选择其他日历时，EKEvent标识符会更改

Question

I have a meeting planner app that has its own sqlite database and attaches it self to an EKEvent from the calendar framework. I'm using the event identifier as a foreign key for my meeting data. The problem resides when a user changes the event's calendar in the calendar application. The identifier changes and I got no way of knowing that it changed since it was made outside my app. Please let me know if anyone has any ideas

Answer 1

从iOS 5.0开始，无法确定地唯一标识事件

Answer 2

The documentation warns that "If the calendar of an event changes, its identifier most likely changes as well."

Another gotcha is that all instances of a repeating event have the same identifier; -[EKEventStore eventWithIdentifier:] seems to return the first instance. (I've even seen events with a nil identifier; I can't remember what the exact cause is.)

If -eventWithIdentifier: returns a non-repeating event, then you're probably good to go. Otherwise, the easiest way around both of these is probably to search all calendars for events at around the same time and use a heuristic to determine the best match, or ask the user to pick the corresponding event if none of the matches are good enough.

You might also want to check what Google Calendar does when you edit a single instance of a repeating event (it might create an event with a new identifier and add a "hole" in the original event's repeat information, which may break your heuristic).

Answer 3

我现在正面临这个问题，试图在我的应用程序中保持同步的EventStore与内部数据库，我的解决方案是在应用程序内的EKEvents和事件之间进行映射，如果我发现匹配它没关系但是所有事件都没有将删除与EKEvents匹配的，并且将添加所有不匹配的EKEvents，这样做也会在同步期间添加刚刚被修改的EKEvents。