//POJO


public class Contact {
    public String name = "";
    public String number = "";
    public String id = "";


    public Contact(String name, String phoneNumber){
        this.name = name;
        this.number = phoneNumber;
    }


    public void setName(String name) {
        this.name = name;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public String getNumber() {
        return number;
    }

    public String getId() {
        return id;
    }


}


//method to retrieve all contacts and put into arraylist

public static ArrayList<Contact> getContactsList(Context context) {
        ArrayList<Contact> contacts=new ArrayList<>();
        Cursor phones = context.getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                null, null, null, null);
        while (phones.moveToNext())
        {
            String name=phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
            String phoneNumber = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
            contacts.add(new Contact(name,phoneNumber));
        }
        phones.close();
        Collections.sort(contacts, new Comparator<Contact>() {
            public int compare(Contact v1, Contact v2) {
                return v1.getName().compareTo(v2.getName());
            }
        });
        return contacts;
    }