我使用这段代码:
func show(){
view.translatesAutoresizingMaskIntoConstraints = false
view.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
view.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
view.heightAnchor.constraint(equalToConstant: view.frame.height - 300).isActive = true
view.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
}
func hide(){
view.translatesAutoresizingMaskIntoConstraints = false
view.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
view.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
view.heightAnchor.constraint(equalToConstant: view.frame.height + 300).isActive = true
view.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
}
show
功能正常,但 hide
功能不起作用,heightAnchor
不起作用。
最佳答案
先声明约束
var heightArchonWhenShow = view.heightAnchor.constraint(equalToConstant: view.frame.height - 300)
var heightArchonWhenHide = view.heightAnchor.constraint(equalToConstant: view.frame.height + 300)
在初始化您对 ViewDidLoad 的约束后
func setConstraints(){
view.translatesAutoresizingMaskIntoConstraints = false
view.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
view.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
view.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
heightArchonWhenShow.isActive = true
}
并且简单激活它们,不要覆盖。像这样:
func show(){
heightArchonWhenShow.isActive = true
heightArchonWhenHide.isActive = false
}
func hide(){
heightArchonWhenShow.isActive = false
heightArchonWhenHide.isActive = true
}
如果你想你也可以动画变化,就像那样:
func hide(){
heightArchonWhenShow.isActive = false
heightArchonWhenHide.isActive = true
UIView.animate(withDuration: 0.3) {
self.view.layoutIfNeeded()
}
}
关于swift - heightAnchor.constraint 不改变 View 高度,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53739783/