ios - 单例 SharedInstance 函数被调用两次

Question

所有单例函数都是两次调用。“Prova”函数和定时器的选择器是两次调用。

class Timer {
    static let sharedInstanceTimer = Timer()
    var TimerCounter : NSTimer = NSTimer()
    var Counter : Int = Int()
    var TimerGameOver : Int = Int()
    var TimerBonusMultipleCircle : Int = Int()
    var TimerBonusBigCircle : Int = Int()
    var TimerCounterInterval : NSTimeInterval = 1

    init()
    {
        self.Counter = 60
        self.TimerGameOver = 10
        self.TimerBonusMultipleCircle = 5
        self.TimerBonusBigCircle = 5
        self.TimerCounterInterval = 1
    }
    func StartTimerCounter()
    {
        self.TimerCounter = NSTimer.scheduledTimerWithTimeInterval(self.TimerCounterInterval, target: Game.sharedInstanceGame, selector: #selector(Game.sharedInstanceGame.UpdateAllCounter), userInfo: nil, repeats: true)
    }
    func StopTimerCounter()
    {
        self.TimerCounter.invalidate()
    }
}

然后...在另一个文件中，我调用了 StartTimerCounter()

import UIKit
class FirstViewController: UIViewController {
    static let sharedInstanceFirstViewController = FirstViewController()
    override func viewDidLoad() {
        super.viewDidLoad()
        let backButton = UIBarButtonItem(title: "00:00:60", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
        backButton.tintColor = UIColor.whiteColor()
        navigationItem.leftBarButtonItem = backButton
        Circle.sharedInstanceCircle.CreateCircle()
        view.layer.addSublayer(Circle.sharedInstanceCircle.PrincipalCircle)
        Game.sharedInstanceGame.Play()


        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func prefersStatusBarHidden() -> Bool {
        return true
    }

    func ReturnToMenu()
    {
       navigationController?.popViewControllerAnimated(true)
    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

抛开我按照下面的建议更正的各种错误，我尝试了几种解决方案，但我找不到解决这个问题的方法。

Answer 1

几个想法:

1. 您的 sharedInstanceTimer 正在实例化 Timer(它本身就是一个 NSTimer)。它不应该是 NSTimer 的子类。

2. 然后您将 TimerCounter 初始化为您从未使用过的第二个计时器。

3. 上面会实例化两个定时器。然后，您将拥有 StartTimerCounter，它会在您每次调用它时实例化另一个 NSTimer。假设您只需要一个计时器，您应该让 StartTimerCounter 在启动新计时器之前使任何先前的计时器无效。

4. 我将此类称为 TimerManager 或类似名称，以避免与 Swift 3 类型 Timer 发生冲突。

5. 方法名称应以小写字母开头，属性也应如此。本着 Swift 3 API 指南的精神，您可能也想缩短方法名称。

6. 此外，如果您要定义一个单例，我会声明一个 private init() 初始化程序，以防止其他类意外地实例化另一个 TimerManager 对象。

所以，这会产生如下内容:

class TimerManager {
    static let shared = TimerManager()

    private var timer: NSTimer?   // this certainly should be private

    // whether you make these private or not, or constants vs properties, is up to you

    private var tounter : Int = 60
    private var timerGameOver : Int = 10
    private var timerBonusMultipleCircle : Int = 5
    private var timerBonusBigCircle : Int = 5
    private var timerCounterInterval : NSTimeInterval = 1

    // make sure no one else accidentally instantiates another TimerManager

    private init() {
    }

    /// Start timer.

    func startTimer() {
        stopTimer()    // cancel prior timer, if any

        timer = NSTimer.scheduledTimerWithTimeInterval(timerCounterInterval, target: Game.sharedInstanceGame, selector: #selector(Game.sharedInstanceGame.updateAllCounter), userInfo: nil, repeats: true)

        Game.sharedInstanceGame.prova()
    }

    /// Stop timer.

    func stopTimer() {
        timer?.invalidate()
        timer = nil
    }
}

---

这里有一个不相关的更深入的观察:我建议您将计时器对象与 Game 对象保持松散耦合。所以，我会从这个类中删除所有与“游戏”相关的内容:

class TimerManager {
    static let shared = TimerManager()

    private var timer: NSTimer?   // this certainly should be private
    private var timerHandler: (() -> ())?

    // whether you make these private or not, or constants vs properties, is up to you

    private var timerCounterInterval: NSTimeInterval = 1

    // make sure no one else accidentally instantiates another TimerManager

    private init() {
    }

    /// Start timer.
    ///
    /// - parameter timerHandler: The closure that will be called once per second.

    func startTimer(timerHandler: () -> ()) {
        stopTimer()    // cancel prior timer, if any

        self.timerHandler = timerHandler
        timer = NSTimer.scheduledTimerWithTimeInterval(timerCounterInterval, target: self, selector: #selector(handleTimer(_:)), userInfo: nil, repeats: true)
    }

    @objc func handleTimer(timer: NSTimer) {
        timerHandler?()
    }

    /// Stop timer.

    func stopTimer() {
        timer?.invalidate()
        timerHandler = nil
        timer = nil
    }
}

然后，当 Game 对象想要启动计时器时，它可能会这样做:

TimerManager.shared.startTimer {
    self.updateAllCounter()
}
prova()

现在，也许您出于这个问题的目的简化了您的计时器对象，并且这个 TimerManager 对象可能还需要更多的东西(正如所有这些其他属性所建议的那样，这些属性在您的代码片段)，但希望这能说明基本思想:TimerManager 不应参与调用任何特定 Game 方法等的业务。它应该简单地提供一种机制，调用者可以通过该机制简单地提供计时器应定期调用的代码块。