adding packages

2026-01-15 14:38:46 -08:00
parent ef86e3ab6a
commit 6869cf47e5
5253 changed files with 726695 additions and 34 deletions
@@ -0,0 +1,100 @@
+import 'package:flutter/material.dart';
+
+import 'package:undo/undo.dart';
+
+void main() => runApp(MyApp());
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      theme: ThemeData.light(),
+      darkTheme: ThemeData.dark(),
+      debugShowCheckedModeBanner: false,
+      home: HomeScreen(),
+    );
+  }
+}
+
+class HomeScreen extends StatefulWidget {
+  @override
+  _HomeScreenState createState() => _HomeScreenState();
+}
+
+class _HomeScreenState extends State<HomeScreen> {
+  TrackedValueNotifier _controller = TrackedValueNotifier(0);
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder(
+      valueListenable: _controller,
+      builder: (context, count, child) => Scaffold(
+        appBar: AppBar(
+          title: Text('Undo/Redo Example'),
+        ),
+        body: Center(
+          child: Text('Count: $count'),
+        ),
+        bottomNavigationBar: BottomAppBar(
+          child: Row(
+            children: <Widget>[
+              IconButton(
+                icon: Icon(Icons.arrow_back),
+                onPressed: !_controller.canUndo
+                    ? null
+                    : () {
+                        if (mounted)
+                          setState(() {
+                            _controller.undo();
+                          });
+                      },
+              ),
+              IconButton(
+                icon: Icon(Icons.arrow_forward),
+                onPressed: !_controller.canRedo
+                    ? null
+                    : () {
+                        if (mounted)
+                          setState(() {
+                            _controller.redo();
+                          });
+                      },
+              ),
+            ],
+          ),
+        ),
+        floatingActionButtonLocation: FloatingActionButtonLocation.endDocked,
+        floatingActionButton: FloatingActionButton(
+          heroTag: ValueKey('add_button'),
+          child: Icon(Icons.add),
+          onPressed: () {
+            _controller.value = count + 1;
+          },
+        ),
+      ),
+    );
+  }
+}
+
+class TrackedValueNotifier<T> extends ValueNotifier<T> {
+  late SimpleStack<T> _simpleStack;
+
+  TrackedValueNotifier(T val, {int? limit}) : super(val) {
+    _simpleStack = SimpleStack<T>(val, limit: limit, onUpdate: (newVal) {
+      value = newVal;
+      notifyListeners();
+    });
+  }
+
+  @override
+  // ignore: avoid_return_types_on_setters
+  void set value(T newValue) {
+    _simpleStack.modify(newValue);
+    super.value = newValue;
+  }
+
+  bool get canUndo => _simpleStack.canUndo;
+  bool get canRedo => _simpleStack.canRedo;
+  void redo() => _simpleStack.redo();
+  void undo() => _simpleStack.undo();
+}