FlexCamp 说明 (3之第三部) : FileReference save()

 本文来自：

http://blog.everythingflex.com/2009/09/10/flexcamp-presentation-part-3-of-3-filereference-save/

 

 

在本系列帖子的第一部里，我说明了如何使用FileReference load()方法将一个文件上载到Flash Player里。在第二部，我说明了如何使用PIxel Bender过滤已上载的图像。

在这个部分，我将说明如何使用FileReference save()方法保存图像到文件系统。

 

 

 

 

点击这里运行程序 (启动View source)

下面说明它是如何运作的。我们来看下下面的代码。

 在第19行，我创建了一个FileReference实例，称为saveFileRef。

 第142行包含了一个保存按钮，在被点击时，调用capture()。

 第112行的capture()方法执行如下：创建一个BitmapData类实例传递图像组件的高度和宽度。下一步，BitmapData’s draw()方法被调用，图像组件作为目标被传递。使用第11行初始化的PNGEncoder，通过编码BitmapData创建一个byteArray。注意：你也可以使用JPEGEncoder类。图像的原有扩展然后被读取，我们可用png扩展取代之，从而避免损坏文件。最后，在第118行，我们调用FileReference save()方法，传递ByteArray 和被建议的文件名。调FileReference save()方法启动了文件系统浏览器，让用户可以覆盖被建议的文件名，并更改地址。

安全提示：FileReference类上的save()方法必须通过直接用户互动被调用（如，点击按钮）。用程序调用方法会破坏Flash Player的安全性。

<?xml version="1.0" encoding="utf-8"?><mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" backgroundColor="0xFFFFFF" applicationComplete="init();" viewSourceURL="srcview/index.html"> <mx:Script> <!--[CDATA[ import mx.controls.Alert; import mx.formatters.NumberFormatter; import mx.graphics.codec.PNGEncoder; // encoder to create file to save private var png:PNGEncoder = new PNGEncoder(); // allowed file types private var fileTypes:FileFilter = new FileFilter("Image", "*.jpg;*.jpeg;*;*.gif;*.png;*"); // FileReference classes for upload and download [Bindable] private var loadFileRef:FileReference = new FileReference(); private var saveFileRef:FileReference = new FileReference(); // filter objects [Embed("filters/pixelate.pbj", mimeType="application/octet-stream")] private var PixelateFilterClass:Class; [Embed("filters/SmartNormalMap.pbj", mimeType="application/octet-stream")] private var SmartNormalMapFilterClass:Class; [Embed("filters/twirl.pbj", mimeType="application/octet-stream")] private var TwirlFilterClass:Class; [Embed("filters/ZoomBlurFocus.pbj", mimeType="application/octet-stream")] private var ZoomBlurFocusClass:Class; // Shaders private var pixelateShader:Shader; private var smartNormalMapShader:Shader; private var twirlShader:Shader; private var zoomBlurFocusShader:Shader; // ShaderFilters private var pixelateFilter:ShaderFilter; private var smartNormalMapFilter:ShaderFilter; private var twirlFilter:ShaderFilter; private var zoomBlurFocusFilter:ShaderFilter; // format file size private var numberFormatter:NumberFormatter = new NumberFormatter(); // timers to track upload time private var startTime:Date; private var endTime:Date; // call on applicationComplete private function init():void { // add event listeners for upload loadFileRef.addEventListener(Event.SELECT, fileSelected); loadFileRef.addEventListener(ProgressEvent.PROGRESS, loadProgress); loadFileRef.addEventListener(Event.COMPLETE, loadCompleted); loadFileRef.addEventListener(IOErrorEvent.IO_ERROR, ioerror); // create new shaders and filters pixelateShader = new Shader(new PixelateFilterClass() as ByteArray); pixelateFilter = new ShaderFilter(pixelateShader); smartNormalMapShader = new Shader(new SmartNormalMapFilterClass() as ByteArray); smartNormalMapFilter = new ShaderFilter(smartNormalMapShader); twirlShader = new Shader(new TwirlFilterClass() as ByteArray); twirlFilter = new ShaderFilter(twirlShader); zoomBlurFocusShader = new Shader(new ZoomBlurFocusClass() as ByteArray); zoomBlurFocusFilter = new ShaderFilter(zoomBlurFocusShader); } // launch the file system browse dialog and filter file types private function browseAndUpload():void { log.text=""; image.source=null; removeFilters(); loadFileRef.browse([fileTypes]); } // called after a file has been selected within the file system browser private function fileSelected(evt:Event):void { log.text += "file size: " + numberFormatter.format(loadFileRef.size) +" bytes/n"; log.text += "file name: " + loadFileRef.name +"/n"; startTime = new Date(); loadFileRef.load(); } // load progress captured for progress bar private function loadProgress(evt:ProgressEvent):void { progressBar.visible = true; progressBar.setProgress( Number(evt.bytesLoaded / evt.bytesTotal), 1 ); progressBar.label = numberFormatter.format(evt.bytesLoaded) + " of " + numberFormatter.format(evt.bytesTotal) + " bytes uploaded"; } // load has completed private function loadCompleted(evt:Event):void { image.source = loadFileRef.data; progressBar.setProgress(1,1); progressBar.visible = false; endTime = new Date(); log.text += "upload time: " + (endTime.time - startTime.time) + " milliseconds"; } // load error public function ioerror(evt:IOErrorEvent):void{ Alert.show(evt.text,"Error"); } // capture image and save back to client private function capture():void{ var bitmapData:BitmapData = new BitmapData(image.width, image.height); bitmapData.draw(image); var ba:ByteArray = png.encode(bitmapData); // split off the original extension and replace with png var ext:String = loadFileRef.name.split(".").pop(); saveFileRef.save(ba,loadFileRef.name.replace(ext,"png")); } // add PixelBender filter private function addFilter(filter:ShaderFilter):void{ var filters:Array = image.filters; filters.push(filter); image.filters = filters; } // remove all filters private function removeFilters():void{ image.filters = null; } // return true when image is available private function buttonsEnabled(bytes:ByteArray):Boolean{ if(bytes.length)return true; return false; } ]]--> </mx:Script> <mx:HBox> <mx:Button label="Load file" click="browseAndUpload()"/> <mx:Button label="Save file" click="capture()" enabled="{buttonsEnabled(loadFileRef.data)}"/> <mx:Button label="Pixelate" click="addFilter(pixelateFilter)" enabled="{buttonsEnabled(loadFileRef.data)}"/> <mx:Button label="SmartNormalMap" click="addFilter(smartNormalMapFilter)" enabled="{buttonsEnabled(loadFileRef.data)}"/> <mx:Button label="Twirl" click="addFilter(twirlFilter)" enabled="{buttonsEnabled(loadFileRef.data)}"/> <mx:Button label="ZoomBlurFocus" click="addFilter(zoomBlurFocusFilter)" enabled="{buttonsEnabled(loadFileRef.data)}"/> <mx:Button label="Remove All Filters" click="removeFilters()" enabled="{buttonsEnabled(loadFileRef.data)}"/> </mx:HBox> <mx:TextArea id="log" width="700" height="60" /> <mx:ProgressBar id="progressBar" visible="false" mode="manual"/> <mx:Image id="image" maxHeight="600" maxWidth="800"/></mx:Application>