UIButton 约束失败，但适用于 UILabel

Posted 2023-02-23

【中文标题】UIButton 约束失败，但适用于 UILabel

【英文标题】：UIButton Constraint Failure, but works with UILabel

【发布时间】：2016-04-30 06:29:57

【问题描述】：

我正在尝试将按钮实用地添加到 UIView。此代码将与 UI 标签一起使用，但在将其与按钮一起使用时，约束会失败。我怎样才能使这项工作？谢谢。

let homeButton =  UIButton(frame: CGRectZero)
    homeButton.setTitle("Home", forState: .Normal)
    homeButton.titleLabel!.textAlignment = NSTextAlignment.Center
    homeButton.titleLabel!.textColor = UIColor.whiteColor()
    homeButton.titleLabel!.translatesAutoresizingMaskIntoConstraints = false
    containerView.addSubview(homeButton)

    let buttonWidthConstraint = NSLayoutConstraint(item: homeButton, attribute: .Width, relatedBy: .Equal, toItem: self.containerView, attribute: .Width, multiplier: 0.5, constant: 0)
    containerView.addConstraint(buttonWidthConstraint)
    let buttonHeightConstraint = NSLayoutConstraint(item: homeButton, attribute: .Height, relatedBy: .Equal, toItem: self.containerView, attribute: .Height, multiplier: 0.5,constant: 0)
    containerView.addConstraint(buttonHeightConstraint)

    let buttonXConstraint = NSLayoutConstraint(item: homeButton, attribute: .CenterX, relatedBy: .Equal, toItem: self.containerView, attribute: .CenterX, multiplier: 1, constant: 0)
    let buttonYConstraint = NSLayoutConstraint(item: homeButton, attribute: .CenterY, relatedBy: .Equal, toItem: self.containerView, attribute: .CenterY, multiplier: 1, constant: 0)
    containerView.addConstraint(buttonXConstraint)
    containerView.addConstraint(buttonYConstraint)

【问题讨论】：

使用homeButton.translatesAutoresizingMaskIntoConstraints = false

那行得通。谢谢

【参考方案1】：

您应该使用homeButton.translatesAutoresizingMaskIntoConstraints = false 而不是homeButton.titleLabel!.translatesAutoresizingMaskIntoConstraints = false。

因为您应该禁用 button 的自动调整掩码而不是按钮的 titleLabel ！！！

希望这会有所帮助:)