后在返回到其原始位置时最后缩小回其原始大小。这是代码:

func toTheCorner(view: UIView, delay: Double)
{
    // record original position
    let originalCenter = view.center
    // record original bounds
    let b = view.bounds

    UIView.animateWithDuration(0.1, delay: delay, usingSpringWithDamping: 0.2, initialSpringVelocity: 0, options: .CurveEaseOut, animations: {

        // move view to center of screen
        view.center.x = self.view.bounds.width/2
        view.center.y = self.view.bounds.height/2


        }, completion: nil)

    UIView.animateWithDuration(0.9, delay: delay + 0.1, usingSpringWithDamping: 0.8, initialSpringVelocity: 10, options: .CurveEaseOut, animations: {

        // Fade image in
        view.alpha = 1.0

        // Increase size
        view.bounds.size.height = b.height + b.height/2
        view.bounds.size.width = b.width + b.width/2

        }, completion: nil)

    UIView.animateWithDuration(0.7, delay: delay + 1.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 10, options: .CurveEaseOut, animations: {

        // Shrink to original size
        view.bounds.size.height = b.height
        view.bounds.size.width = b.width

        // Move to original position
        view.center = originalCenter


    }, completion: nil)

}

产生问题的行是:

view.center = originalCenter

如果没有这一行，函数将按预期执行。 View 出现在屏幕中央，然后加倍然后缩小。但是，只要我输入“view.center = originalCenter”， View 就会出现在屏幕中心的原始点正对面而不是中间，然后移动到它的原始点。

这条线如何影响前两个动画？这看起来应该可行，而且非常简单......

谢谢!本

Answer 1

你应该为此使用完成 block ；

func toTheCorner(view: UIView, delay: Double)
{
    // record original position
    let originalCenter = view.center
    // record original bounds
    let b = view.bounds

    UIView.animateWithDuration(0.1, delay: delay, usingSpringWithDamping: 0.2, initialSpringVelocity: 0, options: .CurveEaseOut, animations: {

        // move view to center of screen
        view.center.x = self.view.bounds.width/2
        view.center.y = self.view.bounds.height/2

        }, completion: { finished in 
   UIView.animateWithDuration(0.9, delay: delay + 0.1, usingSpringWithDamping: 0.8, initialSpringVelocity: 10, options: .CurveEaseOut, animations: {

        // Fade image in
        view.alpha = 1.0

        // Increase size
        view.bounds.size.height = b.height + b.height/2
        view.bounds.size.width = b.width + b.width/2

        }, completion: { finished in 
    UIView.animateWithDuration(0.7, delay: delay + 1.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 10, options: .CurveEaseOut, animations: {

        // Shrink to original size
        view.bounds.size.height = b.height
        view.bounds.size.width = b.width

        // Move to original position
        view.center = originalCenter
    }, completion: nil)})
    })
}