UIView的高度约束打破子视图的高度约束

  • Z时代
  • 2024-01-10
  • 分类：问答

我有一个非常简单的设置，我无法做到我想要的。我正在尝试添加inputAccessoryView。UIView的高度约束打破子视图的高度约束

对于inputAccessoryView我有一个UIView（ViewA）配有一个子视图（ViewB）。 ViewB固定为ViewA的所有边缘。 查看B有固定的高度，需要高度为ViewA和ViewB。

ViewA的不是由我设定，但是0打破ViewB（设定为42）的高度。

ViewA被添加作为在UIViewController的视图一个子视图并固定在底部和两个前缘和后缘（ViewA和ViewB的所以宽度应是UIViewController的视图，其中它是）。

这里是我的代码：

override init(frame: CGRect) { 
    super.init(frame: frame) 
    let viewB = UIView() 
    addSubview(viewB) 
    viewB.translatesAutoresizingMaskIntoConstraints = false 
    viewB.topAnchor.constraint(equalTo: topAnchor).isActive = true 
    viewB.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true 
    viewB.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true 
    viewB.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true 
    viewB.heightAnchor.constraint(equalToConstant: 42).isActive = true 
}

这将导致以下错误：

2017-12-02 15:44:59.150228-0800 Ping[37511:5808904] [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. 
    (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSAutoresizingMaskLayoutConstraint:0x608000283b60 h=--& v=--& MyApp.ViewA:0x7fe606511360.height == 0 (active)>", 
    "<NSLayoutConstraint:0x608000282030 UIView:0x7fe606511550.height == 42 (active)>", 
    "<NSLayoutConstraint:0x608000281d60 V:|-(0)-[UIView:0x7fe606511550] (active, names: '|':MyApp.ViewA:0x7fe606511360)>", 
    "<NSLayoutConstraint:0x608000281ef0 UIView:0x7fe606511550.bottom == MyApp.ViewA:0x7fe606511360.bottom (active)>" 
) 
Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x608000282030 UIView:0x7fe606511550.height == 42 (active)> 
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. 
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

ViewA有一个非常简单的设置：

extension MessageViewController { 
    open override var canBecomeFirstResponder: Bool { 
     return true 
    } 
    open override var inputAccessoryView: UIView? { 
     return messageInputView 
    } 
}

为什么ViewA他我从来没有设置的ight突破了我设置的限制？

回答：

我认为解决的办法是禁用面具自动调整大小为ViewA：

viewA.translatesAutoresizingMaskIntoConstraints = false

既然你与约束铺设出来。现在它试图将您的ViewA的高度设置为0，从而导致问题。

以上是 UIView的高度约束打破子视图的高度约束 的全部内容， 来源链接： utcz.com/qa/258903.html

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