以编程方式快速更改Xib高度

Question

我实现了2个Xib文件到View Controller（1个View，1个CollectionView）。我想在滚动时显示/隐藏视图。我可以隐藏视图（设置高度：0），但是当我想返回（设置高度：50）时，它不起作用。

谢谢。

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

    if scrollView.panGestureRecognizer.translation(in: scrollView).y < 0{

        self.searchFieldView.heightAnchor.constraint(equalToConstant: 0).isActive = true
        self.searchFieldView.clipsToBounds = true
        //self.view.setNeedsLayout()
        self.view.layoutIfNeeded()
    }
    else{

        self.searchFieldView.heightAnchor.constraint(equalToConstant: 50).isActive = true
        //self.view.setNeedsLayout()
        self.view.layoutIfNeeded()
    }

}

Answer 1

从xib获取searchFieldView的高度，并根据条件更改其常数值。

@IBOutlet weak var vwHeightConstraint: NSLayoutConstraint!

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

    if scrollView.panGestureRecognizer.translation(in: scrollView).y < 0{

        vwHeightConstraint.constant = 0

        self.searchFieldView.clipsToBounds = true
        //self.view.setNeedsLayout()
        self.view.layoutIfNeeded()
    }else{
         vwHeightConstraint.constant = 50

        //self.view.setNeedsLayout()
        self.view.layoutIfNeeded()
    }

}

希望它能正常工作。尝试一下