iOS 日历提醒.md

EventKit:创建、查看、编辑日历和提醒事件.

苹果文档

• https://developer.apple.com/library/archive/documentation/DataManagement/Conceptual/EventKitProgGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40004759-SW1
• https://developer.apple.com/documentation/eventkit?language=objc

EKEventStore

• eventStoreIdentifier:如果store被损坏,会产生一个新的eventStoreIdentifier.

//EventStore类似数据库, 频繁访问, 使用一个单例
- (EKEventStore *)sharedEKEventStore
{
    static EKEventStore *eventStore = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        eventStore = [[EKEventStore alloc] init];
    });
    return eventStore;
}

Searching Calendars

主要两种方法:

方法一:根据日历的时间、标题等这些属性，根据EKEventStore中的日历事件，找到相同的事件。

- enumerateEventsMatchingPredicate:usingBlock:
- eventsMatchingPredicate:
- fetchRemindersMatchingPredicate:completion:

predicate必须使用下面的Predicate创造, 苹果文档明确给出了注释.

方法二:根据EKEvent的eventIdentifier EKEvent的唯一标识.

需要保存在服务器根据设备ID,不能放在本地.比如:用户卸载后又重新安装的情况.

建议:在查询的时候,最好两个方法结合,优先使用EKEvent的eventIdentifier, App本地保存一份eventIdentifier,如果本地没有的话再使用Predicate.

//查询事件
-(EKEvent *)queryEKEventForIdentifierKey:(NSString *)calendarIdentifierKey{

    
    EKAuthorizationStatus authorizationStatus = [EKEventStore authorizationStatusForEntityType:EKEntityTypeEvent];
    if (authorizationStatus != EKAuthorizationStatusAuthorized) {
        return nil;
    }
    //只有授权后才能访问
    //优先使用本地缓存的eventIdentifier做判断.
    NSString *identifier = [[NSUserDefaults standardUserDefaults] stringForKey:calendarIdentifierKey];
    if (identifier && identifier.length>0) {
        EKEvent *event = [[self sharedEKEventStore] eventWithIdentifier:identifier];
        return event;
    }
    
    ///使用predicent: 查询的是从现在到后面1年
    NSCalendar *calendar = [NSCalendar currentCalendar];
    // Create the start date components: 从今天0:0开始
    NSDateComponents *nowdateComponents = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay  fromDate:[NSDate date]];
    NSDateComponents *startDateComponents = [[NSDateComponents alloc] init];
    [startDateComponents setDay:nowdateComponents.day];
    [startDateComponents setMonth:nowdateComponents.month];
    [startDateComponents setYear:nowdateComponents.year];
    [startDateComponents setHour:0];
    [startDateComponents setMinute:0];
    NSDate *startDate = [calendar dateFromComponents:startDateComponents];
    
    // Create the end date components
    NSDateComponents *oneYearFromNowComponents = [[NSDateComponents alloc] init];
    oneYearFromNowComponents.year = 1;
    NSDate *oneYearFromNow = [calendar dateByAddingComponents:oneYearFromNowComponents
                                                       toDate:[NSDate date]
                                                      options:0];
    EKCalendar *tempCalendar = [[self sharedEKEventStore] defaultCalendarForNewEvents];
    NSMutableArray *calendars = [NSMutableArray array];
    if (!tempCalendar) {
        calendars = nil;
    }else{
        [calendars addObject:tempCalendar];
    }
    
    NSPredicate *predicate = [[self sharedEKEventStore] predicateForEventsWithStartDate:startDate endDate:oneYearFromNow calendars:calendars];
    NSArray *events = [[self sharedEKEventStore] eventsMatchingPredicate:predicate];
    EKEvent *resultEvent = nil;
    if (events && [events isKindOfClass:[NSArray class]] && events.count>0) {
        for (EKEvent *event in events) {
            if ([event.title rangeOfString:@"六六大顺"].location != NSNotFound &&
                [event.title rangeOfString:@"签到"].location != NSNotFound) {
                resultEvent = event;
                break;
            }
        }
    }
    return resultEvent;
    
}

Predicate

- predicateForEventsWithStartDate:endDate:calendars:
- predicateForRemindersInCalendars:
- predicateForCompletedRemindersWithCompletionDateStarting:ending:calendars:
- predicateForIncompleteRemindersWithDueDateStarting:ending:calendars:

EKEvent相关属性

URL

用来给日历事件添加URL, 一般用“unlink/schema/短链”来跳转到自己app的特定页面.
event.URL = [NSURL URLWithString:urlStr];
注意: 系统日历中, 呈现给用户的是其decode一次后的url. 你可以将自己的URL放在notes(不会被decode)中.

Error Domain=EKErrorDomain Code=1 "尚未设定日历。" UserInfo={NSLocalizedDescription=尚未设定日历。}

非代码问题, 打开日历, 可以看到右上角“+”是灰色的, 说明本身是不可添加日历事件的.
解决方法: 设置->账号—>iCloud->日历, 切换下开关, 并重启日历, 看右上角"+"是否可用.