高度不明确

Question

使用Xcode 8.0(8A218a)

我得到"高度暧昧".即使(在我看来)我在Y轴上都有约束.

视图内的两个子视图都具有高度(一个具有高度作为约束,一个具有内部内容大小).

请参阅下图,了解"调试视图层次结构"的用途.

使用以下代码在代码中创建约束:

标签是UILabel,下划线是UIView

label.translatesAutoresizingMaskIntoConstraints = false
underline.translatesAutoresizingMaskIntoConstraints = false

addSubview(label)
addSubview(underline)

label.topAnchor.constraint(equalTo: topAnchor).isActive = true
label.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
label.rightAnchor.constraint(equalTo: rightAnchor).isActive = true

label.bottomAnchor.constraint(equalTo: underline.topAnchor, constant: -5).isActive = true

underline.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
underline.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
underline.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true

underline.heightAnchor.constraint(equalToConstant: 2.0).isActive = true

这是从有问题的项目中提取的示例项目:https: //github.com/everlof/LayoutIssue