Create redux.dart

packages/signals_flutter/example/lib/examples/redux.dart

@@ -0,0 +1,144 @@
+import 'package:flutter/material.dart';
+import 'package:signals_flutter/signals_flutter.dart';
+
+sealed class AppAction {}
+
+class AddItemAction extends AppAction {
+  String item;
+  AddItemAction(this.item);
+}
+
+class UpdateItemAction extends AppAction {
+  int index;
+  String item;
+  UpdateItemAction(this.index, this.item);
+}
+
+class RemoveItemAction extends AppAction {
+  int index;
+  RemoveItemAction(this.index);
+}
+
+class PerformSearchAction extends AppAction {
+  String query;
+  PerformSearchAction(this.query);
+}
+
+@immutable
+class AppState {
+  final List<String> items;
+  final String searchQuery;
+
+  const AppState(this.items, this.searchQuery);
+}
+
+AppState reducer(AppState state, AppAction action) {
+  return switch (action) {
+    AddItemAction action => AppState(
+        List.from(state.items)..add(action.item),
+        state.searchQuery,
+      ),
+    RemoveItemAction action => AppState(
+        List.from(state.items)..removeAt(action.index),
+        state.searchQuery,
+      ),
+    UpdateItemAction action => AppState(
+        List.from(state.items)
+          ..[action.index] = action.item,
+        state.searchQuery,
+      ),
+    PerformSearchAction action => AppState(state.items, action.query),
+  };
+}
+
+class Store<T extends AppState, A extends AppAction> extends FlutterSignal<T> {
+  Store(this.reducer, super.internalValue);
+  final T Function(T state, A action) reducer;
+
+  void dispatch(A action) {
+    value = reducer(value, action);
+  }
+
+  T get state => value;
+}
+
+class AppStore extends Store<AppState, AppAction> {
+  AppStore() : super(reducer, const AppState([], ""));
+
+  late final items = select((v) => v.value.items);
+  late final searchQuery = select((v) => v.value.searchQuery);
+}
+
+void main() {
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      debugShowCheckedModeBanner: false,
+      theme: ThemeData.light(),
+      darkTheme: ThemeData.dark(),
+      home: const Example(),
+    );
+  }
+}
+
+class Example extends StatelessWidget {
+  const Example({
+    super.key,
+    this.title = 'Example',
+  });
+
+  final String title;
+
+  @override
+  Widget build(BuildContext context) {
+    return SignalProvider<AppStore>(
+      create: () => AppStore(),
+      child: Scaffold(
+        appBar: AppBar(
+          backgroundColor: Theme.of(context).colorScheme.inversePrimary,
+          title: Text(title),
+        ),
+        body: Builder(
+          builder: (context) {
+            final store = SignalProvider.of<AppStore>(context)!;
+            if (store.items.value.isEmpty) {
+              return const Center(child: Text('No items added'));
+            }
+            return ListView.builder(
+              itemCount: store.items.value.length,
+              itemBuilder: (context, index) {
+                final item = store.items.value[index];
+                return ListTile(
+                  key: ValueKey((store.items.value.length, index)),
+                  title: TextFormField(
+                    initialValue: item,
+                    onChanged: (val) => store.dispatch(UpdateItemAction(index, val)),
+                  ),
+                  trailing: IconButton(
+                    icon: const Icon(Icons.delete),
+                    onPressed: () => store.dispatch(RemoveItemAction(index)),
+                  ),
+                );
+              },
+            );
+          },
+        ),
+        floatingActionButton: Builder(builder: (context) {
+          final store = SignalProvider.of<AppStore>(context, listen: false)!;
+          return FloatingActionButton(
+            onPressed: () => store.dispatch(AddItemAction('New Item')),
+            tooltip: 'Add Item',
+            child: const Icon(Icons.add),
+          );
+        }),
+      ),
+    );
+  }
+}