Downloading files in Flex using the FileReference class

OK, enough embedding examples, lets take a look at downloading files using Flash Player’s FileReference class (flash.net.FileReference). This example demonstrates a basic usage of the FileReference class within Flex, allowing users to download a file from the server. This example also shows how you can use data tips in the DataGrid control by setting the data grid column’s <code>showDataTips</code> property to <code>true</code> and specifying a value for the <code>dataTipField</code> column.

Full code after the jump.

The following example downloads a ZIP file when the user presses the Button control. You can mouse over the items in the DataGrid control’s “Type” column to see additional event information

&lt;?xml version="1.0" encoding="utf-8"?&gt;

&lt;!-- http://blog.flexexamples.com/2007/07/28/downloading-files-in-flex-using-the-filereference-class/ --&gt;

&lt;mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

        layout="vertical"

        verticalAlign="middle"

        backgroundColor="white"

        creationComplete="init();"&gt;   

    &lt;mx:Script&gt;

        &lt;![CDATA[

            import mx.controls.Alert;

            import mx.collections.ArrayCollection;

            import flash.net.FileReference;   

            [Bindable]

            [Embed('assets/disk.png')]

            private var diskIcon:Class;   

            private var arrColl:ArrayCollection;   

            /* URL of the file to download. */

            private const FILE_URL:String = "http://blog.flexexamples.com/wp-content/uploads/FileReference_download_test/bin/srcview/FileReference_download_test.zip";   

            private var fileRef:FileReference;

            private var urlReq:URLRequest;   

            private function init():void {

                /* Initialize the array collection to an empty collection. */

                arrColl = new ArrayCollection();   

                /* Set up the URL request to download the file specified by the FILE_URL variable. */

                urlReq = new URLRequest(FILE_URL);   

                /* Define file reference object and add a bunch of event listeners. */

                fileRef = new FileReference();

                fileRef.addEventListener(Event.CANCEL, doEvent);

                fileRef.addEventListener(Event.COMPLETE, doEvent);

                fileRef.addEventListener(Event.OPEN, doEvent);

                fileRef.addEventListener(Event.SELECT, doEvent);

                fileRef.addEventListener(HTTPStatusEvent.HTTP_STATUS, doEvent);

                fileRef.addEventListener(IOErrorEvent.IO_ERROR, doEvent);

                fileRef.addEventListener(ProgressEvent.PROGRESS, doEvent);

                fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR, doEvent);

            }   

            private function doEvent(evt:Event):void {

                /* Create shortcut to the FileReference object. */

                var fr:FileReference = evt.currentTarget as FileReference;   

                /* Add event order and type to the DataGrid control. */

                arrColl.addItem({data:arrColl.length+1, type:evt.type, eventString:evt.toString()});   

                try {

                    /* Update the Model. */

                    fileRefModel.creationDate = fr.creationDate;

                    fileRefModel.creator = fr.creator;

                    fileRefModel.modificationDate = fr.modificationDate;

                    fileRefModel.name = fr.name;

                    fileRefModel.size = fr.size;

                    fileRefModel.type = fr.type;

                    /* Display the Text control. */

                    txt.visible = true;

                } catch (err:*) {

                    /* uh oh, an error of sorts. */

                }

            private function downloadSourceCodeZip():void {

                /* Clear existing array collection. */

                arrColl = new ArrayCollection();

                /* Hide the Text control. */

                txt.visible = false;

                /* Begin download. */

                fileRef.download(urlReq);

            private function showAlert(item:Object):void {

                Alert.show(item.eventString, item.type);

            }

        ]]&gt;

    &lt;/mx:Script&gt;   

    &lt;mx:Model id="fileRefModel"&gt;

        &lt;file&gt;

            &lt;creationDate&gt;{""}&lt;/creationDate&gt;

            &lt;creator&gt;{""}&lt;/creator&gt;

            &lt;modificationDate&gt;{""}&lt;/modificationDate&gt;

            &lt;name&gt;{""}&lt;/name&gt;

            &lt;size&gt;{""}&lt;/size&gt;

            &lt;type&gt;{""}&lt;/type&gt;

        &lt;/file&gt;

    &lt;/mx:Model&gt;   

    &lt;mx:Button id="downloadBtn" label="Download example source code" icon="{diskIcon}" click="downloadSourceCodeZip()" toolTip="{FILE_URL}" height="40" /&gt;   

    &lt;mx:DataGrid id="debug" dataProvider="{arrColl}" width="{downloadBtn.width}" rowCount="5" rowHeight="22" itemClick="showAlert(event.currentTarget.selectedItem)"&gt;

        &lt;mx:columns&gt;

            &lt;mx:DataGridColumn dataField="data" headerText="#" width="20" /&gt;

            &lt;mx:DataGridColumn dataField="type" headerText="Type" showDataTips="true" dataTipField="eventString" /&gt;

        &lt;/mx:columns&gt;

    &lt;/mx:DataGrid&gt;   

    &lt;mx:Text id="txt" condenseWhite="true" visible="false"&gt;

        &lt;mx:text&gt;

        creationDate: {fileRefModel.creationDate}

        creator: {fileRefModel.creator}

        modificationDate: {fileRefModel.modificationDate}

        name: {fileRefModel.name}

        size: {fileRefModel.size}

        type: {fileRefModel.type}

        &lt;/mx:text&gt;

    &lt;/mx:Text&gt;   

&lt;/mx:Application&gt;

    本文轉自 OldHawk  部落格園部落格，原文連結：http://www.cnblogs.com/taobataoma/archive/2008/01/13/1036991.html，如需轉載請自行聯系原作者