我添加了领先 |尾随|顶部 |高度限制,但视图不可见。
let view = UIView()
view.backgroundColor = .orange
self.addSubview(view)
NSLayoutConstraint.activate([
view.leadingAnchor.constraint(equalTo: self.leadingAnchor),
view.trailingAnchor.constraint(equalTo: self.trailingAnchor),
view.topAnchor.constraint(equalTo: self.topAnchor, constant: 100),
view.heightAnchor.constraint(equalToConstant: 300)
])
答案 0 :(得分:4)
将视图添加为子视图时,您的代码应禁用 translatesAutoresizingMaskIntoConstraints
。这意味着系统不会创建一组约束来复制视图的自动调整大小掩码指定的行为。
假设您的约束是正确的,您应该会在将该属性设置为 false 后看到您的视图。
let view = UIView()
view.backgroundColor = .orange
view.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(view)
NSLayoutConstraint.activate([
view.leadingAnchor.constraint(equalTo: self.leadingAnchor),
view.trailingAnchor.constraint(equalTo: self.trailingAnchor),
view.topAnchor.constraint(equalTo: self.topAnchor, constant: 100),
view.heightAnchor.constraint(equalToConstant: 300)
])