An action manager for saving executed changes that allows redoing and undoing of changes occured.
dependencies:
history_manager: 0.1.0
dependency_overrides:
history_manager:
git: https://github.com/rynssnjn/history_manager.gitInitializing the controller.
import 'package:history_manager/history_manager.dart';
HistoryController controller = new HistoryController();Creating a simple model by extending to ExecutedChange wherein it accepts different types.
class IncrementChange extends ExecutedChange<int> {
IncrementChange({
this.oldValue,
this.onExecute,
this.onUndo,
});
@override
final int oldValue;
@override
final VoidCallback onExecute;
@override
final OnUndoChange<int> onUndo;
}Adding a new executed change.
var counter = 0;
controller.add(IncrementChange(
oldValue: counter,
onExecute: () => counter++,
onUndo: (c) => counter = c,
));Checking if there is an undoable or a redoable changes.
controller.canUndo; // checks if there is an undoable change
controller.canRedo; // checks if there is a redoable change.Undoing the change from the last executed change.
print(counter); // 1
controller.undo();
print(counter); // 0Redoing the last undone change.
print(counter); // 0
controller.redo();
print(counter); // 1class IncrementNumbers extends StatefulWidget {
const IncrementNumbers({
Key key,
@required this.title,
}) : super(key: key);
final String title;
@override
State<IncrementNumbers> createState() => _IncrementNumbersState();
}
class _IncrementNumbersState extends State<IncrementNumbers> {
int _counter = 0;
HistoryController controller;
void _incrementCounter() {
controller.add(IncrementChange(
oldValue: _counter,
onExecute: () => setState(() => _counter++),
onUndo: (lastValue) => setState(() => _counter = lastValue),
));
}
@override
void initState() {
controller = HistoryController();
super.initState();
}
@override
void dispose() {
controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(widget.title)),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('Current count:'),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
CommonHistoryTools(
onUndo: controller.undo,
onRedo: controller.redo,
canUndo: controller.canUndo,
canRedo: controller.canRedo,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}
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