1. Resources res = getResources();
2. Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon);

1. public byte[] Bitmap2Bytes(Bitmap bm) {
2. ByteArrayOutputStream baos = new ByteArrayOutputStream();
3. bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
4. return baos.toByteArray();
5. }

1. public Bitmap Bytes2Bimap(byte[] b) {
2. if (b.length != 0) {
3. return BitmapFactory.decodeByteArray(b, 0, b.length);
4. } else {
5. return null;
6. }
7. }

 Bitmap bm=xxx; //xxx根据你的情况获取

 BitmapDrawable bd= new BitmapDrawable(getResource(), bm);

 因为BtimapDrawable是Drawable的子类，最终直接使用bd对象即可。

     public static Drawable zoomDrawable(Drawable drawable, int w, int h)        {

         int width = drawable.getIntrinsicWidth();

         int height = drawable.getIntrinsicHeight();

         // drawable转换成bitmap

         Bitmap oldbmp = drawableToBitmap(drawable);

         // 创建操作图片用的Matrix对象

         Matrix matrix = new Matrix();

         // 计算缩放比例

         float sx = ((float) w / width);

         float sy = ((float) h / height);

         // 设置缩放比例

         matrix.postScale(sx, sy);

         // 建立新的bitmap，其内容是对原bitmap的缩放后的图

         Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,

                 matrix, true);

         return new BitmapDrawable(newbmp);

     }

 // 获取bitmap占用的字节数

 protected int sizeOf(Bitmap data) {

   if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB_MR1) {

      return data.getRowBytes() * data.getHeight();

   } else {

      return data.getByteCount();

   }

 }

  // 3.以RGB_565方式读入图片

  public Bitmap readBitMap(Context context, int resId) {

    BitmapFactory.Options opt = new BitmapFactory.Options();

    opt.inPreferredConfig = Bitmap.Config.RGB_565;

    opt.inPurgeable = true;

    opt.inInputShareable = true;

    // 获取资源图片

    InputStream is = context.getResources().openRawResource(resId);

    return BitmapFactory.decodeStream(is, null, opt);

   }

 // 4.获取ImageView和其中drawable的大小

 // 获取ImageView和其中drawable大小需在onWindowFocusChanged获取，在oncreate中返回的结果是0

  public void onWindowFocusChanged(boolean hasFocus) {

    ImageView imageView = (ImageView) findViewById(R.id.test1);

    Log.v("Testresult", "width= " + imageView.getWidth() + " height= "

           + imageView.getHeight());

    Log.v("Testresult", "drawawidth= "

         + imageView.getDrawable().getBounds().width()

         + " drawableheight= "

         + imageView.getDrawable().getBounds().height());

  }