default app error catching in flutter sdk

main.dart

import 'package:flutter/material.dart';
import 'dart:ui';

class MyErrorsHandler {
  Future<void> initialize() async {
    debugPrint('initialize');
    // do some initialization 
  }

  void onErrorDetails(FlutterErrorDetails details) {
    debugPrint('onErrorDetails');
    debugPrint(details.toString());
  }

  void onError(Object error, StackTrace stack) {
    debugPrint('onError');
    debugPrint(error.toString());
    debugPrint(stack.toString());
  }
}

// Since flutter 3.3 or so we no longer
// use separate zones to accomplish this as 
// we are using platform dispatcher instead.
Future<void> main() async {
  await myErrorsHandler.initialize();
  FlutterError.onError = (details) {
    FlutterError.presentError(details);
    myErrorsHandler.onErrorDetails(details);
  };
  PlatformDispatcher.instance.onError = (error, stack) {
    myErrorsHandler.onError(error, stack);
    return true;
  };
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      builder: (context, widget) {
        Widget error = const Text('...rendering error...');
        if (widget is Scaffold || widget is Navigator) {
          error = Scaffold(body: Center(child: error));
        }
        ErrorWidget.builder = (errorDetails) => error;
        if (widget != null) return widget;
        throw ('widget is null');
      },
    );
  }
}

Article is at https://open.substack.com/pub/fredgrott/p/better-app-exceptions-catching-than?r=26egx&utm_campaign=post&utm_medium=web