我有两个无符号整数，a 和 b。现在我的目标是获得两者之间差异的绝对值。
目前我正在做的是：
uint64_t a, b;
llabs((int64_t)(a - b))
这似乎有效，但我不确定是否有效。有人能证实吗？
所以我在阅读苹果文档后感到疑惑(https://developer.apple.com/library/ios/documentation/GameKit/Reference/GKLeaderboard_Ref/Reference/Reference.html#//apple_ref/occ/instp/GKLeaderboard/category)如何创建一个UITableView并用localPlayers Game Center朋友填充它,并在特定的排行榜中得分.我知道如何使用loadScoresWithCompletionHandler:方法单独获取好友列表和好友分数.
编辑:到目前为止,我得到了这个以获得个人朋友的照片,得分和显示名称保存到一个NSArray.但我无法弄清楚如何在UITableView中显示它们.
- (void) loadPlayerData: (NSArray *) identifiers
{
GKLeaderboard *leaderboardRequest = [[GKLeaderboard alloc] init];
if (leaderboardRequest != nil) {
leaderboardRequest.playerScope = GKLeaderboardPlayerScopeFriendsOnly;
leaderboardRequest.timeScope = GKLeaderboardTimeScopeAllTime;
leaderboardRequest.category = @"MJ_IL";
[leaderboardRequest loadScoresWithCompletionHandler: ^(NSArray *scores, NSError *error) {
if (error != nil) {
// handle the error. if (scores != nil)
}
if (scores != nil){
for (GKScore* score in scores) {
NSArray *playerIdArray = [NSArray arrayWithObject:score.playerID];
[GKPlayer loadPlayersForIdentifiers:playerIdArray withCompletionHandler:^(NSArray *players, NSError *error) {
GKPlayer *player = [players …我有一系列if语句来检查我是否登录.
- (void)webViewDidFinishLoad:(UIWebView *)webView {
if ([webView.request.URL isEqual:@"http://www.tapgram.com/login"]) {
NSLog(@"on log in page: %@", webView.request.URL);
} else if ([webView.request.URL isEqual:@"http://www.tapgram.com/loginfailed?alert_message=Failed+login&came_from=%2F"]){
NSLog(@"failed log in: %@", webView.request.URL);
[keychainItem resetKeychainItem];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Incorrect Credentials" message:@"It seems that either your username or password is incorrect. Please try agian." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[alert show];
} else if (![webView.request.URL isEqual:@"http://www.tapgram.com/login"]) {
NSLog(@"logged in: %@", webView.request.URL);
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
ViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"];
[vc setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self presentViewController:vc animated:YES completion:nil]; …