访问 Xcode 按钮文本但未反映背景更改 UI

Posted 2023-03-13

【中文标题】访问 Xcode 按钮文本但未反映背景更改 UI

【英文标题】：Xcode button text is accessed but the background change UI is not reflected

【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
    

【参考方案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 (_:))))