使用弹出子窗口以及子窗口数据回传(转)

简单做了个带登陆子窗口的app做试验。
子窗口的使用参照help文档中的相关主题使用PopUpManager.createPopUp(...)方法实现，不过参考网上一些朋友的blog中所说的“使用parent访问父对象的属性来回传数据”的方法似乎有点出入，怀疑是版本不同的原因，经过尝试，最终使用以下代码获取父窗口：
var obj:Default = Default(this.parentApplication); //其中Default是父窗口的文件名。

最终的代码如下，首先是登陆子窗口LoginWindow.mxml：

<?xml version="1.0" encoding="utf-8"?>
<mx:TitleWindow xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" width="100%"
     height="100%" creationComplete="doInit();" title="Login Window">
    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.managers.FocusManager;
            import mx.core.Application;
            import mx.managers.PopUpManager;
            
            private function doInit():void 
            {
                PopUpManager.centerPopUp(this);
            }
            
            private function processLogin():void 
            {
                this.lb1.text = "";
                if(this.username.text=="")
                {
                    this.lb1.text = "用户名不能为空。";
                    return;
                }
                if(this.password.text==this.username.text+"1")
                {
                    try
                    {
                        var obj:Default = Default(this.parentApplication);
                        obj.ShowUser(this.username.text);
                    }
                    catch(e:Error)
                    {
                        Alert.show(e.message, 'Error');
                    }
                    PopUpManager.removePopUp(this);
                }
                else
                {
                    this.password.text = "";
                    this.password.focusEnabled = true;
                    this.lb1.text = "用户名或密码错误。";
                }
            }
        ]]>
    </mx:Script>
    <mx:Form>
        <mx:FormItem label="User Name">
            <mx:TextInput id="username" width="100%"/>
        </mx:FormItem> 
        <mx:FormItem label="Password">
            <mx:TextInput id="password" displayAsPassword="true" width="100%"/>
        </mx:FormItem> 
    </mx:Form>
    <mx:HBox> 
        <mx:Button click="processLogin();" label="OK"/> 
        <mx:Button click="this.username.text=''; this.password.text='';" label="Reset"/> 
        <mx:Label id="lb1" text="" color="red" />
    </mx:HBox> 
</mx:TitleWindow>

在主窗口Default.xml中添加以下内容：

            //……

            private function OnInit():void
            {
                showLogin();
            }

            private function showLogin():void 
            {
                var win:TitleWindow = TitleWindow(
                PopUpManager.createPopUp(this, Components.LoginWindow, true));
                win.setStyle("borderAlpha", 0.9);
            }

            public function ShowUser(un:String):void
            {
                this.lblUser.text = "早上好，"+un;
            }

            //……

            <mx:Label id="lblUser" text="早上好" paddingLeft="20"/>

            //……