GraphQL In Flutter

GraphQL In Flutter :

This flutter tutorial post is GraphQL flutter.

• Query language.
• Send the query to the GraphQL Server. Server executes the query at runtime for fulfilling those queries with get the data.
• Structured Query Language.

• ValueNotifier notified to their listener whenever there is any value change.

Screenshot:

main.dart

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

void main() {
  runApp(MaterialApp(title: "GQL App", home: MyApp()));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final HttpLink httpLink =
        HttpLink(uri: "https://countries.trevorblades.com/");
    final ValueNotifier<GraphQLClient> client = ValueNotifier<GraphQLClient>(
      GraphQLClient(
        link: httpLink,
        cache: OptimisticCache(
          dataIdFromObject: typenameDataIdFromObject,
        ),
      ),
    );
    return GraphQLProvider(
      child: HomePage(),
      client: client,
    );
  }
}

class HomePage extends StatelessWidget {
  final String query = r"""
                    query GetContinent($code : String!){
                      continent(code:$code){
                        name
                        countries{
                          name
                        }
                      }
                    }
                  """;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("GraphlQL Client"),
        ),
        body: Query(
            options: QueryOptions(
                document: query, variables: <String, dynamic>{"code": "AS"}),
            builder: (QueryResult result,
                {VoidCallback refetch, FetchMore fetchMore}) {
              if (result.errors != null) {
                return Text(result.errors.toString());
              }

              if (result.loading) {
                return Center(child: CircularProgressIndicator());
              }

              return ListView.builder(
                itemBuilder: (BuildContext context, int index) {
                  return ListTile(
                    title: Text(
                        result.data['continent']['countries'][index]['name']),
                  );
                },
                itemCount: result.data['continent']['countries'].length,
              );
            }));
  }
}

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