ios - 无法以编程方式同时满足约束条件。 swift iOS

Question

我正尝试按一下按钮更改约束。

@IBAction func firstButton(_ sender: Any) {
    someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -16).isActive = false
    someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -46).isActive = true
    someTableView.updateConstraints()
}

@IBAction func secondButton(_ sender: Any) {
    someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -46).isActive = false
    someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -16).isActive = true
    someTableView.updateConstraints()
}

一旦两个约束都处于事件状态，我就会出错。他们不会停用:

[LayoutConstraints] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it.

[shortened].bottom == [shortened].bottom - 46 (active)>

[shortened].bottom == [shortened].bottom - 16 (active)>

Will attempt to recover by breaking constraint

[shortened].bottom == [shortened].bottom - 16 (active)>

编辑:

这里每个人都有正确答案，对我帮助很大。我刚刚接受了带有示例代码的那个。

谢谢大家!

Answer 1

每次点击都会引起新的冲突

var botCon:NSLayoutConstraint!

//

 botCon = someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -16)
 botCon.isActive = true

//

@IBAction func firstButton(_ sender: Any) {
    botCon.constant = -46
    self.view.layoutIfNeeded()
}

@IBAction func secondButton(_ sender: Any) {
    botCon.constant = -16
    self.view.layoutIfNeeded()
}