我想知道是否有人知道使用Flex 4和PHP上传图像文件的最佳方式。我在网上搜索过，但大多数都使用的是Flex 2或更早的版本。我很好奇是否有任何新方法可以做到这一点。如果您知道任何好的网站或文章，请回复。我很感激帮助！
更新： 刚刚在这里找到了一个好的..
http://livedocs.adobe.com/flex/3/html/help.html?content=17_Networking_and_communications_7.html
答案 0 :(得分：5)
这将是一个很长的...
原来如此！步骤是：
MXML代码（摘录）：
<!-- Will open the browse window. -->
<s:Button id="bttSelectFile" label="Select file" click="selectFile()"/>
<!-- Will validate and start the upload process. -->
<s:Button id="bttUpload" label="Upload file" click="upload()"/>
<!-- Shows upload progress after it starts. -->
<mx:ProgressBar id="progressBar" labelPlacement="center" label="0%" width="300" height="40"
horizontalCenter="0" verticalCenter="0" alpha="0"
minimum="0" maximum="100" indeterminate="false" mode="manual"/>
ActionScript部分：
//----------------------------------------------------------
//START of Part 1: Initialization and declarations stage
//----------------------------------------------------------
import mx.controls.Alert;
//If relative doesn't work, try absolute path. Might differ between localhost home setup and production server.
private const UPLOAD_URL:String='uploadFile.php';
private var fileReference:FileReference;
//Handler for the application or component (etc) initialize event.
private function init():void
{
initializeFileReference();
}
//Instantiates fileReference variable and adds listeners.
private function initializeFileReference():void
{
fileReference=new FileReference();
fileReference.addEventListener(Event.SELECT,fileSelectHandler);//Dispatched when user selects a file from Dialog Box.
fileReference.addEventListener(Event.CANCEL,fileCancelHandler);//Dispatched when user dismisses the Dialog Box.
fileReference.addEventListener(HTTPStatusEvent.HTTP_STATUS,fileErrorHandler);//HTTP Error
fileReference.addEventListener(IOErrorEvent.IO_ERROR,fileErrorHandler);//IO Error
fileReference.addEventListener(SecurityErrorEvent.SECURITY_ERROR,fileErrorHandler);//Security Sandbox Error
fileReference.addEventListener(ProgressEvent.PROGRESS,fileProgressHandler);//Upload Progress
fileReference.addEventListener(Event.COMPLETE,fileCompleteHandler);//Dispatches when the file upload operation completes successfully
fileReference.addEventListener(DataEvent.UPLOAD_COMPLETE_DATA,fileDataCompleteHandler);//Dispatched when data has been received from the server after a successful upload.
}
//Set fileReference to NULL and removes listeners.
private function killFileReference():void
{
fileReference.removeEventListener(Event.SELECT,fileSelectHandler);
fileReference.removeEventListener(Event.CANCEL,fileCancelHandler);
fileReference.removeEventListener(HTTPStatusEvent.HTTP_STATUS,fileErrorHandler);
fileReference.removeEventListener(IOErrorEvent.IO_ERROR,fileErrorHandler);
fileReference.removeEventListener(SecurityErrorEvent.SECURITY_ERROR,fileErrorHandler);
fileReference.removeEventListener(ProgressEvent.PROGRESS,fileProgressHandler);
fileReference.removeEventListener(Event.COMPLETE,fileCompleteHandler);
fileReference.removeEventListener(DataEvent.UPLOAD_COMPLETE_DATA,fileDataCompleteHandler);
fileReference=null;
}
//----------------------------------------------------------
//END of Part 1: Initialization and declarations stage
//----------------------------------------------------------
//----------------------------------------------------------
//START of Part 2: File Selection
//----------------------------------------------------------
//Called upon pressing the select file button (bttSelectFile click handler).
private function selectFile():void
{
//Try to open the browse window.
try
{
//I disable the browse button after it's been clicked, I will enable it later. [OPTIONAL]
bttSelectFile.enabled=false;
//Limit the files the user can select.
