Flutter: How can I prevent default behaviour on key press?

I've faced a similar problem and what to share how I solved it.

To stop the propagation we have to return true from onKey method of a FocusNode in the focus nodes tree. To achieve this I've wrapped my app body with FocusScope and Focus widgets like this:

MaterialApp(      home: Scaffold(          body: FocusScope(              autofocus: true,              child: Focus(                  autofocus: true,                  canRequestFocus: true,                  onKey: (data, event) {                    if (event.isKeyPressed(LogicalKeyboardKey.audioVolumeUp)) {                      print("Volume up");                      return true;                    }                    if (event                        .isKeyPressed(LogicalKeyboardKey.audioVolumeDown)) {                      print("Volume down");                      return true;                    }                    return false;                  },                  child: Text(text: "Hallochen")))))

Thanks to Sergey's answer I was able to solve the issue as well. In my case, I wanted to create a ListView, with pull to refresh (RefreshIndicator) that will work for both mobile devices and web.

I tried to implement a refresh indicator which will appear when the user clicks F5 to refresh the web page, but I had to prevent the browser from actually refreshing the page.

Here's an example of my implementation, which prevents refresh from occuring when the user clicks F5.

import 'package:flutter/material.dart';import 'package:flutter/services.dart';class ExamplePage extends StatefulWidget {  @override  _ExamplePageState createState() => _ExamplePageState();}class _ExamplePageState extends State<ExamplePage> {  final GlobalKey<AnimatedListState> listKey = GlobalKey<AnimatedListState>();  final GlobalKey<RefreshIndicatorState> _refreshIndicatorKey = new GlobalKey<RefreshIndicatorState>();    List items = [];  Future<void> _pullRefresh() async {    await Future.delayed(Duration(milliseconds: 1000));  }    @override  Widget build(BuildContext context) {    return FocusScope(      autofocus: true,      child: Focus(        autofocus: true,        canRequestFocus: true,        onKey: (data, event) {          if (event              .isKeyPressed(LogicalKeyboardKey.f5)) {            _refreshIndicatorKey.currentState!.show();            return KeyEventResult.handled;          }          return KeyEventResult.ignored;        },        child: Container(            padding: EdgeInsets.all(15.0),            child: RefreshIndicator(              key: _refreshIndicatorKey,              onRefresh: _pullRefresh,              child: AnimatedList(                key: listKey,                initialItemCount: items.length,                itemBuilder: (context, index, animation) {                  return _buildItem(context, index, animation);                },              ),            ),        ),      ),    );  }      Widget _buildItem(      BuildContext context, int index, Animation<double> animation) {    return Text("Example");    }}