ios - 嵌套参数化闭包参数异常

Question

我正在尝试使用 UIView.animateWithDuration 执行一组嵌套动画，但是无论我使用的闭包返回参数如何，我似乎都会遇到异常。

Cannot invoke 'animateWithDuration' with an argument list of type '(NSTimeInterval, delay: NSTimeInterval, options: UIViewAnimationOptions, animations: () -> Void, completion: (Bool) -> Void)'

这是有问题的函数

func animateLikeButton(button: UIButton?)
{
    button?.userInteractionEnabled = false;

    let pixelsToScale = 9.0;
    let pixelsToShrink = 4.0;

    let buttonFrame = button?.frame

    // Big
    let scaleOriginX = Double(buttonFrame!.minX) - pixelsToScale / 2.0
    let scaleOriginY = Double(buttonFrame!.minY) - pixelsToScale / 2.0
    let scaleSizeX = Double(buttonFrame!.width) + pixelsToScale
    let scaleSizeY = Double(buttonFrame!.height) + pixelsToScale

    // Small
    let shrinkOriginX = Double(buttonFrame!.minX) + pixelsToScale / 2.0
    let shrinkOriginY = Double(buttonFrame!.minY) + pixelsToScale / 2.0
    let shrinkSizeX = Double(buttonFrame!.width) - pixelsToScale
    let shrinkSizeY = Double(buttonFrame!.height) - pixelsToScale

    UIView.animateWithDuration(NSTimeInterval(0.4), delay:NSTimeInterval(0), options: UIViewAnimationOptions.CurveEaseInOut,
        animations:
        {
            () -> Void in
            button?.frame = CGRect(origin: CGPoint(x: scaleOriginX, y: scaleOriginY), size: CGSize(width: scaleSizeX, height: scaleSizeY))
        },
        completion:
        {
            (finished: Bool) -> Void in
            UIView.animateWithDuration(NSTimeInterval(0.2), delay:NSTimeInterval(0.1), options: UIViewAnimationOptions.CurveEaseInOut,
                animations:
                {
                    () -> Void in
                    button?.frame = CGRect(origin: CGPoint(x: shrinkOriginX, y: shrinkOriginY), size: CGSize(width: shrinkSizeX, height: shrinkSizeY))
                },
                completion:
                {
                    (finished: Bool) -> Void in
                    UIView.animateWithDuration(NSTimeInterval(0.2), delay:NSTimeInterval(0), options: UIViewAnimationOptions.CurveEaseInOut,
                        animations:
                        {
                            () -> Void in
                            button?.frame = buttonFrame!
                        },
                        completion:
                        {
                            (finished: Bool) -> Void in
                            button?.userInteractionEnabled = true
                        }
                    )
                }
            )
        }
    )
}

老实说，我一定已经尝试了闭包返回参数的所有可能组合(有和没有可选参数)，但没有成功。例如:

(_) -> Void in
(finished: Bool) in
(finished: Bool) -> bool in
finished in
_ in

有什么建议可以尝试吗？

Answer 1

添加显式 return 应该可以解决问题。下面的代码显示了一个例子:

UIView.animateWithDuration(1.0, delay: 1.0, options: nil, animations:
{
    self.imgIcon?.alpha = 0.0
    return
},
completion:
{
    finished in
    self.imgIcon?.hidden = true
    return
})