android

 // 读取SD卡图片

if (Environment.getExternalStorageState().equals(
    Environment.MEDIA_MOUNTED)) {
   File file = Environment.getExternalStorageDirectory();
   Bitmap bitmap = BitmapFactory.decodeFile(file.getPath()+"/miq/head_1001_5.png");
  }

//Bitmap转Drawable

Bitmap bitmap = new Bitmap (...);

Drawable drawable = new BitmapDrawable(bitmap );

 

//网络下载图片保存到SD卡

Button button = (Button) this.findViewById(R.id.button);
  String downloadUrl = "http://192.168.1.7:8077/iphone4/head_1001_5.png";
      URL url;
  try {
   url = new URL(downloadUrl);
   HttpURLConnection conn = (HttpURLConnection) url.openConnection();
   conn.setConnectTimeout(5*1000);
   conn.setRequestMethod("GET");
   conn.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*");
   conn.setRequestProperty("Accept-Language", "zh-CN");
   conn.setRequestProperty("Referer", downloadUrl);
   conn.setRequestProperty("Charset", "UTF-8");
   conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)");
   conn.setRequestProperty("Connection", "Keep-Alive");
   conn.connect();
      if (conn.getResponseCode()==200) {
                int fileSize = conn.getContentLength();//根据响应获取文件大小
                if (fileSize <= 0) throw new RuntimeException("Unkown file size ");
                String filename = "head_1001_5.png";//获取文件名称
                File file = Environment.getExternalStorageDirectory();
    file = new File(file.getPath()+"/miq");
    if (!file.exists()) {
     file.mkdirs();
    }
                File saveFile = new File(file, filename);//构建保存文件
                RandomAccessFile threadfile = new RandomAccessFile(saveFile, "rwd");
                InputStream inStream = conn.getInputStream();
                byte[] buffer = new byte[1024];
                int offset = 0;
                while ((offset = inStream.read(buffer, 0, 1024)) != -1) {
                    threadfile.write(buffer, 0, offset);
                }
                threadfile.close();
                inStream.close();
      }
  } catch (MalformedURLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }