Android : How to set Canvas to Non transaparent Image?

i have a bitmap of size 400*100. Now i want to increase the bitmap size to 400*200 with empty white space on bottom. i tried the below code, but its creating transaparent space, not white space.

=== My Code ===

// oldBitMap size are 400(width) and 100(height)

Bitmap newBitmap = Bitmap.createBitmap(400, 200, oldBitMap.getConfig());

Canvas canvas = new Canvas(newBitmap);

canvas.drawColor(Color.WHITE);

canvas.drawBitmap(oldBitMap, 0, 0, null);

Help Please....