Calendars and Reminders

Event Kit architecture

SimpleEKDemo is an example sample code project that utilizes events in Event Kit.

不论是 Events 还是remainder 都是存储在 calendar database中，统一用类EKEventStore检索，

EKEventStore *store = [[EKEventStore alloc] init];

ios6中，加入权限：因此要用来判断是否有权限访问EKEntityTypeEvent ，EKEntityTypeReminder，

[store requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {

// handle access here

}];

Fetching events with a predicate

// Get the appropriate calendar

NSCalendar *calendar = [NSCalendar currentCalendar];

// Create the start date components

NSDateComponents *oneDayAgoComponents = [[NSDateComponents alloc] init];

oneDayAgoComponents.day = -1;

NSDate *oneDayAgo = [calendar dateByAddingComponents:oneDayAgoComponents

toDate:[NSDate date]

options:0];

// Create the end date components

NSDateComponents *oneYearFromNowComponents = [[NSDateComponents alloc] init];

oneYearFromNowComponents.year = 1;

NSDate *oneYearFromNow = [calendar dateByAddingComponents:oneYearFromNowComponents

toDate:[NSDate date]

options:0];

// Create the predicate from the event store's instance method

NSPredicate *predicate = [store predicateForEventsWithStartDate:oneDayAgo

endDate:oneYearFromNow

calendars:nil];

// Fetch all events that match the predicate

NSArray *events = [store eventsMatchingPredicate:predicate];

Retrieving Reminders

You can call fetchRemindersMatchingPredicate:completion: to access multiple reminders that match a predicate. Pass a predicate returned by one of the following methods:

• predicateForIncompleteRemindersWithDueDateStarting:ending:calendars: finds incomplete reminders within an optional time period

• predicateForCompletedRemindersWithCompletionDateStarting:ending:calendars: finds completed reminders within an optional time period

• predicateForRemindersInCalendars: finds all reminders

NSPredicate *predicate = [store predicateForRemindersInCalendars:nil];

[store fetchRemindersMatchingPredicate:predicate completion:^(NSArray *reminders) {

for (EKReminder *reminder in reminders) {

// do something for each reminder

}

}];

 calendarItemWithIdentifier: can fetch any calendar item (reminders and events), whereas eventWithIdentifier: fetches only events.

Observing External Changes to the Calendar Database

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(storeChanged:)

name:EKEventStoreChangedNotification

object:eventStore];

The Event Kit UI framework provides two types of view controllers for manipulating events:

• EKEventViewController: use this class if you have an existing event you want to display.

• EKEventEditViewController: use this class to allow the user to create, edit, or delete events.

EKEventViewController *eventViewController = [[EKEventViewController alloc] init];

eventViewController.event = myEvent;

eventViewController.allowsEditing = YES;

navigationController = [[UINavigationController alloc] initWithRootViewController:eventViewController];

EKEventEditViewController* controller = [[EKEventEditViewController alloc] init];

controller.eventStore = myEventStore;

controller.editViewDelegate = self;

[self presentModalViewController:controller animated:YES];

- (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.

if (self.defaultCalendar ==  thisEvent.calendar) {

[self.eventsList addObject:thisEvent];

}

[controller.eventStore saveEvent:controller.event span:EKSpanThisEvent error:&error];

[self.tableView reloadData];

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.

if (self.defaultCalendar ==  thisEvent.calendar) {

[self.eventsList removeObject:thisEvent];

}

[controller.eventStore removeEvent:thisEvent span:EKSpanThisEvent error:&error];

[self.tableView reloadData];

break;

default:

break;

}

// Dismiss the modal view controller

[controller dismissModalViewControllerAnimated:YES];

}