ios - 当设备旋转改变时创建附加约束

Question

我有一个 subview ，它的约束通过 IBOutlet 引用了 super View ，我正在通过停用它来更改约束，然后赋予新值并再次激活，这工作正常并且没有警告但是当设备旋转和似乎添加了另一个约束(我在 Storyboard 中添加的约束) 代码:

bottomViewBottomConstraint.isActive = false
if self.isHide {
    bottomViewBottomConstraint = bottomView.bottomAnchor.constraint(equalTo: playerView.bottomAnchor,constant:0)
}
else {
    bottomViewBottomConstraint = bottomView.bottomAnchor.constraint(equalTo: playerView.bottomAnchor,constant:bottomView.frame.height + 50)
}
bottomViewBottomConstraint.isActive = true

旋转后警告:

"<NSLayoutConstraint:0x600003fdce60 UIView:0x7fc034f050b0.bottom == PlayKit.PlayerView:0x7fc034f69870.bottom + 143.333   (active)>",
"<NSLayoutConstraint:0x600003fe3480 'bottomViewId' V:[UIView:0x7fc034f050b0]-(0)-|   (active, names: 
'|':PlayKit.PlayerView:0x7fc034f69870 )>"

底 View Storyboard约束

Answer 1

你在viewDidLoad 中需要它

var bottomViewBottomConstraint:NSLayoutConstraint!

---

bottomViewBottomConstraint = bottomView.bottomAnchor.constraint(equalTo: playerView.bottomAnchor,constant:0)

---

和常量一起玩

bottomViewBottomConstraint.constant = self.isHide ? 0 :   bottomView.frame.height + 50
self.view.layoutIfNeeded()