UIView的高度约束动画

Posted 2023-03-13

【中文标题】UIView的高度约束动画

【英文标题】：Height constraint animation of UIView

【发布时间】：2018-01-25 19:59:59

【问题描述】：

我有名为 DetailView 的 UIView 具有以下约束：

DetailView.top = top
DetailView.trailing = Safe Area.trailing
DetailView.leading = Safe Area.leading
height = 295

全部在 StoryBoard 中制作。 DetailView is this gray rectangle on an image

我想在点击按钮后改变这个 UIView 的高度，所以我有 IBAction 来实现这个

@IBAction func detailViewTapped(_ sender: Any) 
        if detailViewHeightConstraint.constant < 500 
            detailViewHeightConstraint.constant = 523
            UIView.animate(withDuration: 0.5) 
                self.detailView.layoutIfNeeded()
            
            arrowImageView.image = UIImage(named: "up-arrow")
         else 
            detailViewHeightConstraint.constant = 295
            UIView.animate(withDuration: 0.5) 
                self.detailView.layoutIfNeeded()
            
            arrowImageView.image = UIImage(named: "down-arrow")
        
    

改变尺寸效果很好，但动画效果不行。我想实现扩展到底部的效果，但是动画在屏幕之间开始一些东西，并且正在扩展到底部和顶部。 Start of animation can be seen on this picture怎样才能达到理想的效果？

【参考方案1】：

动画主视图

 @IBAction func detailViewTapped(_ sender: Any) 
    if detailViewHeightConstraint.constant < 500 
        detailViewHeightConstraint.constant = 523
        UIView.animate(withDuration: 0.5) 
            self.view.layoutIfNeeded()
        
        arrowImageView.image = UIImage(named: "up-arrow")
     else 
        detailViewHeightConstraint.constant = 295
        UIView.animate(withDuration: 0.5) 
            self.view.layoutIfNeeded()
        
        arrowImageView.image = UIImage(named: "down-arrow")