text_editing_2.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
 @override
 Widget build(BuildContext context) => MaterialApp(
       title: 'Flutter TextField Key Binding Demo',
       home: Scaffold(body: UnforgivingTextField()),
     );
}
 
/// A text field that clears itself if the user tries to back up or correct
/// something.
class UnforgivingTextField extends StatefulWidget {
 @override
 State<UnforgivingTextField> createState() => _UnforgivingTextFieldState();
}
 
class _UnforgivingTextFieldState extends State<UnforgivingTextField> {
 // The text editing controller used to clear the text field.
 late TextEditingController controller;
 
 @override
 void initState() {
   super.initState();
   controller = TextEditingController();
 }
 
 @override
 Widget build(BuildContext context) => Shortcuts(
       shortcuts: <LogicalKeySet, Intent>{
         // This overrides the left arrow key binding that the text field normally
         // has in order to move the cursor back by a character. The default is
         // created by the MaterialApp, which has a DefaultTextEditingShortcuts
         // widget in it.
         LogicalKeySet(LogicalKeyboardKey.arrowLeft): const ClearIntent(),
 
         // This binds the delete and backspace keys to also clear the text field.
         // You can bind any key, not just those already bound in
         // DefaultTextEditingShortcuts.
         LogicalKeySet(LogicalKeyboardKey.delete): const ClearIntent(),
         LogicalKeySet(LogicalKeyboardKey.backspace): const ClearIntent(),
       },
       child: Actions(
         actions: <Type, Action<Intent>>{
           // This binds the intent that indicates clearing a text field to the
           // action that does the clearing.
           ClearIntent: ClearAction(controller: controller),
         },
         child: Center(child: TextField(controller: controller)),
       ),
     );
}
 
/// An intent that is bound to ClearAction.
class ClearIntent extends Intent {
 const ClearIntent();
}
 
/// An action that is bound to ClearIntent that clears the TextEditingController
/// passed to it.
class ClearAction extends Action<ClearIntent> {
 ClearAction({required this.controller});
 
 final TextEditingController controller;
 
 @override
 Object? invoke(covariant ClearIntent intent) {
   controller.clear();
 }
}