.dart

class CustomerListScreen extends StatelessWidget {

  final customers = ["Alex", "John", "Bryan", "Jerry", "Mary"];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Customers")
      ), 
      body: CustomerList(customers: customers, onSelected: (customer) {
        Navigator.push(context, MaterialPageRoute(
          builder: (context) => CustomerDetailScreen(customer: customer)
        ));
      }) 
    );
  }
}