访问 Xcode 按钮文本但未反映背景更改 UI答案

【问题标题】：Xcode button text is accessed but the background change UI is not reflected访问 Xcode 按钮文本但未反映背景更改 UI
【发布时间】：2020-07-13 10:49:54
【问题描述】：

我创建了一个特殊按钮，如下所示。单击时我可以访问文本值，但是当我更改背景值时，UI 没有任何变化。有谁知道为什么？

class MyButton: UIButton {
            
    override func layoutSubviews() {
        super.layoutSubviews()
        
        layer.cornerRadius = 8
        titleLabel?.adjustsFontSizeToFitWidth = true
        contentHorizontalAlignment = .center
        
        titleLabel?.textColor = .white
        backgroundColor = .black
        
        addGestureRecognizer(UITapGestureRecognizer(target: self, action:  #selector (self.someAction (_:))))
                               
    }
    
    @objc func someAction(_ sender:UITapGestureRecognizer) {
        print(titleLabel!.text) // text accessible and printed

        titleLabel?.textColor = .black //no change
        backgroundColor = .white //no change
    }
}

【问题讨论】：

标签： ios swift xcode uigesturerecognizer layoutsubviews

【解决方案1】：

请从 layoutSubviews 中删除这两行

        titleLabel?.textColor = .white
        backgroundColor = .black

这样添加

override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func  commonInit() {
        layer.cornerRadius = 8
        titleLabel?.adjustsFontSizeToFitWidth = true
        contentHorizontalAlignment = .center
        
        titleLabel?.textColor = .white
        backgroundColor = .black
        
        addGestureRecognizer(UITapGestureRecognizer(target: self, action:  #selector (self.someAction (_:))))
    }

【讨论】：