Get a contact's groups?

Question

I\'m trying to make a many-to-many mapping of contacts to groups.

For example, if I have:

• User 1, belongs to group 701, 702, 704
• User 2, belon

Answer 1

 public static HashMap getContactsForGroup(String groupID, Activity activity){
    Cursor dataCursor = activity.getContentResolver().query(
            ContactsContract.Data.CONTENT_URI,
            new String[]{                                                       // PROJECTION
                    ContactsContract.Data.CONTACT_ID,
                    ContactsContract.Data.DISPLAY_NAME,         // contact name
                    ContactsContract.Data.DATA1                 // group
            },
            ContactsContract.Data.MIMETYPE + " = ? " + "AND " +                 // SELECTION
            ContactsContract.Data.DATA1 +    " = ? ",           // set groupID
            new String[]{                                                       // SELECTION_ARGS
                    ContactsContract.CommonDataKinds.GroupMembership.CONTENT_ITEM_TYPE,
                    groupID
            },
            null
    );

    dataCursor.moveToFirst();
    HashMap map = new HashMap<>();
    while (dataCursor.moveToNext()) //
    {
        String s0 = dataCursor.getString(0);                //contact_id
        String s1 = dataCursor.getString(1);                //contact_name
        String s2 = dataCursor.getString(2);                //group_id
        Log.d("tag", "contact_id: " + s0 + "  contact: " + s1 + "   groupID: "+ s2);
        map.put(s0, s1);
    }
    return map;
}