将以下内容添加到您的View或Application的属性和脚本：

<s:View xmlns:fx="http://ns.adobe.com/mxml/2009"
    ....
    ....
    backKeyPressed="view1_backKeyPressedHandler(event)">

    // Add this to your <fx:Script> area:
    protected function view1_backKeyPressedHandler(event:FlexEvent):void
    {
        event.preventDefault();
        event.stopImmediatePropagation();
    }