如何以编程方式进行此自动布局？

Question

如何为所有设备制作标签自动布局。

        golabel = UILabel(frame: CGRectMake(30, 100, 350, 100))
        golabel.text = "Game Over"
        golabel.textColor = UIColor.whiteColor()
        golabel.font = UIFont(name: "AppleSDGothicNeo-Thin" , size: 70)
        self.view.addSubview(golabel)

Answer 1

let golabel = UILabel()

golabel.setTranslatesAutoresizingMaskIntoConstraints(false)

let horizontalConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 30)
view.addConstraint(horizontalConstraint)

let verticalConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 100)
view.addConstraint(verticalConstraint)

let widthConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 350)
golabel.addConstraint(widthConstraint)

let heightConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 100)
golabel.addConstraint(heightConstraint)

Answer 2

将标签添加为子视图后，您需要避免自动布局将自动调整蒙版转换为约束，否则您可能会发生冲突。

golabel.setTranslatesAutoresizingMaskIntoConstraints(false)

在这里添加约束

 let horizontalConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    self.view.addConstraint(horizontalConstraint)

let verticalConstraint = NSLayoutConstraint(item: golabel, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
    self.view.addConstraint(verticalConstraint)

由于您没有添加禁止标签增长的约束，标签将使用其内在内容大小，因此它可以根据文本的长度和字体无限增长。