Flex4打印效能的实现

Flex4打印功能的实现

在学习Flex的过程中，你可能会遇到Flex4打印功能的问题，这里和大家分享一下，Flex4打印功能和Silverlight4打印功能步骤很相似，但是实现不同，Flex4的打印功能不是事件驱动，基本步骤如下文介绍。

Flex4打印功能

Flex4打印功能和Silverlight4打印功能步骤很相似，但是实现不同，Flex4的打印功能不是事件驱动，基本步骤如下：

步骤1：建立FlexPrintJob对象，可以把该对象看作Silverlight的PrintDocument;

步骤2：使用一个布尔变量控制要打印的图片格式，例如是打印矢量图还是打印位图;

步骤3：调用FlexPrintJob中的Start()方法，这时会弹出提示窗口，询问是否开始打印，选择确定，将开始打印;

步骤4：建立一个打印对象，并添加这个打印对象到现实列表中;

步骤5：使用FlexPrintJob中的addObject()添加对象到打印页面中;

步骤6：调用FlexPrintJob中的send()方法，对添加的打印页面进行打印;

步骤7：打印后，删除已经打印的视图对象;

下面提供按钮事件代码，点击按钮后，会打印出“HelloWorld”。

protectedfunctionbutton1_clickHandler(event:MouseEvent):void ??
{ ??
varjob:FlexPrintJob=newFlexPrintJob(); ??
job.printAsBitmap=false; ??
if(job.start()){ ??
vargroup:HGroup=newHGroup(); ??
group.height=job.pageHeight; ??
group.width=job.pageWidth; ??
vartext:SimpleText=newSimpleText(); ??
text.text="Hello"; ??
text.setStyle("fontFamily","Arial"); ??
text.setStyle("fontSize",12); ??
group.addElement(text); ??
text=newSimpleText(); ??
text.setStyle("fontFamily","Arial"); ??
text.setStyle("fontSize",12); ??
text.text="World"; ??
group.addElement(text); ??
addElement(group); ??
job.addObject(group,FlexPrintJobScaleType.NONE); ??
job.send(); ??
removeElement(group); ??
} ??

对比上面的两组打印代码可以看出Flex实现打印需要多设置一些参数，主要是因为：

1.在Flex打印中，需要设置打印格式，是位图模式，还是矢量图模式;

2.Flex不支持自动设置打印对象在打印页面中的宽和高;

　总结

　综上所述，我们可以看出Flex4打印功能要比Silverlight的打印功能更加健全，Flex打印功能中的打印高质量的矢量图和自动分页是两个主要亮点，而当前Silverlight4中自动分页是将要打印视图对象切割成两部分实现打印。而Silverlight4中打印功能的全编程模式也是Silverlight的亮点。从微软对Silverlight的定位方向来看，相信在不久的将来，Silverlight的打印功能会更加的强大和完善。

