BitmapとDrawableの変換

Bitmap(どう描くか) Drawable(何を描くか)

//Resource　→　Bitmap
BitmapFactory.decodeResource(getResources(), R.drawable.image)

//Resource　→　Drawable
getResources().getDrawable(R.drawable.image)

//Drawable   →　Bitmap
((BitmapDrawable)drawable).getBitmap()

//Bitmap →Drawable
new BitmapDrawable(bitmap)