I successfully implemented Game Center with Leaderboards into my app. It tests perfectly in the simulator when set to an iPhone. However, when I set the simulator to an iPad, it does not work. There is no crash, but it does not ask to authenticate the user when it should and I can't access Game Center from the button that I have set up.
Again, it works perfectly in the simulator when I test on an iPhone. I did not see any "device specific" code in the code that I used. Has anybody run into this problem? Is this simply an Xcode glitch?
I had this problem before, too. You need to basically reset the simulator. Do it like this:
1) While in the iPad simulator go to Hardware -> Home.
2) Click and hold on the app until it shakes and provides an "x" to delete it from the simulated device. Then, delete it.
3) Go to Hardware -> Erase all contents and settings. (Give Xcode a minute or two to perform this task.)
Now, things should be reset and ready to work properly. Give it a try. Good luck!