How to check if a number in my contacts is registered to Whatsapp?

Question

But I need this with numbers with country codes (like starting with +123 456 78 90 -that's the way I add the number as a contact) I need a function/class to check if this number has Whatsapp. I need this for an .apk I made in Android Studio.

Answer 1

 private void getAllWhatsappNumbers()
{
    //This class provides applications access to the content model.
    ContentResolver cr = context.getContentResolver();

//RowContacts for filter Account Types
    Cursor contactCursor = cr.query(
            ContactsContract.RawContacts.CONTENT_URI,
            new String[]{ContactsContract.RawContacts._ID,
                    ContactsContract.RawContacts.CONTACT_ID},
            ContactsContract.RawContacts.ACCOUNT_TYPE + "= ?",
            new String[]{"com.whatsapp"},
            null);



    if (contactCursor != null) {
        if (contactCursor.getCount() > 0) {
            if (contactCursor.moveToFirst()) {
                do {
                    //whatsappContactId for get Number,Name,Id ect... from  ContactsContract.CommonDataKinds.Phone
                    String whatsappContactId = contactCursor.getString(contactCursor.getColumnIndex(ContactsContract.RawContacts.CONTACT_ID));

                    if (whatsappContactId != null) {
                        //Get Data from ContactsContract.CommonDataKinds.Phone of Specific CONTACT_ID
                        Cursor whatsAppContactCursor = cr.query(
                                ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                                new String[]{ContactsContract.CommonDataKinds.Phone.CONTACT_ID,
                                        ContactsContract.CommonDataKinds.Phone.NUMBER,
                                        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME},
                                ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = ?",
                                new String[]{whatsappContactId}, null);

                        if (whatsAppContactCursor != null) {
                            whatsAppContactCursor.moveToFirst();
                            String id = whatsAppContactCursor.getString(whatsAppContactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.CONTACT_ID));
                            String name = whatsAppContactCursor.getString(whatsAppContactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                            String number = whatsAppContactCursor.getString(whatsAppContactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                            Log.d("log1","no:"+number+"name:"+name);
                            whatsAppContactCursor.close();

                            //Add Number to ArrayList
                            myWhatsappContactsNumbers.add(number);
                        }
                    }
                } while (contactCursor.moveToNext());
                contactCursor.close();
            }
        }
    }
}

With this function provided, we can get contact list on "com.whatsapp" We put this contact list in to the array list so we need a function to show us we the number we sent is in the list (true) or not (false). How can we achieve that?