动画后计算uiview的高度 [英] Calcul height of uiview after animating this one

问题描述

我有一个修改 UIView 约束的动画，我需要在动画之后知道这个 UIView 的大小，但在动画开始之前...

I have an animation who modify the constraint of an UIView and i need to know the size of this UIView after animate this, but before the animation begin...

故事板

当用户滚动 UITableView 时，我更新了黑色 UIView 的 heightConstraint，我需要更新 UIView 后的高度，因为我需要在函数 viewDidLayoutSubviews 中固定黄色 UIview 的高度.

When the user scroll the UITableView I update the heightConstraint of the black UIView, I need the height after update the UIView because i need in the function viewDidLayoutSubviews to fixe the height of the Yellow UIview.

这是我用于动画 UIView 的代码:

this is the code I use for animate the UIView:

self.headerIsCollapsed = true
self.heightProfilView.constant -= (self.view.bounds.height / 5)
UIView.animate(withDuration: 0.3, animations: {
   self.view.layoutIfNeeded()
   self.imageUserProfil.layer.opacity = 0
})

我需要这里的值:

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    heightTopBar.constant = // here i need the height of the UIView after animating this
}

所以，问题是:我如何在设置动画后预先计算 UIView 的高度?

So, the question is: How I can pre-calculate the height of the UIView after animating this ?

推荐答案

试试这个:

self.headerIsCollapsed = true
//create this property at instance level in your viewcontroller class
self.heightBeforeAnimation = self.heightProfileView.frame.size.height
self.heightProfilView.constant -= (self.view.bounds.height / 5)
UIView.animate(withDuration: 0.3, animations: {
  self.view.layoutIfNeeded()
  self.imageUserProfil.layer.opacity = 0
}){ (isCompleted) in
    //create this property at instance level in your viewcontroller class
   self.heightAfterAnimation = self.heightProfileView.frame.size.height
}

并调用任何函数并使用包含动画视图前后高度值的两个变量的值.

and call whatever function and use the value of two variables containing value of height before and after animating your view.

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