main.dart

import 'package:flutter/material.dart';
import 'package:graphql_flutter/graphql_flutter.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final HttpLink httpLink = HttpLink(
//      uri: 'http://localhost:7474/graphql/',
        uri: 'https://countries.trevorblades.com/');

    final ValueNotifier<GraphQLClient> client = ValueNotifier<GraphQLClient>(
      GraphQLClient(
        link: httpLink,
        cache: InMemoryCache(),
      ),
    );

    return GraphQLProvider(
      client: client,
      child: CacheProvider(
        child: MaterialApp(
          title: 'GraphQLTest',
          home: HomePage(),
        ),
      ),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  String readExercise = """
  query{
      countries{
        name
      }
  }
  """;

//  query{
//  Movie{
//  title
//}
//}

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GraphQL client'),
      ),
      body: Query(
        options: QueryOptions(
          documentNode: gql(readExercise),
        ),
        builder: (QueryResult result,
            {VoidCallback refetch, FetchMore fetchMore}) {
          if (result.hasException) {
            return Text(result.exception.toString());
          }

          if (result.loading) {
            return Text('Loading');
          }

          // it can be either Map or List
          List repositories = result.data['countries'];

          return ListView.builder(
              itemCount: repositories.length,
              itemBuilder: (context, index) {
                final repository = repositories[index];

                return Text(repository['name']);
              });
        },
      ),
    );
  }
}