获取UIView高度并将其用于自身的约束 [英] Get UIView height and use it for its own constraints

问题描述

在我的 UIView 实际显示之前，我怎么能将它的高度呈现出来？

How can I can the height of my UIView before it is actually presented?

这是我尝试过的：

print(wishWishView.frame.size.height)

self.view.addSubview(self.wishWishView)

wishWishView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
wishWishView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true

wishWishConstraint =  wishWishView.topAnchor.constraint(equalTo: self.view.bottomAnchor)
wishWishConstraint.isActive = true

UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1.0, initialSpringVelocity: 1.0, options: .curveEaseInOut, animations: {
        self.transparentView.alpha = 0.7
        self.wishWishConstraint = self.wishWishView.topAnchor.constraint(equalTo: self.view.bottomAnchor, constant: - self.keyboardHeight)
        self.view.layoutIfNeeded()

    }, completion: nil)

问题是 wishWishView.frame.size.height 为 0 直到实际显示该视图。

The problem is that wishWishView.frame.size.height is 0 until the view is actually presented.

我实际上想要实现的目标是将视图隐藏在底部。我知道我可以只使用 constant：1000 ，但这是蛮力的，不是很干净。

What I actually want to achieve is to hide the view at the bottom. I know I could just use constant: 1000 but that's quite brute force and not very clean.

编辑：

过程：

1。。用户点击按钮

2。视图从滑水板的右下方显示。

2. view appears from the bottom to right above the kayboard

3。用户关闭视图

4。视图从视图底部移至底部

4. view moves to the bottom out of the view

动画

我拥有所有函数和变量（ func viewAppears ， keyboardHeight ，...），但我正在为约束苦苦挣扎。

I have all the functions and variables (func viewAppears, keyboardHeight,...), but I am struggling with the constraints.

推荐答案

所以我解决了我的问题，动画现在按预期工作。但是，实际问题仍未解决。

So I solved my problem and the animation is now working as expected. However the actual problem is still unsolved.

let height = CGFloat(130)

@objc func addWishButtonTapped(){    

    let screenSize = UIScreen.main.bounds.size
    self.wishWishView.frame = CGRect(x: 0, y: screenSize.height, width: screenSize.width, height: height)
    self.view.addSubview(self.wishWishView)

    UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1.0, initialSpringVelocity: 1.0, options: .curveEaseInOut, animations: {
    self.transparentView.alpha = 0.7
    self.wishWishView.frame = CGRect(x: 0, y: screenSize.height - self.height - self.keyboardHeight, width: screenSize.width, height: self.height)

}, completion: nil)

您可以看到我正在使用硬编码的高度 ...

As you can see I am using the hard-coded height...

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