GKLocalPlayer Fetch Saved Games With Completion Handler Returns 0 Games on Installation

Problem Description

The fetchSavedGamesWithCompletionHandler method of GKLocalPlayer returns an empty array of saved games when the app is first installed. This issue persists even after reinstalling the app, and it’s not related to connectivity issues with Game Center or iCloud.

The Issue

When we call fetchSavedGamesWithCompletionHandler, the method returns an empty array of saved games. However, if we wait for a short period before calling the method again, it successfully retrieves the saved games. This behavior is inconsistent and can be frustrating for users.

Background

The fetchSavedGamesWithCompletionHandler method is used to retrieve an array of saved games from iCloud or Game Center. The method takes a completion handler as an argument, which is called when the operation is complete. If the method returns an empty array, it means that no saved games were found.

Causes of the Issue

There are several reasons why fetchSavedGamesWithCompletionHandler might return an empty array:

• The app is not properly configured to work with iCloud or Game Center.
• There are connectivity issues with iCloud or Game Center.
• The device’s storage is full, preventing the app from accessing saved games.

However, in this case, we know that there are no connectivity issues and the app is properly configured. Therefore, we need to investigate other possible causes.

Solution

Our solution involves using a retry mechanism to call fetchSavedGamesWithCompletionHandler multiple times with a short delay between each attempt. This allows us to wait for any temporary issues or conflicts that might be preventing the method from returning an empty array.

Here’s an example of how we can implement this retry mechanism:

// Call fetchSavedGamesWithCompletionHandler multiple times with a delay
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    for (int i = 0; i < 4; i++) {
        [NSThread sleepForTimeInterval:i * 3.0];
        [localPlayer fetchSavedGamesWithCompletionHandler:^(NSArray<GKSavedGame *&gt; * _Nullable savedGames, NSError * _Nullable error) {
            // Do something with the saved games
        }];
    }
});

Additional Observations

We’ve found that this issue is not limited to app installations. It can also occur when:

• Game data on iCloud is manually deleted and new data is written.
• Conflict by offline writing occurs, and data is discarded by resolveConflictingSavedGames.

In these cases, we need to wait for a short period before calling fetchSavedGamesWithCompletionHandler again.

Best Practices

To avoid this issue in the future, here are some best practices:

• Always verify that your app is properly configured to work with iCloud or Game Center.
• Implement a retry mechanism when calling fetchSavedGamesWithCompletionHandler.
• Handle errors and conflicts gracefully by using error checking and conflict resolution mechanisms.

By following these guidelines, you can ensure that your app works seamlessly with iCloud and Game Center, even in the face of temporary issues or conflicts.

Last modified on 2025-01-10