问题：
VFL 中如何表示规则应用于纵向
解决：
使用”V:”。
如： “V:|-[titleLabel]-|”
|
|
let views = ["titleLabel":titleLabel,"contentLabel":contentLabel] self.contentView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "|-[titleLabel]-|", options: [], metrics: nil, views: views)) self.contentView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "|-[contentLabel]-|", options: [], metrics: nil, views: views)) self.contentView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-[titleLabel]-[contentLabel]-|", options: [], metrics: nil, views: views)); |
参考：
http://www.jianshu.com/p/bab69690cb1a