I'm writing an android app and can't figure out how to display a ramp (could be a bump, like a speed bump, but preferably a ramp) from a top down 2d vie
I would consider just skewing the ramp 1 or 2 degrees and giving it a little dropshadow. It may not be real, but it gives the illusion of depth.
Key is that your global illumination stays the same. This means that you let shadows cast the same way and that your light source is directed the same way. Otherwise it feels out of place
Here is a simple example. The rest is up to you :)
Edit: I added a trapezoid version to show you how that would look. Great tip from Abhranil Das, I overlooked the perspective in that part. It's just a slight enhgancement but it works very well!
I'm no graphic designer, but have you thought about using gradients? For example:
This could be your standard ramp.
This could be your speed bump.
Obviously, they'd have to look a little nicer than this. :P
Roberto's image is good enough, but what I feel would add to the effect is if you use trapezoids instead of rectangles, with the wider end signifying the end which is 'up'. I guess that would complete the effect satisfactorily.