Open the GAME CENTER address book without the address book

Just close it, it will not affect it! ! ! ! ! You only need to log in to your icloud, open the address book, and then turn on the positioning function.

? But the most important point is that when you add friends for the first time, your friend needs to send you a GC friend invitation. Then you will see an invitation prompt when you log in to the GC. There is no need to restart the device. Everything will happen after that. It can be used normally. (My device is not jailbroken), hope this helps.