傻瓜式自定義函數的CompletionHandler

Question

我在網上到處搜索，但無法真正處理我找到的答案。所以如果有人可以幫助我，這是值得讚賞的。

我寫了一個函數，看起來像這樣：我這樣稱呼它

func setImage(imageName: String, completion: ((String) -> Void)?) { 
    UIView.transitionWithView(self.myImageView, duration: 0.3, options: .CurveEaseOut, animations: { 
     self.lockImageView.image = UIImage(named: "\(imageName).png") 
     }, completion: { finished in 
      //execute the completionBlock that was passed 
    }) 
} 

：

setImage("lockCheck", completion: { finished in 
    print("done") 
}) 

現在，我該如何執行任何已爲完成過去？
在功能方面，在轉型的完成塊，我想是這樣

for x in completion {self.x} 

，但沒有奏效。

感謝提前:)

Answer 1

例如，你可以像這樣執行完成處理程序馬上在completionHandler動畫塊：

func setImage(imageName: String, completion: ((Bool) -> Void)?) { 
    UIView.transitionWithView(self.myImageView, duration: 0.3, options: .CurveEaseOut, animations: {() -> Void in 
      self.lockImageView.image = UIImage(named: "\(imageName).png") 
     }, completion: completion) 
} 

您也可以運行帶有額外參數的完成處理喜歡以下（我希望這是很清楚）：

func setImage(imageName: String, completion: ((Bool, String) -> Void)?) { 
    UIView.transitionWithView(self.lockImageView, duration: 0.3, options: .CurveEaseOut, animations: {() -> Void in 
     self.lockImageView.image = UIImage(named: "\(imageName).png") 
      }) { (finished) -> Void in 

      // Do some things for example print 
      print("Hi, this is the animation completion handler") 

      // Notice the ? because the completion handler is an optional 
      completion?(finished, "some string") 

    } 
}