如何用BlazeDS更改图片

相信大家在实际应用中肯定会碰到这样的问题：如何动态更改网元图片或者Topo背景？本文用具体实例演示了如何从本地上传图片到服务器，并设置为Topo背景。

首先介绍一下本文用到的技术：

1. FileReference
FileReference用于从本地打开文件，而且需要添加编译选项：-target-player=10.0.0。关于FileReference的用法请参考官方文档
FileReference API：

http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/FileReference.html

 

2. BlazeDS

本文用BlazeDS上传文件，后续文章也使用了BlazeDS。更多关于BlazeDS的信息请参考官方网站

BlazeDS：http://opensource.adobe.com/wiki/display/blazeds/BlazeDS

下面进入正题：
1. 选择图片，然后将图片显示出来

  
  

   
   private
   
    
   
   function
   
    selectImage():void {
 fileReference 
   
   =
   
    
   
   new
   
    FileReference();
 fileReference.addEventListener(Event.SELECT, 
   
   function
   
   (e:Event):void {
 fileReference.load();
 });
 fileReference.addEventListener(Event.COMPLETE, 
   
   function
   
   (e:Event):void {
 var loader:Loader 
   
   =
   
    
   
   new
   
    Loader();
 loader.contentLoaderInfo.addEventListener(Event.COMPLETE, 
   
   function
   
   (event:Event):void {
 image.source 
   
   =
   
    event.target.content;
 uploadButton.enabled 
   
   =
   
    
   
   true
   
   ;
 });
 loader.loadBytes(fileReference.data);
 });
 fileReference.browse([
   
   new
   
    FileFilter(
   
   "
   
   Image Files
   
   "
   
   , 
   
   "
   
   *.jpg;*.jpeg;*.gif;*.png;*.JPG;*.JPEG;*.GIF;*.PNG
   
   "
   
   )]);
}
  
  

 

2. 上传图片，并且在上传结束后，设置成Topo背景

 

  
  

   
    1 
   
   private
   
    
   
   function
   
    uploadImage():void {

   
    2 
   
    RemoteObjectUtil.invoke(
   
   "
   
   UploadImage
   
   "
   
   , 
   
   "
   
   uploadFile
   
   "
   
   , handleUploadSuccess, fileReference.name, fileReference.data);

   
    3 
   
   }

   
    4 
   
   

   
    5 
   
    
   
   private
   
    
   
   function
   
    handleUploadSuccess(result:
   
   Object
   
   ):void {

   
    6 
   
    
   
   if
   
   (result 
   
   as
   
    
   
   Boolean
   
    
   
   &&
   
    callBackFunction !
   
   =
   
    
   
   null
   
   ){

   
    7 
   
    callBackFunction(fileReference.name);

   
    8 
   
    PopUpManager.removePopUp(this);

   
    9 
   
    }
   
   else
   
   {

   
   10 
   
    Alert.show(
   
   "
   
   Upload Image failed.
   
   "
   
   );

   
   11 
   
    }

   
   12 
   
   };
  
  

 

  
  

   
    1 
   
   uploadImage.callBackFunction 
   
   =
   
    
   
   function
   
   (name:
   
   String
   
   ):void {

   
    2 
   
    var style:IStyle;

   
    3 
   
    
   
   if
   
   (network.currentSubNetwork 
   
   ==
   
    
   
   null
   
   ){

   
    4 
   
    style 
   
   =
   
    box;

   
    5 
   
    }
   
   else
   
   {

   
    6 
   
    style 
   
   =
   
    network.currentSubNetwork;

   
    7 
   
    }

   
    8 
   
    style.setStyle(Styles.BACKGROUND_TYPE, Consts.BACKGROUND_TYPE_IMAGE);

   
    9 
   
    style.setStyle(Styles.BACKGROUND_IMAGE, name);

   
   10 
   
   };
  
  

3. 调用后台方法的代码如下：

 

  
  

   
    1 
   
   public
   
    static 
   
   function
   
    invoke(destination:
   
   String
   
   , method:
   
   String
   
   , callBack:
   
   Function
   
   , ... parameters:
   
   Array
   
   ):void {

   
    2 
   
    var remoteObject:RemoteObject 
   
   =
   
    
   
   new
   
    RemoteObject(destination);

   
    3 
   
    remoteObject.addEventListener(FaultEvent.FAULT, 
   
   function
   
   (e:FaultEvent):void {

   
    4 
   
    Alert.show(e.toString());

   
    5 
   
    });

   
    6 
   
    remoteObject.addEventListener(ResultEvent.RESULT, 
   
   function
   
   (e:ResultEvent):void {

   
    7 
   
    
   
   if
   
   (callBack !
   
   =
   
    
   
   null
   
   ){

   
    8 
   
    callBack(e.result);

   
    9 
   
    }

   
   10 
   
    });

   
   11 
   
    remoteObject.getOperation(method).send.apply(
   
   null
   
   , parameters);

   
   12 
   
   }
  
  

4. 后台保存图片的代码如下，将PATH更改为Web工程部署后的目录：

 

  
  

   
    1 
   
   public
   
    class UploadImage {

   
    2 
   
    
   
   private
   
    final static 
   
   String
   
    PATH 
   
   =
   
    
   
   "
   
   F:/ws/java/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/BlazedsDemo/
   
   "
   
   ;

   
    3 
   
   

   
    4 
   
    
   
   public
   
    
   
   boolean
   
    uploadFile(
   
   String
   
    fileName, 
   
   byte
   
   [] content) throws Exception {

   
    5 
   
    
   
   if
   
    (content 
   
   ==
   
    
   
   null
   
    || content.length 
   
   ==
   
    
   
   0
   
   

   
    6 
   
    || fileName 
   
   ==
   
    
   
   null
   
    || fileName.length() 
   
   ==
   
    
   
   0
   
   ){

   
    7 
   
    return 
   
   false
   
   ;

   
    8 
   
    }

   
    9 
   
    File file 
   
   =
   
    
   
   new
   
    File(PATH 
   
   +
   
    fileName);

   
   10 
   
    FileOutputStream stream 
   
   =
   
    
   
   new
   
    FileOutputStream(file);

   
   11 
   
    stream.write(content);

   
   12 
   
    stream.close();

   
   13 
   
    return 
   
   true
   
   ;

   
   14 
   
    }

   
   15 
   
   }
  
  

如需源代码可留言