ios - UIButton 宽度的自动布局问题

Question

    signUpButton.translatesAutoresizingMaskIntoConstraints = false
    signUpButton.widthAnchor.constraint(equalToConstant: 128).isActive = true
    signUpButton.heightAnchor.constraint(equalToConstant: 64).isActive = true
    signUpButton.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    signUpButton.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
    signUpButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)

• NSLayoutConstraint: UIButton:'注册'.width == 128(事件)，
• NSLayoutConstraint:H:|-(0)-[UIButton:'注册'](事件，名称:'|':UIView:)，
• NSLayoutConstraint: UIButton:'注册'.trailing == UIView:.trailing(事件)，
• NSLayoutConstraint:“UIView-Encapsulated-Layout-Width”UIView:.width == 375(事件)

将尝试通过打破约束来恢复NSLayoutConstraint: UIButton:'注册'.width == 128 (事件)>

我想将按钮放在具有一定宽度的前导和尾随 anchor 的中心，但是当我运行代码时，按钮会扩展到这些 anchor 。我怎样才能阻止这种扩张？

Answer 1

由于您似乎希望将按钮在 view 内水平居中，因此您需要替换:

signUpButton.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
signUpButton.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true

与:

signUpButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true