使用Swift/Xcode重新打开应用时维护按钮状态

@IBOutlet weak var button1: UIButton!
@IBOutlet weak var button2: UIButton!
// 其他按钮...

override func viewDidLoad() {
    super.viewDidLoad()
    
    // 读取保存的按钮状态
    let button1State = UserDefaults.standard.bool(forKey: "Button1State")
    let button2State = UserDefaults.standard.bool(forKey: "Button2State")
    // 其他按钮...
    
    // 设置按钮的状态
    button1.isSelected = button1State
    button2.isSelected = button2State
    // 其他按钮...
}

@IBAction func button1Tapped(_ sender: UIButton) {
    sender.isSelected = !sender.isSelected
    UserDefaults.standard.set(sender.isSelected, forKey: "Button1State")
}

@IBAction func button2Tapped(_ sender: UIButton) {
    sender.isSelected = !sender.isSelected
    UserDefaults.standard.set(sender.isSelected, forKey: "Button2State")
}

// 其他按钮...