问如何将位图转换为android中的Drawable？

Resources resources = mContext.getResources();

Drawable drawable = resources.getDrawable(R.drawable.a);

imageview.setBackground(drawable);

Resources r = this.getContext().getResources();

Inputstream is = r.openRawResource(R.drawable.my_background_image);

BitmapDrawable  bmpDraw = new BitmapDrawable(is);

Bitmap bmp = bmpDraw.getBitmap();

Bitmap bmp=BitmapFactory.decodeResource(r, R.drawable.icon);

Bitmap newb = Bitmap.createBitmap( 300, 300, Config.ARGB_8888 ); 

InputStream is = getResources().openRawResource(R.drawable.icon);  

Bitmap mBitmap = BitmapFactory.decodeStream(is);