中心UIView没有重叠不同大小的邻居意见？

Question

我想实现什么，他们三个人都UILabels：

规格：

1. left和right修边UIViews。
2. middle居中，即使侧视图的大小不一样。
3. 在middle和left或middle和right之间的碰撞，在middle文本被截断尾巴而left和right不会改变。

问题：

我已经不能满足（2），并在同一时间（3）这两个要求。

• （2）与middle.autoAlignAxisToSuperviewAxis(.Vertical)
  • 问题来实现的：没有截断，它只是重叠leftLabel和rightLabel。
• （3）用middle.autoPinEdge(.Left, toEdge: .Right, ofView: leftLabel)和rightLabel的相同策略实现。
  • 问题：middle集中在leftLabel和rightLabel之间的区域，如果最后两不具有相同的大小，middle没有的SuperView了居中。

两个应用创建一个约束冲突，我不知道如何解决它，所以我的问题：

我如何中心一个UILabel并截断它avoir与重叠的侧视图。不同的尺寸？

Answer 1

您只需要添加两个约束，一个是中间和左边之间的水平间距，将关系设置为'大于或等于'，并且常量为例如10;另一个是中间和右边之间的水平间距，像约束一样的配置。

当中间标签的文本太长时，下面的约束将防止中间标签与标签左右重叠。

添加示例代码：
我想你已经设置的约束UILabel左右在故事板或代码。下面的示例用于configu UILabel中间

func setupConstraint() { 
    self.middle = UILabel() 
    self.middle!.backgroundColor = UIColor.yellowColor() 
    self.view.addSubview(self.middle!) 
    self.middle!.numberOfLines = 0 
    self.middle!.translatesAutoresizingMaskIntoConstraints = false 
    let middle = self.middle! 
    var constraint = NSLayoutConstraint(item: middle, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: left, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 0) 

    self.view.addConstraint(constraint) 

    constraint = NSLayoutConstraint(item: middle, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.GreaterThanOrEqual, toItem: left, attribute: NSLayoutAttribute.Right, multiplier: 1, constant: 10) 

    self.view.addConstraint(constraint) 

    constraint = NSLayoutConstraint(item: right, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.GreaterThanOrEqual, toItem: middle, attribute: NSLayoutAttribute.Right, multiplier: 1, constant: 10) 
    constraint.priority = 1000 

    self.view.addConstraint(constraint) 

    constraint = NSLayoutConstraint(item: middle, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0) 

    self.view.addConstraint(constraint) 

    constraint = NSLayoutConstraint(item: middle, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.GreaterThanOrEqual, toItem: middle, attribute: NSLayoutAttribute.Height, multiplier: 1, constant: 100) 

    self.view.addConstraint(constraint) 

    self.middle!.text = "self.middle.translatesAutoresizingMaskIntoConstraints = false" 
} 

Sanpshot

Answer 2

我试图设置在游乐场的溶液：

import UIKit 
import XCPlayground 

let viewController = UIViewController() 
XCPlaygroundPage.currentPage.liveView = viewController.view 

viewController.view.backgroundColor = UIColor.whiteColor() 

let leftView = UIView() 
leftView.translatesAutoresizingMaskIntoConstraints = false 
leftView.backgroundColor = UIColor.greenColor() 
let leftLabel = UILabel() 
leftLabel.translatesAutoresizingMaskIntoConstraints = false 
leftLabel.text = "leftleftleftleftleftleftleftleftleftleftleftleftleftleft" 
leftView.addSubview(leftLabel) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-2-[leftLabel]-2-|", options: [], metrics: nil, views: ["leftLabel": leftLabel])) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-2-[leftLabel]-2-|", options: [], metrics: nil, views: ["leftLabel": leftLabel])) 

let middleView = UIView() 
middleView.translatesAutoresizingMaskIntoConstraints = false 
middleView.backgroundColor = UIColor.redColor() 
let middleLabel = UILabel() 
middleLabel.translatesAutoresizingMaskIntoConstraints = false 
middleLabel.setContentCompressionResistancePriority(UILayoutPriorityDefaultLow, forAxis: .Horizontal) 
middleLabel.text = "middle" 
middleView.addSubview(middleLabel) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-2-[middleLabel]-2-|", options: [], metrics: nil, views: ["middleLabel": middleLabel])) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-2-[middleLabel]-2-|", options: [], metrics: nil, views: ["middleLabel": middleLabel])) 

let rightView = UIView() 
rightView.translatesAutoresizingMaskIntoConstraints = false 
rightView.backgroundColor = UIColor.greenColor() 
let rightLabel = UILabel() 
rightLabel.translatesAutoresizingMaskIntoConstraints = false 
rightLabel.text = "right" 
rightView.addSubview(rightLabel) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-2-[rightLabel]-2-|", options: [], metrics: nil, views: ["rightLabel": rightLabel])) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-2-[rightLabel]-2-|", options: [], metrics: nil, views: ["rightLabel": rightLabel])) 

viewController.view.addSubview(leftView) 
viewController.view.addSubview(middleView) 
viewController.view.addSubview(rightView) 

NSLayoutConstraint(item: middleView, attribute: .CenterX, relatedBy: .Equal, toItem: viewController.view, attribute: .CenterX, multiplier: 1, constant: 0).active = true 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[leftView]->=8-[middleView]->=8-[rightView]|", options: [.AlignAllTop, .AlignAllBottom], metrics: nil, views: ["leftView": leftView, "middleView": middleView, "rightView": rightView])) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[leftView]", options: [], metrics: nil, views: ["leftView": leftView])) 

结果像这样：

UPDATE（没有嵌入自己的看法标签）：

import UIKit 
import XCPlayground 

let viewController = UIViewController() 
XCPlaygroundPage.currentPage.liveView = viewController.view 

viewController.view.backgroundColor = UIColor.whiteColor() 

let leftLabel = UILabel() 
leftLabel.translatesAutoresizingMaskIntoConstraints = false 
leftLabel.backgroundColor = UIColor.greenColor() 
leftLabel.text = "leftleftleftleftleftleftleftleftleftleftleftleftleftleft" 

let middleLabel = UILabel() 
middleLabel.translatesAutoresizingMaskIntoConstraints = false 
middleLabel.setContentCompressionResistancePriority(UILayoutPriorityDefaultLow, forAxis: .Horizontal) 
middleLabel.backgroundColor = UIColor.redColor() 
middleLabel.text = "middle" 

let rightLabel = UILabel() 
rightLabel.translatesAutoresizingMaskIntoConstraints = false 
rightLabel.backgroundColor = UIColor.greenColor() 
rightLabel.text = "right" 

viewController.view.addSubview(leftLabel) 
viewController.view.addSubview(middleLabel) 
viewController.view.addSubview(rightLabel) 

NSLayoutConstraint(item: middleLabel, attribute: .CenterX, relatedBy: .Equal, toItem: viewController.view, attribute: .CenterX, multiplier: 1, constant: 0).active = true 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[leftLabel]->=8-[middleLabel]->=8-[rightLabel]|", options: [.AlignAllTop, .AlignAllBottom], metrics: nil, views: ["leftLabel": leftLabel, "middleLabel": middleLabel, "rightLabel": rightLabel])) 
NSLayoutConstraint.activateConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[leftLabel]", options: [], metrics: nil, views: ["leftLabel": leftLabel])) 

希望它能帮助:)