CONTACT_ID - Keeping it in sync

I am interested in your opinions on the best way to keep a robust reference to a contact starting android 2.0. I have read a lot regarding this issue but i don't know which technique is advisable and if there's any new ones. Below are the 3 options i found so far:

1- Don't use your own db. Extend the c开发者_开发知识库ontacts.contract to write your data

2 - Use ContentObserver to keep track of any changes made to the contacts. This technique would however require your application to be running

3- Store all RAW contact IDs related to a CONTACT_ID in your db and infer the content of the aggregate contact from all its constituent RAW contacts

In my case i need to keep a separate db and i was wondering if there's any other new technique of keeping the CONTACT_ID current after aggregations and dis-aggregations...

Please advise

I am playing with the new Contacts API at the moment, writing an app which is also a source of contact data. I can't recommend #3 at all. To get all of "my" contact data I simply store them with a magic value in the RawContacts.SYNC1 field and query the contacts content provider for that when my app starts up.

Re. your question, don't use CONTACT_IDs, as they are volatile. Use the lookup API, i.e. if you have a raw contact ID, use RawContacts.getContactLookupUri() to get to the Contact. Likewise if some API gives you a contact ID, use Contacts.getLookupUri() to get a persistent identifier you can use later on.