iOS calendar manager

HVPBaseCalendarViewController.h

//
//  HVPBaseCalendarViewController.h
//
//  Created by wwwins on 2014/8/5.
//  Copyright (c) 2014年 isobar. All rights reserved.
//
/*
 Usage:

 __weak HVPBaseCalendarViewController *weakSelf = self;
 [self checkEventStoreAccessForCalendar:^(){
  // 取得行事曆權限後執行 addEventAt
  [weakSelf addEventAt:[NSDate date]] withTitle:@"Title" withNotes:@"Description" inLocation:@"Place"];
 }];
*/

#import <EventKit/EventKit.h>
#import <EventKitUI/EventKitUI.h>

#import "HVPBaseViewController.h"

@interface HVPBaseCalendarViewController : HVPBaseViewController <EKEventEditViewDelegate>

// EKEventStore instance associated with the current Calendar application
@property (nonatomic, strong) EKEventStore *eventStore;

// Default calendar associated with the above event store
@property (nonatomic, strong) EKCalendar *defaultCalendar;

@property (nonatomic, copy) void(^completion)();

- (void)checkEventStoreAccessForCalendar:(void(^)())completion;
- (void)addEventAt:(NSDate *)startDate withTitle:(NSString *)title withNotes:(NSString *)notes inLocation:(NSString *)location;

@end

HVPBaseCalendarViewController.m

//
//  HVPBaseCalendarViewController.m
//
//  Created by wwwins on 2014/8/5.
//  Copyright (c) 2014年 isobar. All rights reserved.
//

#import "HVPBaseCalendarViewController.h"

@interface HVPBaseCalendarViewController ()

@end

@implementation HVPBaseCalendarViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
  [super viewDidLoad];
  // Do any additional setup after loading the view.

  // Initialize the event store
  if (!_eventStore) {
    _eventStore = [[EKEventStore alloc] init];
  }
  _completion = nil;

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark -
#pragma mark Access Calendar

// Check the authorization status of our application for Calendar
- (void)checkEventStoreAccessForCalendar
{
  EKAuthorizationStatus status = [EKEventStore authorizationStatusForEntityType:EKEntityTypeEvent];
  
  switch (status)
  {
      // Update our UI if the user has granted access to their Calendar
    case EKAuthorizationStatusAuthorized: [self accessGrantedForCalendar];
      break;
      // Prompt the user for access to Calendar if there is no definitive answer
    case EKAuthorizationStatusNotDetermined: [self requestCalendarAccess];
      break;
      // Display a message if the user has denied or restricted access to Calendar
    case EKAuthorizationStatusDenied:
    case EKAuthorizationStatusRestricted:
    {
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Privacy Warning" message:@"Permission was not granted for Calendar"
                                                     delegate:nil
                                            cancelButtonTitle:@"OK"
                                            otherButtonTitles:nil];
      [alert show];
    }
      break;
    default:
      break;
  }
}

- (void)checkEventStoreAccessForCalendar:(void(^)())completion
{
  _completion = completion;
  [self checkEventStoreAccessForCalendar];
}

// Prompt the user for access to their Calendar
-(void)requestCalendarAccess
{
  [_eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error)
   {
     if (granted)
     {
       __weak HVPBaseCalendarViewController *weakSelf = self;
       // Let's ensure that our code will be executed from the main queue
       dispatch_async(dispatch_get_main_queue(), ^{
         // The user has granted access to their Calendar; let's populate our UI with all events occuring in the next 24 hours.
         [weakSelf accessGrantedForCalendar];
       });
     }
   }];
}


// This method is called when the user has granted permission to Calendar
-(void)accessGrantedForCalendar
{
  // Let's get the default calendar associated with our event store
  _defaultCalendar = _eventStore.defaultCalendarForNewEvents;
  
  _completion();
}


#pragma mark -
#pragma mark Add a new event

// Display an event edit view controller when the user taps the "+" button.
// A new event is added to Calendar when the user taps the "Done" button in the above view controller.
- (void)addEventAt:(NSDate *)startDate withTitle:(NSString *)title withNotes:(NSString *)notes inLocation:(NSString *)location
{
  // Create an instance of EKEventEditViewController
  EKEventEditViewController *addController = [[EKEventEditViewController alloc] init];
  
  // create a event
  EKEvent *event = [EKEvent eventWithEventStore:_eventStore];
  event.title = title;
  event.notes = notes;
  event.location = location;
  
  event.startDate = startDate;
  event.endDate = [startDate dateByAddingTimeInterval:3600*24];
  
  // Set addController's event store to the current event store
  addController.event = event;
  addController.eventStore = _eventStore;
  addController.editViewDelegate = self;
  
  [self presentViewController:addController animated:YES completion:nil];
}

#pragma mark -
#pragma mark EKEventEditViewDelegate

// Overriding EKEventEditViewDelegate method to update event store according to user actions.
- (void)eventEditViewController:(EKEventEditViewController *)controller
          didCompleteWithAction:(EKEventEditViewAction)action
{
  NSError *error = nil;
  EKEvent *thisEvent = controller.event;
  switch (action) {
    case EKEventEditViewActionCanceled:
      // Edit action canceled, do nothing.
      break;
    case EKEventEditViewActionSaved:
      // When user hit "Done" button, save the newly created event to the event store,
      // and reload table view.
      // If the new event is being added to the default calendar, then update its
      // eventsList.
      [controller.eventStore saveEvent:controller.event span:EKSpanThisEvent error:&error];
      break;
    case EKEventEditViewActionDeleted:
      // When deleting an event, remove the event from the event store,
      // and reload table view.
      // If deleting an event from the currenly default calendar, then update its
      // eventsList.
      [controller.eventStore removeEvent:thisEvent span:EKSpanThisEvent error:&error];
      break;
    default:
      break;
  }
  
  // Dismiss the modal view controller
  [controller dismissViewControllerAnimated:YES completion:nil];
}


// Set the calendar edited by EKEventEditViewController to our chosen calendar - the default calendar.
- (EKCalendar *)eventEditViewControllerDefaultCalendarForNewEvents:(EKEventEditViewController *)controller
{
  return _defaultCalendar;
}


@end