问题
If I register a content observer on say the calendar database is there a way to get exactly what changed in the database when an event gets edited?
回答1:
Can't be done...Diane Hackborn claims it's intentional. You'll have to requery or use a sync adapter.
回答2:
Make use of shared preferences and content providers along with content observer.
When I read the DB, I know that I have read all the entries until the time stored in shared preferences. So each time I read DB, I need to check for all the changes after the time that was stored in shared preferences and update the time in the shared preferences to current time(after doing whatever you wanted to do with these new entries).
来源：https://stackoverflow.com/questions/7285903/content-observer-changes