Add ValueTabController – generic feature!

web/slide_puzzle/lib/src/puzzle_home_state.dart

@@ -12,6 +12,7 @@ import 'flutter.dart';
 import 'puzzle_flow_delegate.dart';
 import 'shared_theme.dart';
 import 'themes.dart';
+import 'value_tab_controller.dart';
 
 class PuzzleHomeState extends State with TickerProviderStateMixin, AppState {
   @override
@@ -163,7 +164,8 @@ Widget _updateConstraints(
 Widget _doBuild(BuildContext _, BoxConstraints constraints) =>
     _updateConstraints(constraints, _doBuildCore);
 
-Widget _doBuildCore(bool small) => PuzzleThemeTabController(
+Widget _doBuildCore(bool small) => ValueTabController<SharedTheme>(
+      values: themes,
       child: Consumer<SharedTheme>(
         builder: (_, theme, __) => AnimatedContainer(
               duration: puzzleAnimationDuration,
@@ -190,8 +192,7 @@ Widget _doBuildCore(bool small) => PuzzleThemeTabController(
                                 margin:
                                     const EdgeInsets.symmetric(horizontal: 20),
                                 child: TabBar(
-                                  controller:
-                                      PuzzleThemeTabController.of(context),
+                                  controller: ValueTabController.of(context),
                                   labelPadding:
                                       const EdgeInsets.fromLTRB(0, 20, 0, 12),
                                   labelColor: theme.puzzleAccentColor,

web/slide_puzzle/lib/src/themes.dart

@@ -1,7 +1,3 @@
-import 'package:flutter_web/material.dart';
-import 'package:provider/provider.dart';
-
-import 'shared_theme.dart';
 import 'theme_plaster.dart';
 import 'theme_seattle.dart';
 import 'theme_simple.dart';
@@ -11,86 +7,3 @@ const themes = [
   ThemeSeattle(),
   ThemePlaster(),
 ];
-
-class PuzzleThemeTabController extends StatefulWidget {
-  /// Creates a default tab controller for the given [child] widget.
-  const PuzzleThemeTabController({
-    Key key,
-    @required this.child,
-  }) : super(key: key);
-
-  /// The widget below this widget in the tree.
-  ///
-  /// Typically a [Scaffold] whose [AppBar] includes a [TabBar].
-  ///
-  /// {@macro flutter.widgets.child}
-  final Widget child;
-
-  /// The closest instance of this class that encloses the given context.
-  ///
-  /// Typical usage:
-  ///
-  /// ```dart
-  /// TabController controller = DefaultTabBarController.of(context);
-  /// ```
-  static TabController of(BuildContext context) {
-    final scope =
-        context.inheritFromWidgetOfExactType(_PuzzleThemeTabControllerScope)
-            as _PuzzleThemeTabControllerScope;
-    return scope?.controller;
-  }
-
-  @override
-  _PuzzleThemeTabControllerState createState() =>
-      _PuzzleThemeTabControllerState();
-}
-
-class _PuzzleThemeTabControllerState extends State<PuzzleThemeTabController>
-    with SingleTickerProviderStateMixin {
-  final _notifier = ValueNotifier<SharedTheme>(themes.first);
-
-  TabController _controller;
-
-  @override
-  void initState() {
-    super.initState();
-    _controller = TabController(
-      vsync: this,
-      length: themes.length,
-      initialIndex: 0,
-    );
-
-    _controller.addListener(() {
-      _notifier.value = themes[_controller.index];
-    });
-  }
-
-  @override
-  void dispose() {
-    _controller.dispose();
-    super.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) => _PuzzleThemeTabControllerScope(
-        controller: _controller,
-        enabled: TickerMode.of(context),
-        child: ValueListenableProvider.value(
-          valueListenable: _notifier,
-          child: widget.child,
-        ),
-      );
-}
-
-class _PuzzleThemeTabControllerScope extends InheritedWidget {
-  const _PuzzleThemeTabControllerScope(
-      {Key key, this.controller, this.enabled, Widget child})
-      : super(key: key, child: child);
-
-  final TabController controller;
-  final bool enabled;
-
-  @override
-  bool updateShouldNotify(_PuzzleThemeTabControllerScope old) =>
-      enabled != old.enabled || controller != old.controller;
-}

web/slide_puzzle/lib/src/value_tab_controller.dart

@@ -0,0 +1,88 @@
+import 'package:flutter_web/material.dart';
+import 'package:provider/provider.dart';
+
+class ValueTabController<T> extends StatefulWidget {
+  /// Creates a default tab controller for the given [child] widget.
+  const ValueTabController({
+    Key key,
+    @required this.child,
+    @required this.values,
+  }) : super(key: key);
+
+  /// The widget below this widget in the tree.
+  ///
+  /// Typically a [Scaffold] whose [AppBar] includes a [TabBar].
+  ///
+  /// {@macro flutter.widgets.child}
+  final Widget child;
+
+  final List<T> values;
+
+  /// The closest instance of this class that encloses the given context.
+  ///
+  /// Typical usage:
+  ///
+  /// ```dart
+  /// TabController controller = DefaultTabBarController.of(context);
+  /// ```
+  static TabController of(BuildContext context) {
+    final scope = context.inheritFromWidgetOfExactType(_ValueTabControllerScope)
+        as _ValueTabControllerScope;
+    return scope?.controller;
+  }
+
+  @override
+  _ValueTabControllerState<T> createState() => _ValueTabControllerState<T>();
+}
+
+class _ValueTabControllerState<T> extends State<ValueTabController<T>>
+    with SingleTickerProviderStateMixin {
+  final _notifier = ValueNotifier<T>(null);
+
+  TabController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TabController(
+      vsync: this,
+      length: widget.values.length,
+      initialIndex: 0,
+    );
+
+    _notifier.value = widget.values.first;
+
+    _controller.addListener(() {
+      _notifier.value = widget.values[_controller.index];
+    });
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) => _ValueTabControllerScope(
+        controller: _controller,
+        enabled: TickerMode.of(context),
+        child: ValueListenableProvider.value(
+          valueListenable: _notifier,
+          child: widget.child,
+        ),
+      );
+}
+
+class _ValueTabControllerScope extends InheritedWidget {
+  const _ValueTabControllerScope(
+      {Key key, this.controller, this.enabled, Widget child})
+      : super(key: key, child: child);
+
+  final TabController controller;
+  final bool enabled;
+
+  @override
+  bool updateShouldNotify(_ValueTabControllerScope old) =>
+      enabled != old.enabled || controller != old.controller;
+}