layoutMarginsGuide产生不必要的前导和尾随边距

Question

我正在以编程方式在我的视图上创建约束。当我尝试使用layoutMarginsGuide定位符时，顶部和底部定位符会按预期工作，但是即使将insets设置为0，前导和尾端定位符也会创建边距。是什么造成了这些不需要的边距，以及如何正确设置它们？

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemRed
        view.directionalLayoutMargins = NSDirectionalEdgeInsets(top: 0, leading: 0, bottom: 0, trailing: 0)


        let childView = UIView(frame: .zero)
        childView.backgroundColor = .systemIndigo
        childView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(childView)
        NSLayoutConstraint.activate([
            childView.topAnchor.constraint(equalTo: view.layoutMarginsGuide.topAnchor),
            childView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor),
            childView.leadingAnchor.constraint(equalTo: view.layoutMarginsGuide.leadingAnchor),
            childView.trailingAnchor.constraint(equalTo: view.layoutMarginsGuide.trailingAnchor),
        ])
}

Answer 1

因此，侧面约束不包含空格，并且完全粘贴到侧面，您必须删除layoutMarginsGuide，就像：

NSLayoutConstraint.activate([
      childView.topAnchor.constraint(equalTo: view.layoutMarginsGuide.topAnchor),
      childView.bottomAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor),
      childView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
      childView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
])