No one here seems to answer your question.
The reason you're seeing duplicate contacts is that you're querying for phones not contacts.
In Android there are 3 main tables:
Contacts table - has one item per contactRawContacts table - has one item per-contact per-account (such as Google, Outlook, Whatsapp, etc.) - multiple RawContacts are linked to a single ContactData table - has one item per detail (name, email, phone, address, etc.) - each data item is linked to a single RawContact, and multiple Data rows are linked to each RawContact.
You're querying on CommonDataKinds.Phone.CONTENT_URI which is a part of the Data table, so if a contact has more then one phone, and/or it has the same phone from multiple sources (e.g. Google and Whatsapp) you'll get the same phone with the same CONTACT_ID more then once.
The solution would be, to use a HashMap (rather then a HashSet), where the key is CONTACT_ID, so you can display multiple phones per contact:
String[] projection = new String[] { CommonDataKinds.Phone.CONTACT_ID, CommonDataKinds.Phone.DISPLAY_NAME, CommonDataKinds.Phone.NUMBER };
Cursor cursor = getContentResolver().query(CommonDataKinds.Phone.CONTENT_URI, projection, null, null, null);
HashMap<Long, Contact> contacts = new HashMap<>();
while (cursor.moveToNext()) {
long id = cursor.getLong(0);
String name = cursor.getString(1);
String phone = cursor.getString(2);
Contact c = contacts.get(id);
if (c == null) {
// newly found contact, add to Map
c = new Contact();
c.name = name;
contacts.put(id, c);
}
// add phone to contact class
c.phones.add(phone);
}
cursor.close();
// simple class to store multiple phones per contact
private class Contact {
public String name;
// use can use a HashSet here to avoid duplicate phones per contact
public List<String> phones = new ArrayList<>();
}
If you want to sort your HashMap by name:
List<Contact> values = new ArrayList<>(contacts.values());
Collections.sort(values, new Comparator<Contact> {
public int compare(Contact a, Contact b) {
return a.name.compareTo(b.name);
}
});
// iterate the sorted list, per contact:
for (Contact contact : values) {
Log.i(TAG, "contact " + contact.name + ": ");
// iterate the list of phones within each contact:
for (String phone : contact.phones) {
Log.i(TAG, "\t phone: " + phone);
}
}
HASHSET– Lightface