android擷取網路上的圖片

// 如果緩衝裡面有就從緩衝擷取，否則網路擷取圖片，返回Drawable對象       public static Drawable loadImageFromNetwork(Context context, String imageUrl)       {           Drawable drawable = null;           if(imageUrl == null )               return null;           String imagePath = "";           String   fileName   = "";                          // 擷取url中圖片的檔案名稱與尾碼           if(imageUrl!=null&&imageUrl.length()!=0){                fileName  = imageUrl.substring(imageUrl.lastIndexOf("/")+1);           }                      // 圖片在手機本地的存放路徑,注意：fileName為空白的情況           imagePath = context.getCacheDir() + "/" + fileName;             Log.i("test","imagePath = " + imagePath);           File file = new File(context.getCacheDir(),fileName);// 儲存檔案           Log.i("test","file.toString()=" + file.toString());           if(!file.exists()&&!file.isDirectory())           {               try {                   // 可以在這裡通過檔案名稱來判斷，是否本地有此圖片                                      FileOutputStream   fos=new   FileOutputStream( file );                   InputStream is = new URL(imageUrl).openStream();                   int   data = is.read();                    while(data!=-1){                            fos.write(data);                            data=is.read();;                    }                    fos.close();                   is.close();   //              drawable = Drawable.createFromStream(   //                      new URL(imageUrl).openStream(), file.toString() ); // (InputStream) new URL(imageUrl).getContent();                   drawable = Drawable.createFromPath(file.toString());                   Log.i("test", "file.exists()不檔案存在，網上下載:" + drawable.toString());               } catch (IOException e) {                   Log.d("test", e.getMessage());               }           }else          {               drawable = Drawable.createFromPath(file.toString());               Log.i("test", "file.exists()檔案存在，本地擷取");           }                      if (drawable == null) {               Log.d("test", "null drawable");           } else {               Log.d("test", "not null drawable");           }                      return drawable ;       }  
AsyncTask擷取url圖片
 
mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;   new DownloadImageTask().execute(IMAGE_URL) ;   private class DownloadImageTask extends AsyncTask<String, Void, Drawable>    {                      protected Drawable doInBackground(String... urls) {               return loadImageFromNetwork(urls[0]);           }             protected void onPostExecute(Drawable result) {               mImageView.setImageDrawable(result);           }   }