Using Grand Central Dispatch with GKLeaderboard - ios

Question

I've ran into a problem, I'm currently using GKLeaderboards and using it to fill a model. I'm having no problems fetching the data, my problem occurs when I go to fill the tableView with the data, and it's not done filling the array before its called to fill the TableView. From what i've read i need to use Grand Central Dispatch so that its not loading on the main thread.
Any help would be much appreciated.
+(EILeaderBoardModel *)scoresAndNameFromLeaderBoard
{
static EILeaderBoardModel *leaderBoard = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
leaderBoard = [[EILeaderBoardModel alloc] init];
leaderBoard.highScorePlayerArray = [[self class] GameCenterLeaderBoard];
});
return leaderBoard;
}
+ (NSMutableArray *)GameCenterLeaderBoard
{
NSMutableArray *_highScorePlayer = [NSMutableArray new];
GKLeaderboard *leaderboardRequest = [[GKLeaderboard alloc] init];
leaderboardRequest.playerScope = GKLeaderboardPlayerScopeGlobal;
leaderboardRequest.timeScope = GKLeaderboardTimeScopeAllTime;
leaderboardRequest.range = NSMakeRange(1, 20);
leaderboardRequest.identifier = GameHighscoreIdentifier;
[leaderboardRequest loadScoresWithCompletionHandler: ^(NSArray *scores, NSError *error) {
if (error != nil)
{
// Handle the error.
}
if (scores != nil)
{
for (NSUInteger i = 0; i < scores.count; i++) {
GKScore *score = (GKScore *)scores[i];
[GKPlayer loadPlayersForIdentifiers:#[score.playerID] withCompletionHandler:^(NSArray *players, NSError *error) {
GKPlayer *player = (GKPlayer *)players[0];
[player loadPhotoForSize:GKPhotoSizeSmall withCompletionHandler:^(UIImage *photo, NSError *error) {
if (error != nil) {
}
UIImage *_avatar;
if (photo != nil) {
_avatar = photo;
} else {
_avatar = [UIImage imageNamed:#"unknownPersonImage.png"];
}
EIPlayer *currentPlayer = [EIPlayer nameLabel:player.displayName
scoreLabel:[NSString stringWithFormat:#"%llD",score.value]
avatar:_avatar];
[_highScorePlayer addObject:currentPlayer];
}];
}];
}
}
}];
return _highScorePlayer;
}

Answer 1

dispatch_queue_t queue = dispatch_queue_create("com.yourQueue.company", 0);
dispatch_queue_t main = dispatch_get_main_queue();
dispatch_async(queue, ^{
// Do all your data fetching work here
// also like adding values to arrays.
dispatch_async(main, ^{
// Do all your UI update logic here like updating data into tables.
[self.tableView reloadData];
});
});
hope this helps.