Flex中在DataGrid加载数据时显示Loading...

      网络状况是互联网发展与软件发展的一个很大的瓶颈，如果哪天访问网上资源能象访问本地硬盘，或者能象访问内存那样快，那样咱们的计算机以后只需要输入输出设备以及网络设备就可以了，哈哈，这只是一个美好的愿望。

      Flex应用在Web开发上，避免不了网络问题，下面的说明如何在加载数据时显示Loading状态，刚刚接触Flex不久，欢迎拍砖。

 

      原理是这样的，首先定义了两一个ViewState,其中一个就是Loading状态，当点击按钮的时候就显示这个Loading视图，直到数据加载完之显示数据的视图。 

 

      先看效果图片：

      首先，点击了按钮之后就会由于网络问题显示一个遮罩，上面用了一个Label显示Loading...字样，当然这里可以用任何更加漂亮的东西替换，比如GIF的图片。这里的网络问题由于是在自己的机器上测试，是人为造成的，我的服务器代码是使用的JAVA，在服务器上延迟了三秒加载数据。 

      

三秒之后显示：

    

      

代码：

 

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
    <mx:states>
        <!--加载视图,可以自己制作加载画面，
        这个例子就只用了一个LABEL表示一下正在加载-->
        <!--数据加载成功后的State-->
        <mx:State name="ListState">
            <mx:AddChild relativeTo="{pl}" position="lastChild">
                <mx:Canvas id="can" width="100%" height="100%">
                    <mx:DataGrid id="dg" horizontalCenter="0" width="100%" height="100%" >
                        <mx:columns>
                            <mx:DataGridColumn headerText="Id" dataField="p_id"/>
                            <mx:DataGridColumn headerText="Title" dataField="p_title"/>
                        </mx:columns>
                    </mx:DataGrid>
                </mx:Canvas>
            </mx:AddChild>
        </mx:State>
        <!--加载状态的视图-->
        <mx:State name="LoadingState" basedOn="ListState">
            <mx:AddChild relativeTo="{can}" position="lastChild">
                <mx:Canvas id="shade" width="100%" height="100%"
                     backgroundColor="blue" backgroundAlpha="0.1">
                    <mx:Label text="Loading..." horizontalCenter="0" verticalCenter="0" fontSize="14"/>
                </mx:Canvas>
            </mx:AddChild>
        </mx:State>
    </mx:states>
    <mx:Script>
        <![CDATA[
            import mx.rpc.AsyncToken;
            public function listLoad() {
                this.currentState = "LoadingState";
                //var loadListResponder:LoadListResponder = new LoadListResponder(this, this.dg);
                //var token:AsyncToken = listLoadService.send();
                //token.addResponder(loadListResponder);
                listLoadService.send();
            }
        ]]>
    </mx:Script>
    <mx:HTTPService id="listLoadService"
                    url="http://...."
                    method="post">
                    <mx:result>
                        <![CDATA[
                            this.dg.dataProvider = listLoadService.lastResult.data.problems.problem;
                            this.currentState = "ListState";
                        ]]>
                    </mx:result>
    </mx:HTTPService>
    <mx:Panel id="pl" title="lOAding..." width="400" height="300">
        
    </mx:Panel> 
    <mx:Button x="10" y="333" label="Load Data" click="listLoad()"/>
</mx:Application>

 

 

 

参考文章：

 Show Flex Datagrid as busy while loading and reloading

 

问题:

 

I am using showbusycursor on my HTTPService so that while the datagid is loading is that the  cursor at least changes but I would like to do more like graying out the datagrid or something.  But I am not sure where to start I tried:

            <mx:DataGrid dataProvider="{repRoleUsersXLC}" width="100%" height="90%"
                                         id="AssUsersDG"
                                         updateComplete="this.enabled=true"
                                         creationComplete="this.enabled=false"/>

but it didn't do as expected it disabled the scroll bar but I hoped it would disable grid.  But I would like to do something that is really clear the data grid is loading and reloading thanks for any help.

 

回答：

 

You could use a loading state like I've shown you below, the loading text could be an animation or whatever you choose. In real use you would make this a custom component but to keep things simple I've just made it an app, and I've used a button to simulate the load but you would obviously change your events on the grid to do that instead:

<mx:DataGrid dataProvider="{repRoleUsersXLC}" width="100%" height="90%"
id="AssUsersDG"
updateComplete="currentState=null"
creationComplete="currentState='loading'"/>

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