傻瓜式自定义函数的CompletionHandler

Question

我在网上到处搜索，但无法真正处理我找到的答案。所以如果有人可以帮助我，这是值得赞赏的。

我写了一个函数，看起来像这样：我这样称呼它

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") 
}) 

现在，我该如何执行任何已为完成过去？
在功能方面，在转型的完成块，我想是这样

for x in completion {self.x} 

，但没有奏效。

感谢提前:)

Answer 1

例如，你可以像这样执行完成处理程序马上在completionHandler动画块：

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) 
} 

您也可以运行带有额外参数的完成处理喜欢以下（我希望这是很清楚）：

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") 

    } 
}