Flex 自定义打印控件编写

打印历来是web应用一个比较棘手的问题，幸好flex web应用是运行在flash player上的，flash player可以访问打印机，所以flex 应用可以实现比较强大的打印功能。Flex 自身提供的printjob、flexprintjob相对来说用起来不是很方便，对于有严格纸张设置、翻页等打印需求，略显功能不足，因此需要基于printjob或flexprintjob来完善flex的打印功能，及自定义打印控件。

       本控件核心为：

       1）PrintManager，打印控制核心类

    2）IPrintableDocument，打印文档设置，打印文档有3部分组成，分别是：PrintableHeader、PrintableBody、PrintableFooter。

    因此，开发人员只要设计好printabledocument,重点排版好header、body、footer，然后调用PrintManager的打印即可打印printabledocument了。

<print:PrintableDocument

        printableBody="{p_body}" printableFooter="{p_footer}" printableHeader="{p_header}">  

    <print:PrintableHeader width="100%" id="p_header" x="0" y="0" height="81" >

       <mx:Label id="pageHeader" text="Sample Accounts" styleName="printTitle" width="100%" textAlign="center"/>

       <mx:Label id="cityHeader" text="City Of Somewheretown" width="100%" textAlign="center" />

       <mx:Label id="entityHeader" text="General Accounts" width="100%" textAlign="center"/>

    </print:PrintableHeader>

    <print:PrintableBody id="p_body" width="100%" bottom = "28" x="0" top="81">

       <mx:PrintAdvancedDataGrid id="accountsDataGrid" designViewDataType="flat"

                          dataProvider="{accounts}" horizontalGridLines="false" verticalGridLines="false"

                          width="100%" height="100%" borderStyle="none" sortExpertMode="true" headerHeight="0"

                          rowHeight="30">

           <mx:columns>

              <mx:AdvancedDataGridColumn headerText="Account Number" dataField="account" textAlign="center" width="100"/>

              <mx:AdvancedDataGridColumn headerText="Control Account" dataField="control" textAlign="center" width="100"/>

              <mx:AdvancedDataGridColumn headerText="Description" dataField="description" width="300"/>

           </mx:columns>

       </mx:PrintAdvancedDataGrid>

    </print:PrintableBody>

    <print:PrintableFooter id="p_footer" width="100%" height="28" bottom="0" left="0" printType="perpage">

       <mx:Label text="Prepared by: Authorname" width="33%" textAlign="center"/>

       <mx:Label text="Page {pageNumber} of {pageCount}" width="34%" textAlign="right"/>     

       <mx:Label id="pageFooter" text="Sample Accounts" width="33%"/>

    </print:PrintableFooter>

</print:PrintableDocument>

       附上控件核心类的相关代码。

       1、PrintManager

    public class PrintManager

    {

       public function PrintManager()

       {

       }

      

       public function print(document:IPrintableDocument, parent:UIComponent = null):Boolean

       {

           var printJob:PrintJob = new PrintJob();

          

           if (parent != null)

             parent.addChild(document.displayObject());

           

           var printed:Boolean = printInternal(document, printJob);          

           

            if (parent != null)

              parent.removeChild(document.displayObject());

           

            return printed;

        }

       

        private functionunscaleDocument(document:IPrintableDocument):void

        {

            document.scaleX = 1.0;

            document.scaleY = 1.0;

            document.validateNow();

        }

       

       /**

        * adjust print orientation

        * scale the printdocument

        */

        private functionrotateDocumentForPaperOrientation(document:IPrintableDocument, printJob:PrintJob):void

        {

           document.x = 0;

           document.y = 0;

          

           var scaleFactor:Number = 1.0;

           //

           document.scaleX = scaleFactor;

           document.scaleY = scaleFactor;

           document.validateNow();

        }

       

       private function printPage(document:IPrintableDocument, printJob:PrintJob):void

       {

           var Number = document.desiredWidth;

           var height:Number = document.desiredHeight;

           var page:Sprite = Sprite(document);

           var printableArea:Rectangle = new Rectangle(0, 0, width, height);

           printJob.addPage(page, printableArea);

       }

      

        public function printInternal(document:IPrintableDocument, printJob:PrintJob):Boolean

        {

           //start printer

            if (!printJob.start()) {

              return false;

            }

            document.moveToFirstPage();

           unscaleDocument(document);

           //adjust paper orientation

           rotateDocumentForPaperOrientation(document, printJob);

          

           //add first print page

         printPage(document, printJob);

            while(document.validNextPage)

           {

              document.nextPage();

              printPage(document, printJob);

           }

          

            printJob.send();

            return true;

        }

    }

       2、IPrintableDocument

    public interface IPrintableDocument extends IUIComponent, IEventDispatcher

    {

       function nextPage():void;

       function get validNextPage():Boolean;

       function previousPage():void;

       function moveToFirstPage():void;

       function validateNow():void;

       function displayObject():DisplayObject;

       function get desiredWidth():Number;

       function get desiredHeight():Number;

       function get printableFooter():PrintableFooter;

       function get printableHeader():PrintableHeader;

       function get printableBody():PrintableBody;

       function set printableBody(body:PrintableBody):void;

       function set printableHeader(header:PrintableHeader):void;

       function set printableFooter(footer:PrintableFooter):void;

       function get totalPageCount():Number;

       function get currentPageNumber():Number;

    }

       3、PrintableDocument

    public class PrintableDocument extends VGroup implementsIPrintableDocument

    {

       [Bindable]public var pageNumber:Number = 1;