fileReference.browse(getTypes());
}
catch(e:Error){bttSelectFile.enabled=true;Alert.show("Cannot browse for files.","Error");}
}
private function getTypes():Array
{
//Return an array of selectable file extensions (not MIME Types).
var allTypes:Array=new Array(getImageTypeFilter());
return allTypes;
}
private function getImageTypeFilter():FileFilter
{
//Limit selection to files with the jpg or jpeg extensions.
return new FileFilter("Images(*.jpg, *.jpeg)","*.jpg;*.jpeg;");
}
//Called after file was selected.
private function fileSelectHandler(event:Event):void
{
//Re-enable the bttSelectFile button in case the user wants to select a different file. [OPTIONAL]
bttSelectFile.enabled=true;
//Change the label of the button to match the select file name. [OPTIONAL]
bttSelectFile.label=fileReference.name;
}
//Called if user dismisses the browse window (Cancel button, ESC key or Close option)
private function fileCancelHandler(event:Event):void
{
//Enable the button so he is able to re-open the browse window. [OPTIONAL]
bttSelectFile.enabled=true;
}
//----------------------------------------------------------
//END of Part 2: File Selection
//----------------------------------------------------------
//----------------------------------------------------------
//START of Part 3: File Upload
//----------------------------------------------------------
//Function to validate that a file was selected and eventually other fields in the form as well.
private function valid():Boolean
{
var result:Boolean=true;
if(fileReference==null)
{
result=false;
//I set the errorString for the button. You can give user feedback anyway you want though.
bttSelectFile.errorString='You have not selected a file.';
}
//Other validation criteria
return result;
}
//Called after the upload button (bttUpload) is pressed.
private function upload():void
{
if(valid())
{
//Disable the submit button to avoid multi-submit.
bttSubmit.enabled=false;
//Call the upload funcion.
startUpload();
}
}
//Starts the upload process.
private function startUpload():void
{
try
{
//Try to upload. myPicture will be the name of the FILE variable in PHP, e.g. $_FILE['myPicture'].
fileReference.upload(new URLRequest(UPLOAD_URL),"myPicture");
}
catch(e:Error)
{
//Zero-byte file error.
Alert.show("Zero-byte file selected.","Error");
}
}
//I hadle errors in this example with a single function.
//It's better to have a different function to handle each of the 3 possible errors.
//Security Sandbox, IOError or HTTPStatus
private function fileErrorHandler(event:Event):void
{
Alert.show("File upload failed.","Error");
//For debugging you should see the entire error dump.
Alert.show(event.toString());
}
//Set ProgressBar progress to match upload progress
private function fileProgressHandler(event:ProgressEvent):void
{
//Calculate percentage uploaded.
var percentage:uint= Math.round(event.bytesLoaded*100/event.bytesTotal);
//Set progressBar progress.
progressBar.setProgress(percentage,100);
//Update progressBar label.
progressBar.label=percentage+'%';
}
//Called when file was sucessfully copied to the server.
//Upload not over yet though, PHP still has to confirm it did its part.
private function fileCompleteHandler(event:Event):void
{
//Enable bttSelectFile. [OPTIONAL]
bttSelectFile.enabled=true;
}
//Called when the PHP upload file specified in the UPLOAD_URL constant provides an "answer".
private function fileDataCompleteHandler(event:DataEvent):void
{
//I print (or echo) a number in PHP based on what happened
//3 = file is not JPG MIME Type check
//0 = move_uploaded_file function failed
//else = return the filename. I set PHP to rename the file and if all is good, it will return the name of the newly uploaded file.
var response:String=event.data;
if(response=='3'){Alert.show("Selected file is not a JPG.","Error");}
else if(response=='0'){Alert.show("File upload failed.","Error");}
else
{
//Do whatever you want, upload process completed successfully.
//Maybe insert into database?
}
}
//----------------------------------------------------------
//END of Part 3: File Upload
//----------------------------------------------------------