NSLayoutConstraint在swift中

我想将以下代码转换为Swift：

leftConstraint = [NSLayoutConstraint constraintWithItem:self.contentView attribute:NSLayoutAttributeLeft relatedBy:0 toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1.0 constant:0]; [self.view addConstraint:leftConstraint]; 

有人能给我新的语法在Swift中做到吗？

Answer 1

从文档中复制并粘贴：

 convenience init(item view1: AnyObject!, attribute attr1: NSLayoutAttribute, relatedBy relation: NSLayoutRelation, toItem view2: AnyObject!, attribute attr2: NSLayoutAttribute, multiplier multiplier: CGFloat, constant c: CGFloat) 

所以你的代码转换为

 let leftConstraint = NSLayoutConstraint(item: self.contentView, attribute: .left, relatedBy: .equal, toItem: self.view, attribute: .left, multiplier: 1.0, constant: 0.0); self.view.addConstraint(leftConstraint); 

代码已更新为Swift 4。

Answer 2

尝试这个：

 var leftConstrains:NSLayoutConstraint = NSLayoutConstraint(item: self.contentView, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.Equal, toItem: self.contentView, attribute: NSLayoutAttribute.Left, multiplier: 1, constant: 0) self.contentView.addConstraint(leftConstrains)