GKGameCenterViewController always shows Challenges instead of Leaderboards - ios

Question

I'm using Apple's code to show a GKGameCenterViewController:
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
[self presentViewController:gameCenterController animated:YES completion:nil];
}
This is the text describing the code above:
Game Center UI is Displayed by Your View Controller (iOS)
The convention used by Game Kit is for one of your view controllers to present the Game Kit view controller. Your view controller acts as a delegate to the view controller it presents so that it can be informed when the player is finished looking at the presented screen. Listing 2-1 shows most common use of this pattern, which is to show the Game Center user interface. The Game Center view controller displays many different pieces of Game Center content, so most games should offer a button that brings the player to this screen, even if the game also shows Game Center content using a custom user interface.
When I use the recommended code I get to this screen (GameCenter Challenges), which is not what I want:
I have also tried this code:
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:#"gamecenter:"]];
By using that code, I get to the screen I expected to display:
Do I misunderstand something or am I doing something wrong? Shouldn't the first piece of code bring me to the main menu? Why won't it show the leaderboards?
UPDATE
I implemented viewState as suggested by phix23:
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
gameCenterController.viewState = GKGameCenterViewControllerStateLeaderboards;
[self presentViewController:gameCenterController animated:YES completion:nil];
}
But, it still displays the same Challenges screen, despite the fact that I want /try to display the Leaderboards screen.

Answer 1

The GKGameCenterViewController which is available since iOS 6 can show the leaderboards, achievements and challenges of your game center enabled application.
You can change the initial view by setting the viewState of the GKGameCenterViewController. If you don't set this property it will show the default view, which is the challenges view in your case. I guess you don't have setup any leaderboards or achievements so there is nothing to be shown.

Answer 2

Try using this code:
-(void)showGameCentersDefaultPage {
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
gameCenterController.viewState = GKGameCenterViewControllerStateDefault;
[self presentViewController:gameCenterController animated:YES completion:nil];
}
}
If you want to begin with a specific type of GameCenter Leaderboard you can call the following method with your leaderboardID
- (void)showLeaderboard:(NSString*)leaderboardID {
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
//The next three lines are the lines of interest...
gameCenterController.viewState = GKGameCenterViewControllerStateDefault;
gameCenterController.leaderboardTimeScope = GKLeaderboardTimeScopeToday;
gameCenterController.leaderboardCategory = leaderboardID;
[self presentViewController:gameCenterController animated:YES completion:nil];
}
}

Answer 3

For iOS 7.0, I use the following:
Display Leaderboard:
- (void)displayLeaderboard:(UIViewController *)viewController
{
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
gameCenterController.viewState = GKGameCenterViewControllerStateLeaderboards;
[viewController presentViewController:gameCenterController animated:YES completion:nil];
}
}
Display Achievements:
- (void)displayAchievements:(UIViewController *)viewController
{
GKGameCenterViewController *gameCenterController = [[GKGameCenterViewController alloc] init];
if (gameCenterController != nil) {
gameCenterController.gameCenterDelegate = self;
gameCenterController.viewState = GKGameCenterViewControllerStateAchievements;
[viewController presentViewController:gameCenterController animated:YES completion:nil];
}
}
Note that the view controller trying to use these functions will need to pass itself (i.e. viewController param must be set to some active view controller).
Hope this helps.

Answer 4

Use GKGameCenterViewController and set the view state:
//Create a leaderboard view controller
GKGameCenterViewController *leaderboardViewController = [[GKLeaderboardViewController alloc] init];
leaderboardViewController.viewState = GKGameCenterViewControllerStateLeaderboards;
//Set the time scope (ex. All Time, This Week, Today) and the leaderboard ID
leaderboardViewController.timeScope = GKLeaderboardTimeScopeAllTime;
leaderboardViewController.leaderboardCategory = leaderboardID;
//Set the delegate so we can handle various actions including dismissal
leaderboardViewController.leaderboardDelegate = self;
//Present the view controller
[self presentViewController:leaderboardViewController animated:YES completion:nil];
This code will present a view controller that displays all of your games leaderboards (or the rankings if there is only one). You can also set properties such as which leaderboard to show, the time scope, delegate, etc. Also note that you can do a similar thing with achievements using the GKAchievementViewController.
The code that you provided in your question,
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:#"gamecenter:"]];
Launches the GameCenter app. This means that iOS will exit your app and switch to GameCenter. This could be confusing to the user. You should also avoid making the user leave your app. Instead, use the GKViewControllers which are presented modally inside of your app.