将参数传递给Complete Event - Adob​​e Flex

Question

我正在使用HTTP请求以二进制格式下载图像。下载完成后，我想处理它，但我也想将图像的ID传递给完整的处理函数......这是怎么做的？

var loader:URLLoader = new URLLoader();

for(var i:int = 0 ; i<5; i++){

    /* When completed I want to access the variable "i" */
    loader.addEventListener(Event.complete, completeHandler);
    loader.load(/* a url request */);
}

private function completeHandler(event:Event):void
{
     /* I want to access the passed parameter "i" so 
      it is the same as it was when the eventListener was added, 0,1,2,3 or 4 */

 }

这可能吗？我已尝试扩展Event，但我想处理 COMPLETE 事件

由于 菲尔

Answer 1

这应该可以使用Flex的动态功能构造。提出了类似的问题here和here。

以下是一个例子：

参数和处理程序：

var parameters:String = "Some parameter I want to pass";

private function loadLocalData(e:Event, parameter:String):void
{
  // voila, here's your parameter
}

private function addArguments(method:Function, additionalArguments:Array):Function 
{
  return function(event:Event):void {method.apply(null, [event].concat(additionalArguments));}
}

您的示例中的用法：

for(var i:int = 0 ; i<5; i++){

    /* When completed I want to access the variable "i" */
    loader.addEventListener(Event.complete, addArguments(completeHandler, [i]));
    loader.load(/* a url request */);
}

private function completeHandler(event:Event, id:int):void
{
     /* I want to access the passed parameter "i" so 
      it is the same as it was when the eventListener was added, 0,1,2,3 or 4 */

}

Answer 2

exacly - 附加方法addArguments（...）是最好的解决方案，我使用同样但它调用passParameters

public function passParameters(method:Function,additionalArguments:Array):Function
{return function(event:Event):void{
    method.apply(null, [event].concat(additionalArguments));}
}

这里的解释就是 - 简单而且始终有效http://sinfinity.pl/blog/2012/03/28/adding-parameters-to-event-listener-in-flex-air-as3/