How to retrieve every possible contact?

Question

There is multiple examples of how we could retrieve contacts in android the most common type is using ContactsContract like this:

ContentResolver resolver = getContentResolver();
Cursor cursor = resolver.query(ContactsContract.contacts.CONTENT_URI,null,null,null,null);

while(cursor.moveToNext){
//get contact details
.........

}

My Question:

If users can save their contacts in three places phone, SIM, google_account. Then how I am able to use a method that retrieves all numbers that a user have on the phone?

Also as the contact list in the phone duplicates contacts how can we avoid getting a contact twice or 4 times or 5 times?

What would be the method that one must use to cover all possible contacts once?

Answer 1

Users can actually save contacts in many places, not just 3, e.g. if a user installs the Yahoo app, they can start storing contacts on Yahoo as well, same goes for Outlook, etc.

The ContactsContract covers all these options, and provides a single API to query for all contacts stored on the device. The different storage types are distinguished by ACCOUNT_NAME and ACCOUNT_TYPE at the RawContact level.

a Contact result you get from your query, is actually an aggregation of multiple RawContacts coming from one or more origins or ACCOUNT_TYPEs, so duplicate RawContacts on your SIM and Phone should aggregate into a single Contact

Here's some code to explore your own contacts on your device (this is very slow code, there are ways to improve performance significantly):

String[] projection = new String[] { Contacts._ID, Contacts.DISPLAY_NAME};
Cursor contacts = resolver.query(ContactsContract.Contacts.CONTENT_URI, projection, null, null, null);

while (contacts.moveToNext()) {

    long contactId = contacts.getLong(0);
    String name = contacts.getString(1);

    Log.i("Contacts", "Contact " + contactId + " " + name + " - has the following raw-contacts:");

    String[] projection2 = new String[] { RawContacts._ID, RawContacts.ACCOUNT_TYPE, RawContacts.ACCOUNT_NAME };
    Cursor raws = resolver.query(RawContacts.CONTENT_URI, null, RawContacts.CONTACT_ID, null, null);

    while (raws.moveToNext()) {

        long rawId = raws.getLong(0);
        String accountType = raws.getString(1);
        String accountName = raws.getString(2);

        Log.i("Contacts", "\t RawContact " + rawId + " from " + accountType + " / " + accountName);
    }
    raws.close();
}
contacts.close();