如何在ActionScript

Question

使用回調

所以我們可以說我有以下代碼：

public function first(text:String):String { 
    _text = text; 
    dispatchEvent(event); 

    //Want this statement to return the value of _text 
    //after handler has finished transforming text. 
    return _text; 
} 

//handles the event 
public function handler(event:Event):void { 
    //does things, then changes the value of _text 
    _text = "next text that first needs to return"; 
} 

我將如何確保方法（第一）返回_text的正確的價值已經被改造後（處理） ？

預先感謝您！

Answer 1

由於ActionScript是單線程語言，事件處理程序不返回值我假設如果_text在程序包範圍內變量，您的代碼將工作。接下來的代碼不作大的意義，但如果你從另一個類調用first功能，它可以是有用

package 
{ 
    import flash.display.Sprite; 
    import flash.events.Event; 


    public class EventTest extends Sprite 
    { 
     public function EventTest() 
     { 
      addEventListener("sliceText", sliceHandler); 

      //will be Some 
      var newText:String = first("SomeText"); 
      trace(newText); 
     } 

     private var _text:String; 

     public function first(text:String):String 
     { 
      _text = text; 

      dispatchEvent(new Event("sliceText")); 

      return _text; 
     } 

     protected function sliceHandler(event:Event):void 
     { 
      //let's slice text to be more valuable 
      _text = _text.slice(0,4); 
     } 

    } 
}