General information about saved games

Currently, the saved game API is best used for single-player games or a pass-and-play game on a single device. Only the local player is required to save the game and any device can be used to retrieve the saved game information. Turn-based games already have a saved state as the turn is passed from one player to another and real-time games require all players to be present any time the game is played and only a single player can save the game.

When implementing saved games in your app, you must keep the following information in mind:

• The player must have an iCloud account to save games

• No specific limit on the amount of data that can be saved

• Game won’t be saved if there is no room in the player’s iCloud account

• The app controls how and what data is saved

• Saved games are tied to the iCloud account, not the Game Center account

Table 5-1 shows the common properties used by a GKSavedGame object.

iCloud Requirements

Saving games using the saved game APIs requires the user to have an iCloud account. Using iCloud provides users with a way to save a game from any device that has an Internet connection. Along with providing the ability to save games from anywhere, iCloud provides users with the ability to save large data files. The size of a saved game file is limited to the amount of space in the users iCloud account. However, you should always strive to minimize the amount of data being saved. This prevents the user from running out of space and decreases the amount of time required to fetch or save a game file.

Saving a Game

Today’s games are played on multiple devices depending on where the user happens to be. Whether they are at home playing on their iMac, sitting in front of a television with their iPad, or on a bus with their iPhone, a player wants to continue playing a game from the last place they left off and not have to worry about which device they were playing on. Including the ability to save and retrieve saved games greatly increases the playability of your game.

Retrieving a saved game

Players want to continue to play games they have saved, whether they saved the game on their current device or another device. To retrieve the list of games the player has saved from a device, your app calls the fetchSavedGamesWithCompletionHandler: method to retrieve the list of games for the player. This method returns a list of GKSavedGame objects that contains the identifying information for each saved game. Before presenting the list of saved games to the player, you must ensure that none of the saved games have the same name. If more than one saved game has the same name, you must resolve the name conflict before you present the list of saved games to the player.

After you have resolved any conflicts, present the list of saved games to the player, if applicable. The player then selects the saved game file they wish to continue playing. Call the loadDataWithCompletionHandler: method to retrieve the data associated with the GKSavedGame object chosen by the player.