From the documentation:
Returns The decoded bitmap, or null if the image could not be decode.
The bytes involved in the string “test” aren’t a valid bitmap, are they?
If you saved the text “test” in a file called foo.png
or foo.jpg
etc and tried to open it in Windows, what would you expect the result to be? It would be an error: those bytes simply aren’t a valid image in any known format.
EDIT: I don’t know anything about Android graphics, but your update certainly looks like a much more reasonable way to draw text onto a bitmap.