Added a bloc to validate the tier list name

lib/application/bloc.dart

@@ -18,6 +18,7 @@ export 'main_tab/main_tab_bloc.dart';
 export 'material/material_bloc.dart';
 export 'materials/materials_bloc.dart';
 export 'settings/settings_bloc.dart';
+export 'tier_list_form/tier_list_form_bloc.dart';
 export 'tierlist/tier_list_bloc.dart';
 export 'today_materials/today_materials_bloc.dart';
 export 'url_page/url_page_bloc.dart';

lib/application/tier_list_form/tier_list_form_bloc.dart

@@ -0,0 +1,33 @@
+import 'dart:async';
+
+import 'package:bloc/bloc.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:genshindb/domain/extensions/string_extensions.dart';
+import 'package:meta/meta.dart';
+
+part 'tier_list_form_bloc.freezed.dart';
+part 'tier_list_form_event.dart';
+part 'tier_list_form_state.dart';
+
+const _initialState = TierListFormState.loaded(name: '', isNameDirty: false, isNameValid: false);
+
+class TierListFormBloc extends Bloc<TierListFormEvent, TierListFormState> {
+  TierListFormBloc() : super(_initialState);
+
+  static int nameMaxLength = 25;
+
+  @override
+  Stream<TierListFormState> mapEventToState(TierListFormEvent event) async* {
+    final s = event.map(
+      nameChanged: (e) {
+        final isValid = e.name.isNotNullEmptyOrWhitespace && e.name.length <= nameMaxLength;
+        final isDirty = e.name != state.name;
+
+        return state.copyWith.call(name: e.name, isNameDirty: isDirty, isNameValid: isValid);
+      },
+      close: (_) => _initialState,
+    );
+
+    yield s;
+  }
+}

lib/application/tier_list_form/tier_list_form_event.dart

@@ -0,0 +1,10 @@
+part of 'tier_list_form_bloc.dart';
+
+@freezed
+abstract class TierListFormEvent implements _$TierListFormEvent {
+  const factory TierListFormEvent.nameChanged({
+    @required String name,
+  }) = _NameChanged;
+
+  const factory TierListFormEvent.close() = _Close;
+}

lib/application/tier_list_form/tier_list_form_state.dart

@@ -0,0 +1,10 @@
+part of 'tier_list_form_bloc.dart';
+
+@freezed
+abstract class TierListFormState implements _$TierListFormState {
+  const factory TierListFormState.loaded({
+    @required String name,
+    @required bool isNameDirty,
+    @required bool isNameValid,
+  }) = _LoadedState;
+}

lib/main.dart

@@ -200,6 +200,7 @@ class MyApp extends StatelessWidget {
             return CalculatorAscMaterialsOrderBloc(dataService, ctx.read<CalculatorAscMaterialsBloc>());
           },
         ),
+        BlocProvider(create: (_) => TierListFormBloc()),
       ],
       child: BlocBuilder<MainBloc, MainState>(
         builder: (ctx, state) => AppWidget(),

lib/presentation/tierlist/widgets/rename_tierlist_dialog.dart

@@ -19,11 +19,13 @@ class RenameTierListRowDialog extends StatefulWidget {
 
 class _RenameTierListRowDialogState extends State<RenameTierListRowDialog> {
   TextEditingController _textController;
+  String _currentValue;
 
   @override
   void initState() {
-    final text = widget.title ?? '';
-    _textController = TextEditingController(text: text);
+    _currentValue = widget.title;
+    _textController = TextEditingController(text: _currentValue);
+    _textController.addListener(_textChanged);
     super.initState();
   }
 
@@ -33,39 +35,54 @@ class _RenameTierListRowDialogState extends State<RenameTierListRowDialog> {
     return AlertDialog(
       title: Text(s.rename),
       actions: [
-        FlatButton(
-          onPressed: () {
-            Navigator.pop(context);
-          },
+        OutlinedButton(
+          onPressed: () => Navigator.pop(context),
           child: Text(s.cancel),
         ),
-        FlatButton(
-          onPressed: () {
-            context.read<TierListBloc>().add(TierListEvent.rowTextChanged(index: widget.index, newValue: _textController.text));
-            Navigator.pop(context);
-          },
-          child: Text(s.ok),
-        )
+        BlocBuilder<TierListFormBloc, TierListFormState>(
+          builder: (ctx, state) => ElevatedButton(
+            onPressed: state.isNameValid ? _saveName : null,
+            child: Text(s.save),
+          ),
+        ),
       ],
-      content: TextFormField(
-        controller: _textController,
-        keyboardType: TextInputType.text,
-        minLines: 1,
-        maxLength: 40,
-        autofocus: true,
-        textInputAction: TextInputAction.next,
-        decoration: InputDecoration(
-          alignLabelWithHint: true,
-          labelText: s.name,
-          hintText: s.tierListBuilder,
+      content: BlocBuilder<TierListFormBloc, TierListFormState>(
+        builder: (ctx, state) => TextFormField(
+          controller: _textController,
+          keyboardType: TextInputType.text,
+          minLines: 1,
+          maxLength: TierListFormBloc.nameMaxLength,
+          autofocus: true,
+          textInputAction: TextInputAction.next,
+          decoration: InputDecoration(
+            alignLabelWithHint: true,
+            labelText: s.name,
+            hintText: s.tierListBuilder,
+            errorText: !state.isNameValid && state.isNameDirty ? s.invalidValue : null,
+          ),
         ),
       ),
     );
   }
 
   @override
   void dispose() {
+    _textController.removeListener(_textChanged);
     _textController.dispose();
     super.dispose();
   }
+
+  void _saveName() {
+    context.read<TierListBloc>().add(TierListEvent.rowTextChanged(index: widget.index, newValue: _textController.text));
+    Navigator.pop(context);
+  }
+
+  void _textChanged() {
+    //Focusing the text field triggers text changed, that why we used it like this
+    if (_currentValue == _textController.text) {
+      return;
+    }
+    _currentValue = _textController.text;
+    context.read<TierListFormBloc>().add(TierListFormEvent.nameChanged(name: _currentValue));
+  }
 }

lib/presentation/tierlist/widgets/tierlist_row.dart

@@ -186,6 +186,7 @@ class TierListRow extends StatelessWidget {
         index: index,
       ),
     );
+    context.read<TierListFormBloc>().add(const TierListFormEvent.close());
   }
 
   Future<void> _showColorPicker(BuildContext context) async {