How to JOIN (literaly) two/more ContentProviders in Android?

Question

I have a ContentProvider with a DataBase having two columns named "_id" and "_name". First, i am copying the id and name from ContactsContract.CommonDataKinds.Phone. Then i need to change the data in my ContentProvider. Then i need to access id and name again from ContactsContract.CommonDataKinds.Phone but on the basis of those id (s) which are now in my **ContentProvider**.

I know how to use Join in two tables. But don't know how can i do this using ContentProviders.

Answer 1

Here is how I would do that:

Cursor locals = // Get from my local ContentProvider
Cursor distant = // Get from distant phone ContentProvider
List<String> names = new ArrayList<>();
CursorJoiner joiner = new CursorJoiner(locals, new String[] {"_id"}, distant, new String[] {"_id"});
for (CursorJointer.Result joinerResult : joiner) {
    switch (joinerResult) {
    case BOTH:
        String name = distant.getString(distant.getColumnIndex("name"));
        names.add(name);
        break;
    }
}

names contain your list of names.