Beginning iOS Game Center and Game Kit: For iPhone, iPad, and iPod touch

An Overview of Achievements in Game Center

Achievements, also known as badges in certain circles, function slightly differently in Game Center than on other platforms. As with leaderboards, achievements first need to be configured in iTunes Connect on a per-app basis. You will be creating new instances of a GKAchievement object to report progress (more on this object later). Unlike leaderboard entries, which are created when a score is reached and submitted, achievements can report incremental progress.

Another notable change from working with leaderboards (see Chapter 3 for more on leaderboards) is that you will use two different types of objects to submit and retrieve achievements. GKAchievement is used to submit new achievements or update ...