fix button "to top" to not use "useState()"

lib/views/home_page/bloc/bloc.dart

@@ -8,6 +8,17 @@ class HomeBloc extends Bloc<HomeEvent, HomeState> {
 
   HomeBloc(this.repo) : super(const HomeState()) {
     on<HomeLoadDataEvent>(_onLoadData);
+    on<HomeShowButtonToTopEvent>(_onShowButton);
+  }
+
+  void _onShowButton(HomeShowButtonToTopEvent event, Emitter<HomeState> emit) {
+    if (event.isShown != null) {
+      if (event.isShown == true) {
+        emit(state.copyWith(isButtonToTopShown: true));
+      } else {
+        emit(state.copyWith(isButtonToTopShown: false));
+      }
+    }
   }
 
   Future<void> _onLoadData(

lib/views/home_page/bloc/events.dart

@@ -9,3 +9,9 @@ class HomeLoadDataEvent extends HomeEvent {
 
   const HomeLoadDataEvent({this.search, this.nextPage, this.hasError});
 }
+
+class HomeShowButtonToTopEvent extends HomeEvent {
+  final bool? isShown;
+
+  const HomeShowButtonToTopEvent({this.isShown});
+}

lib/views/home_page/bloc/state.dart

@@ -9,14 +9,17 @@ class HomeState extends Equatable {
   final HomeData? data;
   final bool isLoading;
   final bool isPaginationLoading;
+  final bool isButtonToTopShown;
   final String? error;
 
   const HomeState(
       {this.data,
       this.isLoading = false,
       this.isPaginationLoading = false,
+      this.isButtonToTopShown = false,
       this.error});
 
   @override
-  List<Object?> get props => [data, isLoading, isPaginationLoading, error];
+  List<Object?> get props =>
+      [data, isLoading, isPaginationLoading, isButtonToTopShown, error];
 }

lib/views/home_page/bloc/state.g.dart

@@ -13,6 +13,8 @@ abstract class _$HomeStateCWProxy {
 
   HomeState isPaginationLoading(bool isPaginationLoading);
 
+  HomeState isButtonToTopShown(bool isButtonToTopShown);
+
   HomeState error(String? error);
 
   /// This function **does support** nullification of nullable fields. All `null` values passed to `non-nullable` fields will be ignored. You can also use `HomeState(...).copyWith.fieldName(...)` to override fields one at a time with nullification support.
@@ -25,6 +27,7 @@ abstract class _$HomeStateCWProxy {
     HomeData? data,
     bool? isLoading,
     bool? isPaginationLoading,
+    bool? isButtonToTopShown,
     String? error,
   });
 }
@@ -45,6 +48,10 @@ class _$HomeStateCWProxyImpl implements _$HomeStateCWProxy {
   HomeState isPaginationLoading(bool isPaginationLoading) =>
       this(isPaginationLoading: isPaginationLoading);
 
+  @override
+  HomeState isButtonToTopShown(bool isButtonToTopShown) =>
+      this(isButtonToTopShown: isButtonToTopShown);
+
   @override
   HomeState error(String? error) => this(error: error);
 
@@ -60,6 +67,7 @@ class _$HomeStateCWProxyImpl implements _$HomeStateCWProxy {
     Object? data = const $CopyWithPlaceholder(),
     Object? isLoading = const $CopyWithPlaceholder(),
     Object? isPaginationLoading = const $CopyWithPlaceholder(),
+    Object? isButtonToTopShown = const $CopyWithPlaceholder(),
     Object? error = const $CopyWithPlaceholder(),
   }) {
     return HomeState(
@@ -77,6 +85,11 @@ class _$HomeStateCWProxyImpl implements _$HomeStateCWProxy {
               ? _value.isPaginationLoading
               // ignore: cast_nullable_to_non_nullable
               : isPaginationLoading as bool,
+      isButtonToTopShown: isButtonToTopShown == const $CopyWithPlaceholder() ||
+              isButtonToTopShown == null
+          ? _value.isButtonToTopShown
+          // ignore: cast_nullable_to_non_nullable
+          : isButtonToTopShown as bool,
       error: error == const $CopyWithPlaceholder()
           ? _value.error
           // ignore: cast_nullable_to_non_nullable

lib/views/home_page/home_page.dart

@@ -24,9 +24,6 @@ class _HomePageState extends State<HomePage> {
   Widget build(BuildContext context) {
     return Scaffold(
         appBar: AppBar(
-          flexibleSpace: GestureDetector(
-            onTap: () => print("to top"),
-          ),
           backgroundColor: Theme.of(context).colorScheme.inversePrimary,
           title: Center(
             child: Text(
@@ -118,15 +115,17 @@ class _BodyState extends State<Body> {
                   : const SizedBox.shrink())
         ],
       ),
-      isButtonToTopShown
+      BlocBuilder<HomeBloc, HomeState>(
-          ? Container(
+        builder: (context, state) => state.isButtonToTopShown
-              alignment: Alignment.topRight,
+            ? Container(
-              padding: EdgeInsets.only(right: 16, top: 64),
+                alignment: Alignment.topRight,
-              child: FloatingActionButton(
+                padding: EdgeInsets.only(right: 16, top: 64),
-                onPressed: _goToTop,
+                child: FloatingActionButton(
-                child: Icon(Icons.arrow_upward_rounded),
+                  onPressed: _goToTop,
-              ))
+                  child: Icon(Icons.arrow_upward_rounded),
-          : SizedBox.shrink()
+                ))
+            : SizedBox.shrink(),
+      )
     ]);
   }
 
@@ -158,19 +157,16 @@ class _BodyState extends State<Body> {
   }
 
   void _viewListScrollListener() {
-    if (!isButtonToTopShown) {
+    if (!context.read<HomeBloc>().state.isButtonToTopShown) {
       if (scrollController.offset >= 400) {
-        setState(() {
+        context.read<HomeBloc>().add(HomeShowButtonToTopEvent(isShown: true));
-          isButtonToTopShown = true;
-        });
       }
     } else {
       if (scrollController.offset < 400) {
-        setState(() {
+        context.read<HomeBloc>().add(HomeShowButtonToTopEvent(isShown: false));
-          isButtonToTopShown = false;
-        });
       }
     }
+
     if (scrollController.offset >= scrollController.position.maxScrollExtent) {
       final bloc = context.read<HomeBloc>();