Flex 3 体验:AdvancedDataGrid的使用(第一部分)

今天我们要说的是官方文档中用了整章介绍的AdvancedDataGrid，AdvancedDataGrid是DataGrid的高级版本，Flex 3 SDK并不包含它，其和Charting Enhancements一起构成了Flex Data Visualization package，TNND，也就是说这是收费组件，ADOBE的生财机器。所以官方提供的SDK中并没有这个组件，不过FlexBuilder 3 Beta1内置的SDK包含了Flex Data Visualization package，这个我已经将FlexBuilder 3 Beta1内置的SDK剥离出来了，需要的朋友可以从这里下载。

相对DataGrid组件，AdvancedDataGrid主要有以下几个高级之处：

多列排序：按住Control键在点击某一列的表头来实现多列排序。
自定义行和列样式：通过设置行和列的styleFunction指向一个函数来样式化行列
显示分层数据：在组件的第一列显示一个可缩放的导航数来控制表格行的显示。
创建多列分组：将多列汇聚到同一列表头下。
使用单元渲染器（renderers）：跨越多栏使用同一渲染器或者一列使用多个渲染器。
多列排序

缺省的情况下，AdvancedDataGrid是按数据添加到它的DataProvider的顺序显示数据，和DataGrid组件一样，AdvancedDataGrid也允许您在数据显示后对数据进行排序。不同的是DataGrid只能基于单列排序，而 AdvancedDataGrid支持基于多列的排序。

以下是多列排序的示例：
程序代码
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

    <mx:Script>
      <![CDATA[
         import mx.collections.ArrayCollection;
                 
         [Bindable]
         private var dpADG:ArrayCollection = new ArrayCollection([
           {Artist:'Pavement', Album:'Slanted and Enchanted', Price:12.99},
           {Artist:'Pavement', Album:'Brighten the Corners', Price:13.99},
           {Artist:'Saner', Album:'A Child Once', Price:14.99},
           {Artist:'Saner', Album:'Helium Wings', Price:12.99},
           {Artist:'The Doors', Album:'The Doors', Price:10.99},
           {Artist:'The Doors', Album:'Morrison Hotel', Price:12.99},
           {Artist:'Grateful Dead', Album:'American Beauty', Price:11.99},
           {Artist:'Grateful Dead', Album:'In the Dark', Price:17.99},
           {Artist:'Grateful Dead', Album:'Shakedown Street', Price:13.99},
           {Artist:'The Doors', Album:'Strange Days', Price:12.99},
           {Artist:'The Doors', Album:'The Best of the Doors', Price:10.99}
         ]);                 
      ]]>
    </mx:Script>

    <mx:AdvancedDataGrid width="100%" height="100%"
        dataProvider="{dpADG}">
        <mx:columns>
            <mx:AdvancedDataGridColumn dataField="Artist" />
            <mx:AdvancedDataGridColumn dataField="Album" />
            <mx:AdvancedDataGridColumn dataField="Price" />
        </mx:columns>
    </mx:AdvancedDataGrid>
</mx:Application>

运行实例
运行以上示例，如下进行排序：

点击AdvancedDataGrid组件的任意列表头对任意列进行排序，例如点击Artist列的列表头Artist列将升序进行排序，再次点击的话将按降序排序。
按住Control键，点击其他任意的列头，例如点击Price列头，将在保持Artist列降序排列的情况下，将Price列按升序排列。现在你可以从中发现某一艺术家最便宜的专辑。
再次点击Price列头，Price列将按降序排列
按住Control键，点击任意其他列，将其加入排序条件中。

自定义行列样式

通过使用AdvancedDataGrid组件的回调(callback)函数来自定义表格行列的样式，要控制某一行的样式，使用AdvancedDataGrid.styleFunction属性，要自定义某一列的样式，使用AdvancedDataGridColumn.styleFunction属性，AdvancedDataGrid.styleFunction指定的回调函数先执行，接着才执行AdvancedDataGridColumn.styleFunction属性指定的函数。

回调函数必须要有如下声明：
程序代码
public function myStyleFunction(data:Object,column:SuperDataGridColumn):Object

该函数返回一个包含用于表示样式设置的styleName:value对的完整对象，或者null。styleName为样式属性的名称，如Color，而value为样式属性的值，如0x00FF00。

AdvancedDataGrid会在更新显示时调用回调函数，如应用启动时该组件第一次会绘制的时候，或者在您调用invalidateList()来刷新组件所有行的显示时。

本节的示例将使用回调函数来定义AdvancedDataGrid的样式，本节中所有的示例都使用以下StyleData.as文件中的数据：
程序代码
[Bindable]
private var dpADG:ArrayCollection = new ArrayCollection([
   {Artist:'Pavement', Album:'Slanted and Enchanted', Price:12.99},
   {Artist:'Pavement', Album:'Brighten the Corners', Price:13.99},
   {Artist:'Saner', Album:'A Child Once', Price:14.99},
   {Artist:'Saner', Album:'Helium Wings', Price:12.99},
   {Artist:'The Doors', Album:'The Doors', Price:10.99},
   {Artist:'The Doors', Album:'Morrison Hotel', Price:12.99},
   {Artist:'Grateful Dead', Album:'American Beauty', Price:11.99},
   {Artist:'Grateful Dead', Album:'In the Dark', Price:17.99},
   {Artist:'Grateful Dead', Album:'Shakedown Street', Price:13.99},
   {Artist:'The Doors', Album:'Strange Days', Price:12.99},
   {Artist:'The Doors', Album:'The Best of the Doors', Price:10.99}
]);


