可视化格式语言，按钮宽度和高度约束

Question

有没有办法用NSLayoutConstraints设置UIView的宽度和高度？ 例如，我有以下约束设置

subView.setTranslatesAutoresizingMaskIntoConstraints(false);
        let cons:NSArray =   NSLayoutConstraint.constraintsWithVisualFormat("[subView(99)]", options:nil, metrics: nil, views: ["subView":subView]);
        self.view.addConstraints(cons);

这只设置宽度，如何添加高度？

Answer 1

两种可能的选择：

[view setTranslatesAutoresizingMaskIntoConstraints:NO];
NSArray* vConstraints = [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[view(25)]|" options:0 metrics:nil views:view]];
[parentView addConstraints:vConstraints];

或

NSLayoutConstraint* vConstraint = [NSLayoutConstraint constraintWithItem:view attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:25];
[parentView addConstraint:vConstraint];

Answer 2

对于垂直布局，只需将 V：添加到VFL字符串的开头：

  subView.setTranslatesAutoresizingMaskIntoConstraints(false);

  let horizontalCons:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("[subView(99)]", options:nil, metrics: nil, views: ["subView":subView]);
  let veritcleCons:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("V:[subView(50)]", options:nil, metrics: nil, views: ["subView":subView]);

  self.view.addConstraints(horizontalCons);
  self.view.addConstraints(veritcleCons);