我該如何製作一個以hh：mm：ss計算的Swift 3.0計時器：ms

Question

我遵循DuncanC的解決方案Swift timer in milliseconds。下面的代碼：

startTime = NSDate.timeIntervalSinceReferenceDate 
Timer.scheduledTimer(timeInterval: 0.02, 
              target: self, 
              selector: Selector(("advanceTimer:")), 
              userInfo: nil, 
              repeats: true) 


func advanceTimer(timer: Timer) 
{ 
    //Total time since timer started, in seconds 
    self.time = NSDate.timeIntervalSinceReferenceDate - startTime 
    //The rest of your code goes here 
} 

的Xcode建議我改變NSDate.timeIntervalSinceReferenceDate()到NSDate.timeIntervalSinceReferenceDate和startTime: NSTimeInterval到startTime: TimeInterval爲雨燕3.0。 我的代碼產生錯誤：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MyGame.GameScene advanceTimer:]: unrecognized selector sent to instance

Answer 1

在斯威夫特3 Selector語法變化，現在你需要傳遞的第一個參數標籤用你的行動，你的selector應該像#selector(self.advanceTimer(timer:))。

Timer.scheduledTimer(timeInterval: 0.02, 
        target: self, 
        selector: #selector(self.advanceTimer(timer:)), 
        userInfo: nil, 
        repeats: true) 

Answer 2

advanceTimer(timer:)應區別宣佈根據Swift API Design Guidelines，您應該使用雨燕的本地Date，而不是NSDate和選擇的語法已經更改，因此您的代碼將現在這樣寫：

startTime = NSDate.timeIntervalSinceReferenceDate 
Timer.scheduledTimer(timeInterval: 0.02, 
        target: self, 
        selector: #selector(advanceTimer), 
        userInfo: nil, 
        repeats: true) 

func advanceTimer(_ timer: Timer) 
{ 
    //Total time since timer started, in seconds 
    self.time = NSDate.timeIntervalSinceReferenceDate - startTime 
    //The rest of your code goes here 
} 

而且，Timer有新的基於關閉的方法，因此您現在可以將整個事件縮減爲：

startTime = NSDate.timeIntervalSinceReferenceDate 
Timer.scheduledTimer(withTimeInterval: 0.02, repeats: true) { timer in 
    //Total time since timer started, in seconds 
    self.time = NSDate.timeIntervalSinceReferenceDate - startTime 
    //The rest of your code goes here 
}