Merge pull request zino-hofmann#691 from artflutter/flutter-bloc5-exm…

…aple-update

Updated `flutter_bloc` example to work with `flutter_bloc` lib v5

examples/flutter_bloc/lib/blocs/repos/my_repos_bloc.dart

@@ -14,9 +14,7 @@ class MyGithubReposBloc extends Bloc<MyGithubReposEvent, MyGithubReposState> {
   // this a bit of a hack
   List<Repo> githubRepositories;
 
-  MyGithubReposBloc({@required this.githubRepository});
-
-  MyGithubReposState get initialState => new ReposLoading();
+  MyGithubReposBloc({@required this.githubRepository}) : super(ReposLoading());
 
   @override
   Stream<MyGithubReposState> mapEventToState(

examples/flutter_bloc/lib/extended_bloc.dart

@@ -21,7 +21,7 @@ class _ExtendedBlocState extends State<ExtendedBloc> {
   void initState() {
     super.initState();
     _refreshCompleter = Completer<void>();
-    bloc = BlocProvider.of<RepositoriesBloc>(context);
+    bloc = BlocProvider.of<RepositoriesBloc>(context)..run();
   }
 
   Future _handleRefreshStart(Bloc bloc) {
@@ -54,22 +54,21 @@ class _ExtendedBlocState extends State<ExtendedBloc> {
                 builder: (_, state) {
                   Widget child = Container();
 
-                  if (state is GraphqlLoadingState) {
+                  if (bloc.isLoading) {
                     child = Center(child: CircularProgressIndicator());
                   }
 
-                  if (state is GraphqlErrorState<Map<String, dynamic>>) {
+                  if (bloc.hasError) {
                     _handleRefreshEnd();
                     child = ListView(children: [
                       Text(
-                        parseOperationException(state.error),
+                        bloc.getError,
                         style: TextStyle(color: Theme.of(context).errorColor),
                       )
                     ]);
                   }
 
-                  if (state is GraphqlLoaded ||
-                      state is GraphqlFetchMoreState) {
+                  if (bloc.hasData) {
                     _handleRefreshEnd();
                     final itemCount =
                         state.data['viewer']['repositories']['nodes'].length;
@@ -96,9 +95,7 @@ class _ExtendedBlocState extends State<ExtendedBloc> {
                           final pageInfo =
                               state.data['viewer']['repositories']['pageInfo'];
 
-                          if (index == itemCount - 1 &&
-                              state is GraphqlLoaded &&
-                              pageInfo['hasNextPage']) {
+                          if (bloc.shouldFetchMore(index, 1)) {
                             bloc.fetchMore(after: pageInfo['endCursor']);
                           }
 
@@ -109,8 +106,7 @@ class _ExtendedBlocState extends State<ExtendedBloc> {
                             title: Text(node['name']),
                           );
 
-                          if (state is GraphqlFetchMoreState &&
-                              index == itemCount - 1) {
+                          if (bloc.isFetchingMore && index == itemCount - 1) {
                             tile = Column(
                               children: [
                                 tile,
@@ -137,23 +133,3 @@ class _ExtendedBlocState extends State<ExtendedBloc> {
     );
   }
 }
-
-String parseOperationException(OperationException error) {
-  if (error.clientException != null) {
-    final exception = error.clientException;
-
-    if (exception is NetworkException) {
-      return 'Failed to connect to ${exception.uri}';
-    } else {
-      return exception.toString();
-    }
-  }
-
-  if (error.graphqlErrors != null && error.graphqlErrors.isNotEmpty) {
-    final errors = error.graphqlErrors;
-
-    return errors.first.message;
-  }
-
-  return 'Unknown error';
-}

examples/flutter_bloc/lib/extended_bloc/graphql/bloc.dart

@@ -1,22 +1,27 @@
 import 'dart:async';
-
 import 'package:bloc/bloc.dart';
 import 'package:graphql/client.dart';
 import 'package:meta/meta.dart';
 import 'package:graphql/internal.dart';
 
-import 'package:graphql_flutter_bloc_example/extended_bloc/graphql/event.dart';
-import 'package:graphql_flutter_bloc_example/extended_bloc/graphql/state.dart';
+import 'event.dart';
+import 'state.dart';
 
 abstract class GraphqlBloc<T> extends Bloc<GraphqlEvent<T>, GraphqlState<T>> {
   GraphQLClient client;
   ObservableQuery result;
   WatchQueryOptions options;
 
-  GraphqlBloc({@required this.client, @required this.options}) {
+  GraphqlBloc({@required this.client, @required this.options})
+      : super(GraphqlInitialState<T>()) {
     result = client.watchQuery(options);
 
     result.stream.listen((QueryResult result) {
+      if (state is GraphqlRefetchState &&
+          result.source == QueryResultSource.Cache) {
+        return;
+      }
+
       if (result.loading && result.data == null) {
         add(GraphqlLoadingEvent<T>(result: result));
       }
@@ -31,19 +36,43 @@ abstract class GraphqlBloc<T> extends Bloc<GraphqlEvent<T>, GraphqlState<T>> {
       }
 
       if (result.hasException) {
-        add(GraphqlErrorEvent(error: result.exception, result: result));
+        add(GraphqlErrorEvent<T>(error: result.exception, result: result));
       }
     });
-
-    _runQuery();
   }
 
   void dispose() {
     result.close();
   }
 
+  void run() {
+    add(GraphqlRunQueryEvent<T>());
+  }
+
+  void refetch() {
+    add(GraphqlRefetchEvent<T>());
+  }
+
+  bool shouldFetchMore(int i, int threshold) => false;
+
+  bool get isFetchingMore => state is GraphqlFetchMoreState;
+
+  bool get isLoading => state is GraphqlLoadingState;
+
+  bool get isRefetching => state is GraphqlRefetchState;
+
   T parseData(Map<String, dynamic> data);
 
