Did you need to load a stretchy nine-patch drawable from your assets
or the network, rather than directly via a resource? If so, you begin
to realize that the foo.9.png file in your source is actually
different from what's compiled into your apk, and you have to do
something similar before you can use the goodness of NinePatchDrawables.
This aapt command converts a single input.9.png into
a version that can be loaded as a NinePatchDrawable
aapt singleCrunch -v -i input.9.png -o compiled_input.9.png
To load it within your code, simply use BitmapFactory
to create a Bitmap from compiled_input.9.png, and then use
new NinePatch(mybitmap, mybitmap.getNinePatchChunk(), null)
to create a NinePatch, and then use that within a suitable NinePatchDrawable constructor to arrive at a nice, stretchable Drawable.