swift - ApplicationDidEnterBackground : NSTimer 时意外崩溃

Question

昨天，我问过，因为我的后台定时器有问题，我找到了一个解决方案让它工作，但现在，当我的应用程序进入后台时我遇到了问题。

在后台运行:

backgroundTaskIdentifier = UIApplication.shared.beginBackgroundTask(expirationHandler: {
        UIApplication.shared.endBackgroundTask(self.backgroundTaskIdentifier!)
    })

这是我的计时器:

let interval = 0.01
timer = Timer.scheduledTimer(timeInterval: interval, target: self, selector:#selector(ViewController.updateTimer), userInfo: nil, repeats: true)
RunLoop.main.add(timer, forMode: RunLoopMode.commonModes)

这是我的 updateTimer 函数:

func updateTimer () {
    var j = 0
    for _ in rows {
      if (rows[j]["Playing"] as! Bool == true ) {
            rows[j]["time"] = (rows[j]["time"] as! Double + interval) as AnyObject
            rows[j]["lastTime"] = (rows[j]["lastTime"] as! Double + interval) as AnyObject
      }
      if (rows[j]["lastTime"] as! Double > 60.0) {
            min[j] += 1
            rows[j]["lastTime"] = 0.00 as AnyObject
      }
      j += 1
    }
}

在我的 applicationDidEnterBackground 方法中，我调用了这个函数:

func backgroundTimer() {
    print("background") // This Print works fine
    timer.invalidate() // Never works
    interval = 1.00 // Crash when interval change from 0.01 to 1.00
    timer = Timer.scheduledTimer(timeInterval: interval, target: self, selector:#selector(ViewController.updateTimer), userInfo: nil, repeats: true)
}

这是我的应用程序进入后台时的输出:

The Double is interval.

In Info.plist I add : Application does not run in background : NO.

让我知道我做错了什么？

编辑:

Initialization of rows in viewDidLoad method

let i: [String : AnyObject] = ["time": time as AnyObject, "Playing": false as AnyObject, "lastTime": 0.00 as AnyObject, "lapNumber": 0 as AnyObject, "min": 0 as AnyObject]
rows.append(i as [String : AnyObject])

Answer 1

您的基本问题似乎是对并非真正对象的事物使用 AnyObject。它导致 as! Bool 表示失败。

这是一个 playground 片段，它通过允许字典中的简单值来取回存储的 Bool 值。

var rows: [[String : Any]] = []
let i: [String : Any] = ["time": time, "Playing": false, "lastTime": 0.00, "lapNumber": 0, "min": 0]
rows.append(i)

let playing = rows[0]["Playing"]
if let playing = playing as? Bool {
    print("Bool")
} else {
    print("Something else \(String(describing: playing))")
}