在 switch 语句中使用多个 case

Question

我正在尝试在三个按钮操作上使用 switch 语句，用户可以在早上、下午和晚上时间之间进行选择。我想根据选择的按钮更改背景和文本颜色。

现在我的按钮没有根据点击而改变，我需要做什么才能让它工作？另外，在其中一种情况下，我如何使用标签 10 和标签 20？谢谢。

// 我的按钮

    private lazy var morningButton: TimeButton = {
        let button = TimeButton(type: .system)
        button.setTitle("Morning", for: .normal)
        button.titleLabel?.font = UIFont(name: "AvenirNext-Medium", size: 14)
        return button
    }()
    
    private lazy var afternoonButton: TimeButton = {
        let button = TimeButton(type: .system)
        button.setTitle("Afternoon", for: .normal)
        button.titleLabel?.font = UIFont(name: "AvenirNext-Medium", size: 14)
        return button
    }()
    
    private lazy var eveningButton: TimeButton = {
        let button = TimeButton(type: .system)
        button.setTitle("Evening", for: .normal)
        button.titleLabel?.font = UIFont(name: "AvenirNext-Medium", size: 14)
        return button
    }()

// 切换语句

@objc func timeButtonsTapped(_ sender: TimeButton) {
        
        switch sender.tag {
        case 10:
            morningButton.backgroundColor = .darkPurpleTint
            morningButton.setTitleColor(.white, for: .normal)
            afternoonButton.backgroundColor = .white
            afternoonButton.setTitleColor(.darkPurpleTint, for: .normal)
            eveningButton.backgroundColor = .white
            eveningButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 20:
            afternoonButton.backgroundColor = .darkPurpleTint
            afternoonButton.setTitleColor(.white, for: .normal)
            morningButton.backgroundColor = .white
            morningButton.setTitleColor(.darkPurpleTint, for: .normal)
            eveningButton.backgroundColor = .white
            eveningButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 30:
            eveningButton.backgroundColor = .darkPurpleTint
            eveningButton.setTitleColor(.white, for: .normal)
            morningButton.backgroundColor = .white
            morningButton.setTitleColor(.darkPurpleTint, for: .normal)
            afternoonButton.backgroundColor = .white
            afternoonButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 10 & 20:
            morningButton.backgroundColor = .darkPurpleTint
            morningButton.setTitleColor(.white, for: .normal)
            afternoonButton.backgroundColor = .darkPurpleTint
            afternoonButton.setTitleColor(.white, for: .normal)
            eveningButton.backgroundColor = .white
            eveningButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 10 & 30:
            morningButton.backgroundColor = .darkPurpleTint
            morningButton.setTitleColor(.white, for: .normal)
            eveningButton.backgroundColor = .darkPurpleTint
            eveningButton.setTitleColor(.white, for: .normal)
            afternoonButton.backgroundColor = .white
            afternoonButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 20 & 30:
            afternoonButton.backgroundColor = .darkPurpleTint
            afternoonButton.setTitleColor(.white, for: .normal)
            eveningButton.backgroundColor = .darkPurpleTint
            eveningButton.setTitleColor(.white, for: .normal)
            morningButton.backgroundColor = .white
            morningButton.setTitleColor(.darkPurpleTint, for: .normal)
        case 10 & 20 & 30:
            morningButton.backgroundColor = .darkPurpleTint
            morningButton.setTitleColor(.white, for: .normal)
            afternoonButton.backgroundColor = .darkPurpleTint
            afternoonButton.setTitleColor(.white, for: .normal)
            eveningButton.backgroundColor = .darkPurpleTint
            eveningButton.setTitleColor(.white, for: .normal)
        default:
            morningButton.backgroundColor = .white
            morningButton.setTitleColor(.darkPurpleTint, for: .normal)
            afternoonButton.backgroundColor = .white
            afternoonButton.setTitleColor(.darkPurpleTint, for: .normal)
            eveningButton.backgroundColor = .white
            eveningButton.setTitleColor(.darkPurpleTint, for: .normal)
        }
        
    }

// 我的功能

fileprivate func configureUI() {

        morningButton.tag = 10
        morningButton.isUserInteractionEnabled = true
        afternoonButton.tag = 20
        afternoonButton.isUserInteractionEnabled = true
        eveningButton.tag = 30
        eveningButton.isUserInteractionEnabled = true
        
        morningButton.addTarget(self, action: #selector(timeButtonsTapped(_:)), for: .touchUpInside)
        afternoonButton.addTarget(self, action: #selector(timeButtonsTapped(_:)), for: .touchUpInside)
        eveningButton.addTarget(self, action: #selector(timeButtonsTapped(_:)), for: .touchUpInside)

}

Answer 1

您不需要将按钮着色逻辑分布在您的视图控制器中。这会导致大量的代码重复和未来的可维护性差。

UIButton 有一个isSelected 属性，您可以在这种特殊情况下使用它来保存按钮的状态。另外我建议将所有颜色移动到按钮的子类中，这样客户就不必担心它们了。该按钮应负责切换其颜色。

TimeButton 类如下所示：

class TimeButton: UIButton {
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setup()
    }
    
    override var isSelected: Bool {
        didSet {
            updateBackgroundColor()
        }
    }
    
    // MARK: - Private
    private func setup() {
        translatesAutoresizingMaskIntoConstraints = false
        setTitleColor(.white, for: .normal)
        setTitleColor(.systemPurple, for: .selected)
        titleLabel?.font = UIFont(name: "AvenirNext-Medium", size: 14)
        updateBackgroundColor()
    }
    
    private func updateBackgroundColor() {
        backgroundColor = isSelected ? .white : .systemPurple
    }
}

您的视图控制器现在应该如下所示：

class ViewController: UIViewController {
    private lazy var morningButton: TimeButton = {
        let button = TimeButton(type: .custom)
        button.setTitle("Morning", for: .normal)
        button.addTarget(self, action: #selector(didSelectButton(_:)), for: .touchUpInside)
        return button
    }()
    
    private lazy var afternoonButton: TimeButton = {
        let button = TimeButton(type: .custom)
        button.setTitle("Afternoon", for: .normal)
        button.addTarget(self, action: #selector(didSelectButton(_:)), for: .touchUpInside)
        return button
    }()
    
    private lazy var eveningButton: TimeButton = {
        let button = TimeButton(type: .custom)
        button.setTitle("Evening", for: .normal)
        button.addTarget(self, action: #selector(didSelectButton(_:)), for: .touchUpInside)
        return button
    }()
    
    @objc private func didSelectButton(_ button: TimeButton) {
        button.isSelected = !button.isSelected
        // do some additional stuff if needed
    }
}

注意按钮初始化中的type: .custom - 这将在选择按钮时禁用默认按钮样式。

如果您想获取某个按钮的值 - 只需参考其isSelected 属性：

let shouldUseMorningTime = morningButton.isSelected