flex datagrid的分页显示

1、源码主要如下：

<?xml version="1.0" encoding="utf-8"?>
<s:Group xmlns:fx="http://ns.adobe.com/mxml/2009"
   xmlns:s="library://ns.adobe.com/flex/spark"
   xmlns:mx="library://ns.adobe.com/flex/mx"
   width="100%" height="100%" creationComplete="init();">

<s:layout>
   <s:HorizontalLayout/>
</s:layout>
<fx:Declarations>
   
</fx:Declarations>

<fx:Script>
   <![CDATA[
    import com.surekam.WHJYFW.MC101000001.MC201000001.MC301000404.VO.CacheVO;

    import mx.collections.ArrayCollection;
    import mx.controls.Alert;
    import mx.controls.DataGrid;
    import mx.controls.Text;
    import spark.components.CheckBox;

    private var _currPage:int = 0;//当前页数
    private var _numPerPage:int = 10;//每页显示的页数
    private var _totalPage:int = 0;//数据源最大的页数
    private var _totalRecords:int = 0;//数据源的数量
    private var _dataProvider:Array = null;//控件的数据源
    private var currDS:ArrayCollection = null;//当前的数据集合
    private var scanPage:Array = new Array();//浏览过的页数
    private var _targetUI:Object = null;//使用数据源的控件
    private var _cacheMAX:int = 4;//缓存的页面的数目
    private var _callBackFun:Function = null;//回调函数

    [Bindable]
    private var dropSource:ArrayCollection ;
    /*
    初始化页面完毕
    */
    private function init():void{
     this.addEventListener(KeyboardEvent.KEY_UP,handlerEnter);

     dropSource = new ArrayCollection([{label:10},{label:20},{label:30},{label:40},{label:50}]);
     displayNumber.selectedIndex = 0;
//     Alert.show(_currPage+" ");
    }
    /*
    处理键盘事件
    */
    private function handlerEnter(event:KeyboardEvent):void{
     if(13 == event.keyCode){
      gotoIndex();
     }

    }
    /*
    如果改变了显示数量的话，重新加载数据源，同时也要更新缓冲的数据源
    */
    private function changeHandler(event:Event):void{
     var amount:int = parseInt((event.target as ComboBox).selectedItem.label);
     numPerPag = amount;
     /*
     重新计算分页的结果
     */
     var mod:int = _totalRecords % getNumPerPag;
     var divid:int = _totalRecords / getNumPerPag;
     totalPage = mod>0?divid+1:divid;

     cleanCache();
//     if(_currPage > totalPage){
//
//     }
     currPage =1;
    }

    /*
    清除缓冲的数据源
    */
    private function cleanCache():void{
     while(scanPage.pop()!=null){

     }
    }
    /*
    设置数据源的目标
    */
    public function set TargetUI(object:Object):void{
     this._targetUI = object;
    }
    /*
    当前页数
    */
    public function set currPage(page:int):void{
     this._currPage = page;
     this.btnNext.enabled = true;
     if(page<=1){
      this.btnPrevious.enabled = false;
     }else{
      this.btnPrevious.enabled = true;
     }

     if(page>=_totalPage){
      this.btnNext.enabled =false;
     }

     btnGo.enabled = true;
     displayData();
     displayInfo();
    }
    /*

    */
    private function displayInfo():void{
     this.txtPageIndex.text = _currPage.toString();
     lblInfo.text = "第"+_currPage+"页/共"+_totalPage+"页";
    }
    /*
    最大的页数
    */

    public function set totalPage(page:int):void{
     this._totalPage = page;
    }
    /*
    每页最大显示数量
    */
    public function set numPerPag(num:int):void{
     this._numPerPage = num;
     //(_targetUI as DataGrid).rowCount = num;
    }
    /*
    每页的数量
    */
    public function get getNumPerPag():int{
     return this._numPerPage;
    }
    /*

    */
    public function set totalRecords(record:int):void{
     this._totalRecords = record;
    }

    /*
    缓存的最大的数量
    */
    public function set cacheMAX(max:int):void{
     if(max<4){
      return ;
     }else{
      _cacheMAX = max;
     }
    }

    /*
    回调函数
    */
    public function set callBackFun(callBack:Function):void{
     this._callBackFun = callBack;
    }
    /*
    控件的数据源
    */
    public function set dataProvider(data:Array):void{
     this._dataProvider = data;
    }


    private function goto(num:int):void{
     if(-1 == num){
      currPage = _currPage-1;
     }else if(1 == num){
      currPage = _currPage+1;
     }

    }

    private function gotoIndex():void{
     var index:int = parseInt(txtPageIndex.text);
     if(index>=1 && index <= _totalPage){
      currPage = index;

     }else{
      //抛出错误
      throw new Error("输入不正确");
     }
    }
    /*
    更新缓冲区的数据源
    */
    private function refreshData(data:Array):void{

     var cacheVO:CacheVO = new CacheVO(_currPage,data);
     if(scanPage.length < _cacheMAX){
      scanPage.push(cacheVO);
     }else{
      var temp:Array = scanPage.reverse();
      temp.pop();
      temp.push(cacheVO);
      temp.reverse();
      scanPage = temp;
     }
    }
    /*
    查找哪页的数据是否在缓冲区中
    */
    private function findCache(page:int):CacheVO{
     var len:int = scanPage.length;
     var cache:CacheVO = null;
     for(var i:int =0;i<len;i++){
      cache = scanPage.pop();
      if(page == cache.pageSeq){
       return cache;
      }
     }
     return null;
    }

    public function displayData():void{
     if(this._dataProvider == null){
      throw new Error("数据源没设定");
     }

//     else{
//      var sourceVO:CacheVO = findCache(_currPage);
//      if(null == sourceVO){
//       //调用回调函数调用服务(起始序列，结束序列)
//       _callBackFun((_currPage-1)*_numPerPage, _currPage*_numPerPage);
//       refreshData(_dataProvider);
//       (_targetUI as DataGrid).dataProvider = _dataProvider;
//      }else{
//       //更新datagrid的数据源
//       (_targetUI as DataGrid).dataProvider = sourceVO.datasource;
//      }
//
//     }
    }
   ]]>
</fx:Script>

<mx:Button label="上一页" id="btnPrevious" click="goto(-1);" enabled="false" width="54"/>
<mx:Button label="下一页" id="btnNext" click="goto(1);" enabled="false" width="54"/>
<mx:Label text="转到"/>
<mx:TextInput width="48" id="txtPageIndex" restrict="0-9" text=""/>
<mx:Label text="页"/>
<mx:Button label="确定" id="btnGo" width="54" click="gotoIndex();" enabled="false"/>
<mx:Label text="显示数量："/>
<s:ComboBox id="displayNumber" dataProvider="{dropSource}"
     change="changeHandler(event);"
     selectedIndex="1" width="49"/>
<mx:Label id="lblInfo" text=""/>
</s:Group>