Swift以编程方式设置视图约束错误日志

Question

我有UIViewController和几个视图，其中一个是包含广告视图(AdMob(的UIView。

这就是我设置视图Constraint:的方式

selectBtn.anchor(top: view.safeAreaLayoutGuide.topAnchor, leading: nil, bottom: nil, trailing: nil, padding: .init(top: 50.0, left: 10.0, bottom: 0, right: 10.0))
selectBtn.centerXToSuperview()

statusLabel.anchor(top: selectBtn.bottomAnchor, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: nil, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 20.0, left: 10.0, bottom: 0, right: 10.0))
fileSizeLabel.anchor(top: statusLabel.bottomAnchor, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: nil, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 10.0, left: 10.0, bottom: 0, right: 10.0))
adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: -50.0, right: 0.0), size: .init(width: view.width, height: 50.0))
imageView.anchor(top: fileSizeLabel.bottomAnchor, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: adView.topAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 10.0, left: 10.0, bottom: 10.0, right: 10.0))

adView是全尺寸的，但由于我添加了填充，所以在视图下方(我只想在广告可用时显示adview(。

当广告可用时，我调用此代码(使adview可见(：

adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0), size: .init(width: view.width, height: 50.0))

问题是我得到了这个错误：

[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. 
(
"<NSLayoutConstraint:0x600001c34af0 UIView:0x7fbdf040e130.bottom == UILayoutGuide:0x60000061ae60'UIViewSafeAreaLayoutGuide'.bottom + 50   (active)>",
"<NSLayoutConstraint:0x600001c3c2d0 UIView:0x7fbdf040e130.bottom == UILayoutGuide:0x60000061ae60'UIViewSafeAreaLayoutGuide'.bottom   (active)>"
)
Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x600001c34af0 UIView:0x7fbdf040e130.bottom == UILayoutGuide:0x60000061ae60'UIViewSafeAreaLayoutGuide'.bottom + 50   (active)>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.

这是我正在使用的锚定方法：

open func anchor(top: NSLayoutYAxisAnchor?, leading: NSLayoutXAxisAnchor?, bottom: NSLayoutYAxisAnchor?, trailing: NSLayoutXAxisAnchor?, padding: UIEdgeInsets = .zero, size: CGSize = .zero) -> AnchoredConstraints {

translatesAutoresizingMaskIntoConstraints = false
var anchoredConstraints = AnchoredConstraints()

if let top = top {
anchoredConstraints.top = topAnchor.constraint(equalTo: top, constant: padding.top)
}

if let leading = leading {
anchoredConstraints.leading = leadingAnchor.constraint(equalTo: leading, constant: padding.left)
}

if let bottom = bottom {
anchoredConstraints.bottom = bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom)
}

if let trailing = trailing {
anchoredConstraints.trailing = trailingAnchor.constraint(equalTo: trailing, constant: -padding.right)
}

if size.width != 0 {
anchoredConstraints.width = widthAnchor.constraint(equalToConstant: size.width)
}

if size.height != 0 {
anchoredConstraints.height = heightAnchor.constraint(equalToConstant: size.height)
}

[anchoredConstraints.top, anchoredConstraints.leading, anchoredConstraints.bottom, anchoredConstraints.trailing, anchoredConstraints.width, anchoredConstraints.height].forEach{ $0?.isActive = true }

return anchoredConstraints
}

知道问题出在哪里吗？

Answer 1

当广告可用时，您应该在此处使用创建的底部约束

adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: -50.0, right: 0.0), size: .init(width: view.width, height: 50.0))

但当你在这里创建另一个底部约束时，

adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0), size: .init(width: view.width, height: 50.0))

它与旧的1冲突，所以你应该有一个实例可用的

var bottomCon:NSLayoutConstraint!

并在此处为底部锚最初提供零

adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom:nil, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: -50.0, right: 0.0), size: .init(width: view.width, height: 50.0))

加上像这个

bottomCon = adView.bottomAnchor.constraint(equalTo:view.safeAreaLayoutGuide.bottomAnchor,constant:50)
bottomCon.isActive = true

在这之后，当你需要显示广告播放与恒定有效性

bottomCon.constant = 0
self.view.layoutIfNeeded()

Answer 2

您为adView提供了冲突约束。

adView.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor, padding: .init(top: 0.0, left: 0.0, bottom: -50.0, right: 0.0), size: .init(width: view.width, height: 50.0))

提供底部结构和衬垫。删除其中一个，它会很好。