Is there any way to determine if a user has downloaded another app within my game?
For example, if i’ve already made GameA and am working on GameB… can i determine whether the user has purchased or downloaded GameA within GameB?
TradeNations somehow does this and they give you in-game rewards if you install and open their other games. I’m just curious how they do this…
I have no really clue but maybe it’s possible in combination of the gamecenter or openfeint platform. Maybe you can read out the game list to see which games the user has player.
You can do it through an online database, but not directly on the device.
Maybe the people don’t want your other games. For example, there are things in Dead Space 2 that you can only experience by purchasing Dead Space Ignition, and playing enough of it to be able to save. The games are not similar, other than in the world in which they take place. I think the first time I experienced this phenomenon was with Metroid Prime, which had a similar pairing with the highly inferior Metroid Fusion.
This kind of greed-fueled business is garbage. Make the other games good enough that people will want to buy them (or download them for free, if you have an ad-based model) for their own merits.
I personally find it ok, so long as it’s fluff. Don’t unlock bonus levels, but a new skin or cosmetic change can be neat for people that have multiple of your games (or 2 sequel and previous).
As for the how, I think the most effective method would be to use an online database with registration/facebook ids/any other identifier.
Otherwise players with smaller capacity devices might remove your game once completed and won’t receive credit for owning it, or may have it on their iTunes account but not currently on that device.
Actually since iOS 3.0 or 3.1 it has shared folders, which you can use for applications that share the same com.companyname basically.
read up on the iOS - ObjC documentation on how to use them.