Navigator push

contact_list_view.dart

class _ContactListState extends State<ContactList> implements ContactListViewContract {

  // ...

  List<_ContactListItem> _buildContactList() {
    return _contacts.map((contact) =>
                          _ContactListItem (
                            contact: contact,
                            onTap: () { _showContactPage(context, contact); }
                          ))
                    .toList();
  }

  void _showContactPage(BuildContext context, Contact contact) {
    Navigator.push(context, MaterialPageRoute<Null>(
      settings: const RouteSettings(name: ContactPage.routeName),
      builder: (BuildContext context) => ContactPage(contact)
    ));
  }
  
}