定义行样式

以下示例使用AdvancedDataGrid.styleFunction属性指定一个回调函数来定义表格行样式。在该示例中，您可以使用Button控件来选择AdvancedDataGrid.styleFunction中的artist，然后回调函数将会红色高亮显示所有被选择的行。
程序代码
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
    <mx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
            // Include the data for the AdvancedDataGrid control.
            include "StyleData.as"
            // Artist name to highlight.
            protected var artistName:String;
            // Event handler to set the selected artist's name
            // based on the selected Button control.
            public function setArtistName(event:Event):void
            {
                artistName=Button(event.currentTarget).label;
                // Refresh row display.
                myADG.invalidateList();
            }
            // Callback function that hightlights in red
            // all rows for the selected artist.
            public function myStyleFunc(data:Object,
                col:AdvancedDataGridColumn):Object
            {
                if (data["Artist"] == artistName)
                return {color:0xFF0000};
                // Return null if the Artist name does not match.
                return null;
            }
        ]]>
    </mx:Script>
    <mx:AdvancedDataGrid id="myADG"
    width="100%" height="100%"
    dataProvider="{dpADG}"
    styleFunction="myStyleFunc">
        <mx:columns>
            <mx:AdvancedDataGridColumn dataField="Artist"/>
            <mx:AdvancedDataGridColumn dataField="Album"/>
            <mx:AdvancedDataGridColumn dataField="Price"/>
        </mx:columns>
    </mx:AdvancedDataGrid>
    <mx:HBox>
        <mx:Button label="Pavement" click="setArtistName(event);"/>
        <mx:Button label="Saner" click="setArtistName(event);"/>
        <mx:Button label="The Doors" click="setArtistName(event);"/>
    </mx:HBox>
</mx:Application>
运行实例

定义列样式

以下示例修改上节的示例来定义AdvancedDataGrid的行和列样式。在该示例中，所有价格小于$11.00的单元都将显示为绿色。
程序代码
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
    <mx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
            // Include the data for the AdvancedDataGrid control.
            include "StyleData.as"
            // Artist name to highlight.
            protected var artistName:String;
            // Event handler to set the selected artist's name
            // based on the selected Button control.
            public function setArtistName(event:Event):void
            {
                artistName=Button(event.currentTarget).label;
                // Refresh row display.
                myADG.invalidateList();
            }
            // Callback function that hightlights in red
            // all rows for the selected artist.
            public function myStyleFunc(data:Object,
                col:AdvancedDataGridColumn):Object
            {
                if (data["Artist"] == artistName)
                return {color:0xFF0000};
                // Return null if the Artist name does not match.
                return null;
            }
            // Callback function that hightlights in green
            // all entries in the Price column
            // with a value less than $11.00.
            public function myColStyleFunc(data:Object,
                col:AdvancedDataGridColumn):Object
            {
                if(data["Price"] <= 11.00)
                    return {color:0x00FF00};
                return null;
            }
        ]]>
    </mx:Script>
    <mx:AdvancedDataGrid id="myADG"
        width="100%" height="100%"
        dataProvider="{dpADG}"
        styleFunction="myStyleFunc">
        <mx:columns>
            <mx:AdvancedDataGridColumn dataField="Artist"/>
            <mx:AdvancedDataGridColumn dataField="Album"/>
            <mx:AdvancedDataGridColumn dataField="Price"
                styleFunction="myColStyleFunc"/>
        </mx:columns>
    </mx:AdvancedDataGrid>
    <mx:HBox>
        <mx:Button label="Pavement" click="setArtistName(event);"/>
        <mx:Button label="Saner" click="setArtistName(event);"/>
        <mx:Button label="The Doors" click="setArtistName(event);"/>
    </mx:HBox>
</mx:Application>
运行实例

在列中使用数据格式器（formatter）

AdvancedDataGridColumn 有一个formatter属性，通过它，您可以向列传递一个Formatter类，或者Formatter子类的实例。格式器类可以将数据转换为自定义的字符串。例如您可以使用CurrencyFormatter类在Price列值的加上美元符($)前缀。

格式器类可以和labelFunction属性或styleFunction属性设定的回调函数一起使用，如果您指定了一个回调函数，Flex在回调函数值返回后调用格式器类。

以下示例在修改自自定义行样式章节示例，在Price列增加了一个货币格式器以在价格前显示$前缀：
程序代码 程序代码
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
    <mx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
            // Include the data for the AdvancedDataGrid control.
            include "StyleData.as"
            // Artist name to highlight.
            protected var artistName:String;
            // Event handler to set the selected artist's name
            // based on the selected Button control.
            public function setArtistName(event:Event):void
            {
                artistName=Button(event.currentTarget).label;
                // Refresh row display.
                myADG.invalidateList();
            }
            // Callback function that hightlights in red
            // all rows for the selected artist.
            public function myStyleFunc(data:Object,
                col:AdvancedDataGridColumn):Object
            {
                if (data["Artist"] == artistName)
                return {color:0xFF0000};
                // Return null if the Artist name does not match.
                return null;
            }
        ]]>
    </mx:Script>
    <mx:AdvancedDataGrid id="myADG"
        width="100%" height="100%"
        dataProvider="{dpADG}"
        styleFunction="myStyleFunc">
        <mx:columns>
            <mx:AdvancedDataGridColumn dataField="Artist"/>
            <mx:AdvancedDataGridColumn dataField="Album"/>
            <mx:AdvancedDataGridColumn  width="75" dataField="Price">
                <mx:formatter>
                    <mx:CurrencyFormatter/>
                </mx:formatter>
            </mx:AdvancedDataGridColumn>
        </mx:columns>
    </mx:AdvancedDataGrid>
    <mx:HBox>
        <mx:Button label="Pavement" click="setArtistName(event);"/>
        <mx:Button label="Saner" click="setArtistName(event);"/>
        <mx:Button label="The Doors" click="setArtistName(event);"/>
    </mx:HBox>
</mx:Application>