设备旋转更改时会创建其他约束

Question

我有一个子视图，其约束通过IBOutlet引用超级视图，我通过停用它然后给出新值并再次激活来改变约束，这工作正常，没有警告，但问题发生在设备旋转时，它似乎另一个约束被添加（我在故事板中添加的约束）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

轮换后警告：

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

底视图故事板约束

Answer 1

你需要在viewDidLoad它

var bottomViewBottomConstraint:NSLayoutConstraint!

---

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

---

并且不断地玩耍

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