How to implement Game Center in iOS app?

Question

I am a bit confused now. I read through a lot articles that describe how to implement game center. All of them mention that I have to create an app at itunes connect first.

So do I have to submit my app to iTunes first? Why do I have to do that? Do I have to set a later release date than?

All suggestions appreciated!

Answer 1

You just have to create an App Id on the Itunes Connect. When you create an App Id you just give some meta-data (the most important is the Bundle Identifier) about your application but you don't have to submit any binaries. You submit the binary application when you want submit it on the App Store.

You must create an App Id because It'll allow you to use the game center server to do your tests.

There is a very good tutorial on Ray Wenderlich blog: How To Make A Simple Multiplayer Game with Game Center Tutorial

Answer 2

You don't need to submit your app but you do need to create an application on iTunes Connect. Basically, you register all the meta-data about your app (eg. the name) but don't actually upload a binary yet. In the app management area you setup Game Center leaderboards and achievements.

Before doing that though you need to create a unique ID for your app. You create the ID in the Provisioning area and it's referred to as the App ID there, but when you actually choose the ID in iTunes Connect it's referred to as the bundle ID.

Note that the way iOS actually connects Game Center to your app is using the bundle ID in the provisioning profile, so make sure to create a new development profile without wildcard characters to use when building your app.

And finally it's important to connect to the testing sandbox and not the "real" Game Center during development. Basically, if you aren't logged in to Game Center while playing your game then a pop-up will ask if you want to log into the testing sandbox.