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existing Actions widget using the Actions.of(context) method. Check whether
the action is enabled before calling invoke. Of course, you can also just call
invoke on the action itself, passing an Intent, but then you opt out of any
services that an action dispatcher might provide (like logging, undo/redo, and
so on).<topic_end>
<topic_start>
Action dispatchers
Most of the time, you just want to invoke an action, have it do its thing, and
forget about it. Sometimes, however, you might want to log the executed actions.This is where replacing the default ActionDispatcher with a custom dispatcher
comes in. You pass your ActionDispatcher to the Actions widget, and it
invokes actions from any Actions widgets below that one that doesn’t set a
dispatcher of its own.The first thing Actions does when invoking an action is look up the
ActionDispatcher and pass the action to it for invocation. If there is none,
it creates a default ActionDispatcher that simply invokes the action.If you want a log of all the actions invoked, however, you can create your own
LoggingActionDispatcher to do the job:
<code_start>class LoggingActionDispatcher extends ActionDispatcher {
@override
Object? invokeAction(
covariant Action<Intent> action,
covariant Intent intent, [
BuildContext? context,
]) {
print('Action invoked: $action($intent) from $context');
super.invokeAction(action, intent, context);
return null;
}
@override
(bool, Object?) invokeActionIfEnabled(
covariant Action<Intent> action,
covariant Intent intent, [
BuildContext? context,
]) {
print('Action invoked: $action($intent) from $context');
return super.invokeActionIfEnabled(action, intent, context);
}
}<code_end>
Then you pass that to your top-level Actions widget:
<code_start>@override
Widget build(BuildContext context) {
return Actions(
dispatcher: LoggingActionDispatcher(),
actions: <Type, Action<Intent>>{
SelectAllIntent: SelectAllAction(model),
},
child: Builder(
builder: (context) => TextButton(
onPressed: Actions.handler<SelectAllIntent>(
context,
const SelectAllIntent(),
),
child: const Text('SELECT ALL'),
),
),
);
}<code_end>
This logs every action as it executes, like so:<topic_end>
<topic_start>
Putting it together
The combination of Actions and Shortcuts is powerful: you can define generic
intents that map to specific actions at the widget level. Here’s a simple app
that illustrates the concepts described above. The app creates a text field that
also has “select all” and “copy to clipboard” buttons next to it. The buttons
invoke actions to accomplish their work. All the invoked actions and
shortcuts are logged.
<code_start>import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
/// A text field that also has buttons to select all the text and copy the
/// selected text to the clipboard.
class CopyableTextField extends StatefulWidget {
const CopyableTextField({super.key, required this.title});
final String title;
@override
State<CopyableTextField> createState() => _CopyableTextFieldState();
}
class _CopyableTextFieldState extends State<CopyableTextField> {
late final TextEditingController controller = TextEditingController();
@override
void dispose() {
controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Actions(
dispatcher: LoggingActionDispatcher(),
actions: <Type, Action<Intent>>{
ClearIntent: ClearAction(controller),
CopyIntent: CopyAction(controller),
SelectAllIntent: SelectAllAction(controller),
},
child: Builder(builder: (context) {
return Scaffold(
body: Center(
child: Row(
children: <Widget>[
const Spacer(),
Expanded(
child: TextField(controller: controller),
),
IconButton(