FaceBook登录后获取 用户昵称

 [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me" parameters:nil] startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
                     OSLog(@"CHKELSE --------------- user : %@",result);
                     NSDictionary *resultDict = (NSDictionary *)result;
                     NSString *userName = resultDict[@"name"];
                     
                     // 悬浮窗支付按钮使用
                     DataSupplier *dataSupplier = [DataSupplier sharedDataSupplier];
                     dataSupplier.payUserName = userName;
                     
                 }];