There are a couple of other skeleton projects out there, showing how GameKit is used. However, I have yet to find one that is up-to-date and shows everything with a minimum of code. You could argue that this doesn't either, as it was put together in a hurry - while the Game Center Exchanges API wasn't working properly, but it helped me - maybe it could help you too.
This Xcode project contains one view controller, Simple. It does everything: updates the UI, deals with GameKit and all interactions from the player.
This projects shows how to correctly:
- End a turn.
- Quit a game in and out-of-turn.
- Update the game without ending turn.
- Request, cancel, reply and resolve exchanges. See how to:
- Invite one player to trade with (for simplicity, this app only supports one recipient).
- Reply to an exchange or let it time out, which either way moves the
.activeexchange to.completed. - And finally how the turn holder resolves the completed exchange after receiving a notification (merges the exchange data with match data).
The app uses a string as game data. For every turn, update and exchange a new string is appended to the match data so you can see what is happening. The tail of the string is shown in the interface as Match Data.
To get game related push notifications, you will have to use two devices (not the simulator), each logged in with a different Game Center player. However, the app supports 2 and 3 player games without any modifications. Simply set the number of players in the match maker controller when creating a new game.
To get two random opponents to find each other, I usually have to create at least two games on each device. You should also end the first turn on all the games you create. Of course, to avoid all of that you can simply invite the other player(s).
If you have suggestions for improving the project, please create a pull request. Alternatively you can reach me on Twitter @johanhwb.
I hope you find this project useful.