今天的专业实践检查时，被要求添加一个报表的打印功能，GOD！我哪知道?Flex里怎么实现打印啊，原来想的方案是用游览器自带的打印功能，以为万事OK了，没想到。。。。?
???????因为我们的项目里用的是组件开发，因为Flex中不存在一个工程下有多个页面的说法，因为主页面背景改不了，也就意味着用游览器打印只能打印当前显示的全部内容，而不仅仅是一个表格内的内容。。。。?
????????中午回来，花了二三个小时上网找了一下资料，结果，找到了单独实现打印和打印预览的代码，皇天不负有心人啊。。。。?
????????PS：以下的核心代码来自于网上，我只是将它们两个功能整合在了一起，应该会对要实现打印功能的朋友有帮助（因为打印应该都要先预览一下）。?
?
?Application:?
DataGridPrint.mxml?
<?xml?version="1.0"?>?
?
<mx:Application?xmlns:mx="http://www.adobe.com/2006/mxml"??
????height="450"??
????width="550">?
????<mx:states>?
????????<mx:State?name="printView">?
????????????<mx:RemoveChild?target="{myForm}"/>?
????????????<mx:AddChild?position="lastChild">?
????????????????<mx:Panel?width="388"?height="303"?layout="absolute">?
????????????????????<mx:Image?id="img"?x="10"?y="10"/>?
????????????????</mx:Panel>?
????????????</mx:AddChild>?
????????????<mx:AddChild?position="lastChild">?
????????????????<mx:Button?label="Back"?click="currentState="""/>?
????????????</mx:AddChild>?
????????</mx:State>?
????</mx:states>?
?
????<mx:Script>?
????????<![CDATA[?
????????????import?mx.printing.FlexPrintJob;?
????????????import?myComponent.MyPrintView;?
????????????import?mx.graphics.ImageSnapshot;?
????????????import?mx.core.UIComponent;?
????????????private?function?print(u:UIComponent):void{?
?????????????currentState="printView";?
????????????????var?bmp:BitmapData?=?ImageSnapshot.captureBitmapData(u);?
????????????????var?i:Bitmap?=?new?Bitmap(bmp);?????????????????
????????????????img.source?=?i;?
????????????????img.scaleContent?=?true;?
????????????}?
?
????????????public?function?doPrint():void?{?
????????????????//?Create?a?FlexPrintJob?instance.?
????????????????var?printJob:FlexPrintJob?=?new?FlexPrintJob();?
?????
????????????????//?Start?the?print?job.?
????????????????if(printJob.start())?{?
????????????????????//?Create?a?MyPrintView?control?as?a?child??
????????????????????//?of?the?current?view.?
????????????????????var?formPrintView:MyPrintView?=?new?MyPrintView();?
????????????????????addChild(formPrintView);????
????????????????????//?Set?the?print?control's?data?grid?data?provider?to?be??
????????????????????//?the?displayed?data?grid's?data?provider.?
????????????????????formPrintView.myDataGrid.dataProvider?=??
????????????????????????myDataGrid.dataProvider;????
????????????????????//?Add?the?SimplePrintview?control?to?the?print?job.?
????????????????????//?For?comparison,?try?setting?the??
????????????????????//?second?parameter?to?"none".?
????????????????????printJob.addObject(formPrintView);?
?????
????????????????????//?Send?the?job?to?the?printer.?
????????????????????printJob.send();?
?????
????????????????????//?Remove?the?print-specific?control?to?free?memory.?
????????????????????removeChild(formPrintView);?
????????????????}?
????????????}?
????????]]>?
????</mx:Script>?
?
?????
????<mx:Form?id="myForm">?
????????<mx:FormHeading?label="Contact?Information"/>?
????????<mx:FormItem?label="Name:?">?
????????????<mx:TextInput?id="custName"??
????????????????width="200"??
????????????????text="Samuel?Smith"?
????????????????fontWeight="bold"/>?
????????</mx:FormItem>?
????????<mx:FormItem?label="Phone:?">?
????????????<mx:TextInput?id="custPhone"??
????????????????width="200"??
????????????????text="617-555-1212"?
????????????????fontWeight="bold"/>?
????????</mx:FormItem>?
????????<mx:FormItem?label="Email:?">?
????????????<mx:TextInput?id="custEmail"??
????????????????width="200"??
????????????????text="sam@sam.com"?
????????????????fontWeight="bold"/>?
????????</mx:FormItem>?
?
????????<mx:FormHeading?label="Product?Information"/>?
????????<mx:DataGrid?id="myDataGrid"?width="300">?
????????????<mx:dataProvider>?
????????????????<mx:Object?Product="Flash"?Code="1000"/>?
????????????????<mx:Object?Product="Flex"?Code="2000"/>?
????????????????<mx:Object?Product="ColdFusion"?Code="3000"/>?
????????????????<mx:Object?Product="JRun"?Code="4000"/>?
????????????</mx:dataProvider>?
????????</mx:DataGrid>?
????????<mx:Button?label="PrintView"?click="print(myDataGrid)"/>?
????????<mx:FormItem?label="Label">?
????????</mx:FormItem>?
????????<mx:Button?id="myButton"??
????????????label="Print"??
????????????click="doPrint();"/>?
????</mx:Form>?
</mx:Application>?
?
Component:?
MyPrintView.?mxml（这是一个组件）?
<?xml?version="1.0"?>?
?
<mx:VBox?xmlns:mx="http://www.adobe.com/2006/mxml"??
????backgroundColor="#FFFFFF"??
????height="250"?width="450"??
????paddingTop="50"?paddingLeft="50"?paddingRight="50">?
?
?????
????<mx:PrintDataGrid?id="myDataGrid"?width="100%">?
????????<mx:columns>?
????????????<mx:DataGridColumn?dataField="Product"/>?
????????????<mx:DataGridColumn?dataField="Code"/>?
????????</mx:columns>?
????</mx:PrintDataGrid>?
</mx:VBox>

Flex4打印效能的实现

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