无法通过编程同时满足约束。迅捷的iOS

Unable to simultaneously satisfy constraints programmatically. Swift iOS

我试图按一下按钮来更改约束。

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@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()
}

两个约束都激活后，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：

每个人在这里都有正确的答案，这对我有很大帮助。我刚刚接受了带有示例代码的代码。

谢谢大家！

相关讨论

这里的问题是创建约束的方式。每次在代码中引用约束时，您都不会引用位于对象上的实际约束，而是创建新的约束，最终导致冲突。解决方案是在每种情况下在View Controller中创建NSLayoutConstraint对象，然后修改NSLayoutConstraint .constant值。最后，不要忘记在视图控制器上调用" layoutIfNeeded()"函数。

每次点击都会引起新的冲突

1	var botCon:NSLayoutConstraint!

1 2	botCon = someTableView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -16) botCon.isActive = true

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

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