iOS calendar program tutorial

iOS에서 캘린더에 접근하는 방법.

1. header

  - @import EventKit;

2. Getting Permission.

- (void)requestAccessToEvents:(void (^)(BOOL bGranted))complete {
    BOOL needsToRequestAccessToEventStore = NO;
    EKAuthorizationStatus authorizationStatus = EKAuthorizationStatusAuthorized;
    if ([[EKEventStore class] respondsToSelector:@selector(authorizationStatusForEntityType:)]) {
        authorizationStatus = [EKEventStore authorizationStatusForEntityType:EKEntityTypeEvent];
        needsToRequestAccessToEventStore = (authorizationStatus == EKAuthorizationStatusNotDetermined);
    }
 
    if (needsToRequestAccessToEventStore) {
        [self.eventManager.eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
            if (granted) {
                NSLog(@"event just granted");
                complete(YES);
            }
        }];
    } else if (authorizationStatus == EKAuthorizationStatusAuthorized) {
        NSLog(@"event granted");
        complete(YES);
    } else {
        // TODO : Access denied popup
        NSLog(@"event access denied");
        complete(NO);
    }
}

3. Getting Calendars

- (NSArray *)getSuitableEventCalendars{
    // get all calendars
    // 모든 캘린더를 가져온다.
    NSArray *allCalendars = [self.eventStore calendarsForEntityType:EKEntityTypeEvent];
    
    // extract local calendars and GMail calendars only.
    // 그중에서 로컬캘린더와 구글 캘린더만 추출.
    NSMutableArray *suitableCalendars = [NSMutableArray array];
    for (int i=0; i<allCalendars.count; i++) {
        EKCalendar *currentCalendar = [allCalendars objectAtIndex:i];
        if ((currentCalendar.type == EKCalendarTypeLocal)
            || ([currentCalendar.source.title isEqualToString:@"GMail"])){
            [suitableCalendars addObject:currentCalendar];
        }
    }
    
    return (NSArray *)suitableCalendars;
}

3. Getting Events (Todo)

-(NSArray *)getEventsOfCalendar:(NSString *)calendarIdentifier {
 
    EKCalendar *selectedCalendar = nil;
    // There is function "calendarWithIdentifier" but the "Error getting shared calendar invitations for entity types 3" occured when you use. (nobody know the reason why)
    // calendarWithIdentifier 함수가 있으나, "Error getting shared calendar invitations for entity types 3" 에러남. (왜 나는지 아무도 모름)
    // so... we use if-clauses.
    // 따라서.. 다 가져와서 비교한다.
    NSArray *allCalendars = [self getSuitableEventCalendars];
    for (EKCalendar *calendar in allCalendars) {
        if ([calendar.calendarIdentifier isEqualToString:calendarIdentifier]) {
            selectedCalendar = calendar;
            break;
        }
    }
    
    if (selectedCalendar == nil) {
        return nil;
    }
    
    NSArray *calendarsArray = @[selectedCalendar];
    
    // whenever you setted endDate, iOS will return 4years of events after startDate (nobody know the reason why)
    // 캘린더 이벤트는 endDate가 언제든지 startDate로부터 4년 단위로밖에 나오지 않음. 모든 캘린더 이벤트를 가져오려면 loop를 돌아야 한다. (왜 그러는지 아무도 모름)
    NSMutableSet *eventsSet = [NSMutableSet set];
    NSDate *endDate =  [NSDate dateWithTimeIntervalSinceNow:[[NSDate distantFuture] timeIntervalSinceReferenceDate]]; // no end
    for (NSTimeInterval startTime=0; startTime < endDate.timeIntervalSince1970; startTime += (60 * 60 * 24 * 365 * 4)) {
        NSDate *startDate = [NSDate dateWithTimeIntervalSince1970:startTime];
        NSPredicate *predicate = [self.eventStore predicateForEventsWithStartDate:startDate endDate:endDate calendars:calendarsArray];
        NSArray *events = [self.eventStore eventsMatchingPredicate:predicate];
        if (0 < events.count) {
            [eventsSet addObjectsFromArray:events];
        }
    }
    
    // 정렬해서 리턴
    // return with sort.
    return [[eventsSet allObjects] sortedArrayUsingSelector:@selector(compareStartDateWithEvent:)];
}
 

4. you can access iOS events finally !!