       [Bindable]public var pageCount:Number = 1;

       private var _body:PrintableBody;

       private var _header:PrintableHeader;

       private var _footer:PrintableFooter;

       private var _desiredWidth:Number = 595;

       private var _desiredHeight:Number = 842;

       //

       public function PrintableDocument(){

           this.gap = 0;

       }

      

       public function get desiredWidth():Number

       {

           return _desiredWidth;    //21cm, A4,1cm=28.346px

       }

      

       public function set desiredWidth(value:Number):void{

           _desiredWidth = value;

       }

      

       public function set desiredHeight(value:Number):void{

           _desiredHeight = value;

       }

      

       public function get desiredHeight():Number

       {

           return _desiredHeight;   //29.7cm, A4

       }

      

       public function get totalPageCount():Number{

           return pageCount;

       }

      

       public function get currentPageNumber():Number{

           return pageNumber;

       }

      

       public function displayObject():DisplayObject

       {

           return this;

       }

      

       public function get validNextPage():Boolean

       {

           return printableBody.printGrid.validNextPage;

       }

      

       public function nextPage():void

       {

           printableBody.printGrid.nextPage();

           pageNumber++;

          

           if(pageNumber == 2)

           {

              removeHeaderFromLayout();

           }

           if(!validNextPage){

              includeFooterInLayout();

           }

           validateNow();

       }

      

       /**

        * move to previous page.

        */

       public function previousPage():void

       {

           printableBody.printGrid.previousPage();

           pageNumber--;

          

           if (pageNumber == 1)

           {

              includeHeaderInLayout();

           }

           removeFooterFromLayout();

           validateNow();

//         dispatchEvent(new Event("validPagesChanged"));

       }

      

       /**

        * move to first page.

        */

       public function moveToFirstPage():void

       {

           pageNumber = 1;

           printableBody.printGrid.moveToFirstPage();

           includeHeaderInLayout();

           removeFooterFromLayout();

           validateNow();

       }

      

       /**

        * calcutate page count.

        */

       public function calculatePageCount():void

       {

           var count:Number=1;

           moveToFirstPage();

           while(printableBody.printGrid.validNextPage)

           {

              count++;

              if(count == 2)

              {

                  removeHeaderFromLayout();

              }

              printableBody.printGrid.nextPage();

              validateNow();

           }

           pageCount = count;

           moveToFirstPage();

       }

             

       private function includeHeaderInLayout():void

       {

           printableHeader.includeInLayout = true;

           printableHeader.visible = true;

       }

      

       private function removeHeaderFromLayout():void

       {

          if(printableHeader.printType==PrintableHeader.PRINTTYPE_FIRSTPAGE){

              printableHeader.includeInLayout = false;

              printableHeader.visible = false;

           }

       }

      

       private function includeFooterInLayout():void{

           printableFooter.includeInLayout = true;

           printableFooter.visible = true;

       }

      

       private function removeFooterFromLayout():void{

          if(printableFooter.printType==PrintableFooter.PRINTTYPE_LASTPAGE && validNextPage){

              printableFooter.includeInLayout = false;

              printableFooter.visible = false;

           }

       }

             

       public function get printableBody():PrintableBody{

           return _body;

       }

      

       public function set printableBody(body:PrintableBody):void{

           this._body = body;

       }

      

       public function get printableFooter():PrintableFooter{

           return _footer;

       }

      

       public function setprintableFooter(footer:PrintableFooter):void{

           this._footer = footer;

       }

      

       public function get printableHeader():PrintableHeader{

           return this._header;

       }

      

       public function setprintableHeader(header:PrintableHeader):void{

           this._header = header;

       }

    }

4、PrintableHeader、PrintableBody、PrintableFooter代码

<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="400" height="300">

    <fx:Declarations>

       <!-- 将非可视元素（例如服务、值对象）放在此处 -->

    </fx:Declarations>

    <s:Rect width="100%" height="100%">

       <s:fill><s:SolidColor color="0xFF4500" /></s:fill>

    </s:Rect>

    <fx:Script>

       <![CDATA[

           /**

            *[firstpage,perpage]<br/>

            *firstpage,header区域只在第一页打印<br/>

            *perpage,header区域每页都会打印

            */

           public var printType:String = "firstpage";

           public static const PRINTTYPE_FIRSTPAGE:String ="firstpage";

           public static const PRINTTYPE_PERPAGE:String = "perpage";

       ]]>

    </fx:Script>

</s:Group>

Body：

<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="400" height="500">

    <fx:Declarations>

       <!-- 将非可视元素（例如服务、值对象）放在此处 -->

    </fx:Declarations>

 

    <fx:Script>

       <![CDATA[

           import mx.printing.PrintAdvancedDataGrid;

           public var printGrid:PrintAdvancedDataGrid;

       ]]>

    </fx:Script>

</s:Group>

Footer:

<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="400" height="300">

    <fx:Declarations>

       <!-- 将非可视元素（例如服务、值对象）放在此处 -->

    </fx:Declarations>

    <s:Rect width="100%" height="100%">

       <s:fill><s:SolidColor color="0xFF00ff" /></s:fill>

    </s:Rect>

    <fx:Script>

       <![CDATA[

           /**

            *[lastpage,perpage]<br/>

            *lastpage,footer区域只在最后一页打印<br/>

            *perpage,footer区域每页都会打印

            */

           public var printType:String = "lastpage";

           public static const PRINTTYPE_LASTPAGE:String = "lastpage";

           public static const PRINTTYPE_PERPAGE:String = "perpage";

       ]]>

    </fx:Script>

</s:Group>