xcode 如何从 iOS 中的 EKCalendar 获取所有事件
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How to get all events from an EKCalendar in iOS
提问by Lofens
I've created a calendar with some events, now I want to get all events from that calendar, without knowing what their start or end date is.
我已经创建了一个包含一些事件的日历，现在我想从该日历中获取所有事件，而不知道它们的开始或结束日期是什么。
Code I tried, getting all events from all calendars, so I could divide them by calendar ID later or so.. :
我试过的代码，从所有日历中获取所有事件，所以我可以稍后按日历 ID 划分它们..：
NSPredicate *fetchCalendarEvents = [eventStore predicateForEventsWithStartDate:[NSDate distantPast] endDate:[NSDate distantFuture] calendars:eventStore.calendars];
NSArray *allEvents = [eventStore eventsMatchingPredicate:fetchCalendarEvents];
This makes allEventsreturn nilwhile the database clearly shows events in the calendar.
这在数据库清楚地显示日历中的事件时allEvents返回nil。
Anyone could help me?
任何人都可以帮助我吗？
回答by Lofens
I have it working now.
我现在可以工作了。
This is the code I'm using:
这是我正在使用的代码：
NSDate* endDate = [NSDate dateWithTimeIntervalSinceNow:[[NSDate distantFuture] timeIntervalSinceReferenceDate]];
NSArray *calendarArray = [NSArray arrayWithObject:cal];
NSPredicate *fetchCalendarEvents = [eventStore predicateForEventsWithStartDate:[NSDate date] endDate:endDate calendars:calendarArray];
NSArray *eventList = [eventStore eventsMatchingPredicate:fetchCalendarEvents];
for(int i=0; i < eventList.count; i++){
NSLog(@"Event Title:%@", [[eventList objectAtIndex:i] title]);
}
Gives me all events from the calendar I'm using for my app from the date it is right when you call the method.
从您调用该方法的正确日期开始，我为我的应用程序提供日历中的所有事件。
I think giving [NSDate distantPast]won't work because it's in the past or something.. setting your startDate as [NSDate date]will work.
我认为给予是[NSDate distantPast]行不通的，因为它已经过去了，或者什么的……设置你的 startDate[NSDate date]会起作用。
Hope this helps people who have the same problem..
希望这可以帮助有同样问题的人..
回答by Momchil Marinov
If you would like to lookup a year span greater than 4 years, the returned events would be trimmed by the system to those from the first 4 years. (see Apple's documentation). What could be a possible solution is to run the predicate matching in batches.
如果您想查找超过 4 年的年份，系统会将返回的事件修剪为前 4 年的事件。（请参阅Apple 的文档）。可能的解决方案是批量运行谓词匹配。
Here's a C# extension for Xamarin.iOS
这是 Xamarin.iOS 的 C# 扩展
public static class EKEventStoreExtensions
{
private const int MaxPredicateYearSpan = 4;
public static EKEvent[] GetAllEvents(this EKEventStore eventStore, DateTimeOffset startAt, DateTimeOffset endAt, params EKCalendar[] calendars)
{
var isBatched = endAt.Year - startAt.Year >= MaxPredicateYearSpan;
var result = new List<EKEvent>();
var batchStartAt = startAt;
var batchEndAt = endAt;
while (batchStartAt < endAt)
{
if (isBatched)
{
batchEndAt = batchStartAt.AddYears(1);
if (batchEndAt > endAt)
{
batchEndAt = endAt;
}
}
var events = GetEventsMatching(eventStore, batchStartAt, batchEndAt, calendars);
result.AddRange(events);
batchStartAt = batchEndAt;
}
return result.ToArray();
}
private static EKEvent[] GetEventsMatching(EKEventStore eventStore, DateTimeOffset startAt, DateTimeOffset endAt, EKCalendar[] calendars)
{
var startDate = (NSDate)startAt.LocalDateTime;
var endDate = (NSDate)endAt.LocalDateTime;
var fetchCalendarEvents = eventStore.PredicateForEvents(startDate, endDate, calendars);
return eventStore.EventsMatching(fetchCalendarEvents);
}
}
