如何向事件监听器传送额外的参数

最新推荐文章于 2022-05-25 11:03:19 发布

iteye_3224

最新推荐文章于 2022-05-25 11:03:19 发布

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文章标签： Flex Apple 脚本

本文详细介绍了如何在FLEX文档中使用AS脚本来向事件监听器传递额外参数，通过内联函数实现灵活的数据传递方式，适用于按钮点击等场景。

如何向事件监听器传送额外的参数

问题摘要

在FLEX文档中所述的是，如果你要向监听器传送参数，那么你最好使用MXML标签，但是在这里要展示给你的是如何使用AS脚本完成。

解决摘要

使用内联函数

解释

solution is very simple, basically for following scenario :
arbitrary button called ABCButton,function ABCButtonListener needs to listen to click event and also receive extra parameter

"myPrivateSpecialObject"

object.

you do following :

private function ABCButtonListener(e:MouseEvent,specialObj:Object): void {
        Alert.show(specialObj.name);
 }


private function methodWhereyouDostuffAndRegisterListener(): void {
      var myPrivateSpecialObject:Object = {name:"Special String Ingredients for Orange"};

        ABCButton.addEventListener(MouseEvent.CLICK,function (e:MouseEvent) : void {
                  ABCButtonListener(e,myPrivateSpecialObject);
            });
}

P.S -----------------

you can use same structure to register listener for more than one button,for example :


private function methodWhereyouDostuffAndRegisterListener(): void {
      var myPrivateSpecialObject:Object = {name:"Special String Ingredients for Orange"};

        ABCButton.addEventListener(MouseEvent.CLICK,function (e:MouseEvent) : void {
                  ABCButtonListener(e,myPrivateSpecialObject);
            });



       myPrivateSpecialObject = {name:"Special Ingredients for Apple"};

       OtherButtonButton.addEventListener(MouseEvent.CLICK,function (e:MouseEvent) : void {
                  ABCButtonListener(e,myPrivateSpecialObject);
       });

}

above code registers same listener for two buttons but before registering second listener , we try to modify

myPrivateSpecialObject

so, reference is changed to have different value, but if you assume now each listener received different value , its not correct, they will both received latest assigned value . overall inline function is good technique to pass any number of parameters to a listener as long as listener is ready for those parameters.