+  bool get hasData => (state is GraphqlLoadedState<T> ||
+      state is GraphqlFetchMoreState<T> ||
+      state is GraphqlRefetchState<T>);
+
+  bool get hasError => state is GraphqlErrorState<T>;
+
+  String get getError => hasError
+      ? parseOperationException((state as GraphqlErrorState<T>).error)
+      : null;
+
   Future<void> _runQuery() async {
     result.fetchResults();
   }
@@ -54,17 +83,18 @@ abstract class GraphqlBloc<T> extends Bloc<GraphqlEvent<T>, GraphqlState<T>> {
 
   void _refetch() => result.refetch();
 
-  @override
-  GraphqlState<T> get initialState => GraphqlInitialState<T>();
-
   @override
   Stream<GraphqlState<T>> mapEventToState(GraphqlEvent<T> event) async* {
+    if (event is GraphqlRunQueryEvent<T>) {
+      _runQuery();
+    }
+
     if (event is GraphqlLoadingEvent<T>) {
       yield GraphqlLoadingState<T>(result: event.result);
     }
 
     if (event is GraphqlLoadedEvent<T>) {
-      yield GraphqlLoaded<T>(data: event.data, result: event.result);
+      yield GraphqlLoadedState<T>(data: event.data, result: event.result);
     }
 
     if (event is GraphqlErrorEvent<T>) {
@@ -76,9 +106,29 @@ abstract class GraphqlBloc<T> extends Bloc<GraphqlEvent<T>, GraphqlState<T>> {
       _refetch();
     }
 
-    if (state is GraphqlLoaded && event is GraphqlFetchMoreEvent<T>) {
+    if (state is GraphqlLoadedState && event is GraphqlFetchMoreEvent<T>) {
       yield GraphqlFetchMoreState<T>(data: state.data, result: null);
       _fetchMore(event.options);
     }
   }
 }
+
+String parseOperationException(OperationException error) {
+  if (error.clientException != null) {
+    final exception = error.clientException;
+
+    if (exception is NetworkException) {
+      return 'Failed to connect to ${exception.uri}';
+    } else {
+      return exception.toString();
+    }
+  }
+
+  if (error.graphqlErrors != null && error.graphqlErrors.isNotEmpty) {
+    final errors = error.graphqlErrors;
+
+    return errors.first.message;
+  }
+
+  return 'Unknown error';
+}

examples/flutter_bloc/lib/extended_bloc/graphql/event.dart

@@ -1,32 +1,63 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
 import 'package:graphql/client.dart';
 import 'package:meta/meta.dart';
 
+part 'event.freezed.dart';
+
 abstract class GraphqlEvent<T> {}
 
-class GraphqlErrorEvent<T> extends GraphqlEvent<T> {
-  final OperationException error;
-  final QueryResult result;
+@freezed
+abstract class GraphqlErrorEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlErrorEvent<T> {
+  GraphqlErrorEvent._();
+
+  factory GraphqlErrorEvent({
+    @required OperationException error,
+    @required QueryResult result,
+  }) = _GraphqlErrorEvent<T>;
+}
+
+@freezed
+abstract class GraphqlRunQueryEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlRunQueryEvent<T> {
+  GraphqlRunQueryEvent._();
 
-  GraphqlErrorEvent({@required this.error, @required this.result});
+  factory GraphqlRunQueryEvent() = _GraphqlRunQueryEvent<T>;
 }
 
-class GraphqlLoadingEvent<T> extends GraphqlEvent<T> {
-  final QueryResult result;
+@freezed
+abstract class GraphqlLoadingEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlLoadingEvent<T> {
+  GraphqlLoadingEvent._();
 
-  GraphqlLoadingEvent({@required this.result});
+  factory GraphqlLoadingEvent({
+    @required QueryResult result,
+  }) = _GraphqlLoadingEvent<T>;
 }
 
-class GraphqlLoadedEvent<T> extends GraphqlEvent<T> {
-  final T data;
-  final QueryResult result;
+@freezed
+abstract class GraphqlLoadedEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlLoadedEvent<T> {
+  GraphqlLoadedEvent._();
 
-  GraphqlLoadedEvent({@required this.data, @required this.result});
+  factory GraphqlLoadedEvent({@required T data, @required QueryResult result}) =
+      _GraphqlLoadedEvent<T>;
 }
 
-class GraphqlRefetchEvent<T> extends GraphqlEvent<T> {}
+@freezed
+abstract class GraphqlRefetchEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlRefetchEvent<T> {
+  GraphqlRefetchEvent._();
+
+  factory GraphqlRefetchEvent() = _GraphqlRefetchEvent<T>;
+}
 
-class GraphqlFetchMoreEvent<T> extends GraphqlEvent<T> {
-  final FetchMoreOptions options;
+@freezed
+abstract class GraphqlFetchMoreEvent<T> extends GraphqlEvent<T>
+    implements _$GraphqlFetchMoreEvent<T> {
+  GraphqlFetchMoreEvent._();
 
-  GraphqlFetchMoreEvent({@required this.options});
+  factory GraphqlFetchMoreEvent({
+    @required FetchMoreOptions options,
+  }) = _GraphqlFetchMoreEvent<T>;
 }