iOS Client to Endpoints Backend query to get Students for GradeRecorder

queryForStudents.m

+ (void) _queryForStudentsWithPageToken:(NSString*) pageToken withCallback:(void (^)()) callback {
    GTLServiceGraderecorder* service = [RHOAuthUtils getService];
    GTLQueryGraderecorder* query = [GTLQueryGraderecorder queryForStudentList];
    query.limit = 10;
    query.pageToken = pageToken;
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
    [service executeQuery:query completionHandler:^(GTLServiceTicket* ticket,
                                                    GTLGraderecorderStudentCollection* studentCollection,
                                                    NSError* error){
        [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
        if (error != nil) {
            NSLog(@"Unable to query for students %@", error);
            [RHDialogUtils showErrorDialog:error];
            __isQueryInProgress = NO;
            return;
        }

        // Add the new students to the array and the maps.
        [__students addObjectsFromArray:studentCollection.items];
        for (GTLGraderecorderStudent* student in studentCollection.items) {
            // Add this student to the array of students for the team.
            if (student.team) {
                NSMutableArray* teamMembers = [__teamMap objectForKey:student.team];
                if (teamMembers == nil) {
                    teamMembers = [[NSMutableArray alloc] init]; // First student on team.
                }
                [teamMembers addObject:student];
                [__teamMap setObject:teamMembers forKey:student.team];
            }
        }

        // See if there are more students on the server.
        if (studentCollection.nextPageToken != nil) {
            NSLog(@"Finished query but there are more students!  So far we have %d students.",
                  (int)__students.count);
            [self _queryForStudentsWithPageToken:studentCollection.nextPageToken withCallback:callback];
        } else {
            NSLog(@"Finished all student queries.  Ended up with %d students.", (int)__students.count);
            __isQueryInProgress = NO;
            if (callback != nil) {
                callback(); // Could also use a notification, but I prefer callback blocks.
            }
        }
    }];
}