Android fixation buttons depending on a background

Basicly I'm origination an app in that we hunt for items. So we have a
background, and there are items/stuff on it. You have to click on a
equipment that are applicable to win. The problem is, we don't know how to
make this support all devices. I'm now controlling relativelayout. Do we
have to make a opposite plans for each fortitude or is there an easier
proceed to understanding with this problem? we now place a buttons this
way:On tip of an item.Even if we use a right fortitude to way it,
infrequently there is a slight flaw to a left/right/up/down. (I do
invalidate a movement bar, though in xml it is still displayed).Extra
information:People don't seem to know what my doubt is. we basicly have a
background, let's say, of a forest. we wish a user to click on a flower
that's on my timberland background. So we place a symbol on a plcae of a
flower, make a symbol invisible. So if people click on a flower it will
give a "correct" pointer or something. But a problem is, if we make a
symbol overlie on a flower so it works for my phone for example, a symbol
won't be overlapping on a same plcae on a tablad.