Not all content is animated inside a stack view when hiding it

Question

I'm currently working on a iOS (swift 3) app. I have a simple vertical stack view containing 2 horizontal stack views. In some cases I want to hide the bottom one. I do so by using the following code

 UIView.animate(withDuration: 3) {
                self.bottomStackView.isHidden = true;
 };

The animation shown below doesn't really do what I would expect:

While the border of the buttons is animated properly when hiding, the text inside each button doesn't seem to be affected until the very end. Any idea as to how I could fix this?

Answer 1

我不确定这一点，我认为堆栈视图有时会导致奇怪的行为。您是否尝试在UIView.animate块中添加“self.view.layoutIfNeeded（）”？像这样：

UIView.animate(withDuration: 3) {
      self.bottomStackView.isHidden = true
      self.view.layoutIfNeeded()
}

我认为如果你将“self.bottomStackView.isHidden = true”置于UIView.animate之上，它也应该有效，但不确定，不是它的专家。 另外，我认为你不需要使用“;”在你的swift代码行之后：）

Answer 2

我一直在研究这个主题，似乎大多数articles都建议使用堆栈来执行动画会很好。但是我也发现动画只适用于animatable properties， isHidden 不是其中之一。

在经过一些试验和错误后，我发现 isHidden 可以使用堆栈视图进行动画制作，但是你可能会发现孩子行为不端。到目前为止，我发现的唯一解决方法是这样：

        let duration = 0.5;
        let delay = 0;
        UIView.animate(withDuration: duration, delay: delay, animations: {
            self.bottomStack.isHidden = self.hideBottomStack;
        })
        UIView.animate(withDuration: duration/2, delay: delay, animations: {
            self.bottomStack.alpha = 0;
        })

你在这里注意到我基本上＆＃34;转向＃34; alpha属性在我隐藏堆栈的一半时间内降至0。这样可以在文本与上层堆栈重叠之前隐藏文本。还要注意我也可以决定做这样的事情：

       UIView.animate(withDuration: duration, delay: delay, animations: {
           self.bottomStack.alpha = 0;
       }, completion: { (_) in 
           self.bottomStack.isHidden = true;
       })

这也会隐藏底部堆栈，但是你会失去隐藏动作以支持淡入淡出的动作，并在淡入淡出完成后隐藏堆栈。