Using ErrorWidget in Flutter

In Flutter, the ErrorWidget widget is used to render an error message when a build method falls. You can easily implement an ErrorWidget by adding ErrorWidget.builder to the main() function like this:

void main() {
  ErrorWidget.builder = (FlutterErrorDetails details) {
    return <your widget>;
  };

  return runApp(MyApp());
}

For more clarity, please see the example below.

Example

In this example, we’ll create a fake error by doing this:

@override
void initState() {
    super.initState();
    throw ("Hi there. I am an error");
}

Screenshots

Without WidgetError, you’ll see a red screen with yellow text when the error occurs. By using WidgetError, you can display anything you want when your Flutter app runs into a problem:

The console will display additional information about the error as default.

The complete code:

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

void main() {
  ErrorWidget.builder = (FlutterErrorDetails details) {
    return Material(
      child: Container(
        color: Colors.purple,
        alignment: Alignment.center,
        child: const Text(
          'Something went wrong!',
          style: TextStyle(fontSize: 20, color: Colors.white),
        ),
      ),
    );
  };

  return runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      // Remove the debug banner
      debugShowCheckedModeBanner: false,
      title: 'Kindacode.com',
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  void initState() {
    super.initState();
    // throw a custom error
    throw ("Hi there. I am an error");
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: const Text('Kindacode.com'),
        ),
        body: const Center());
  }
}

Afterword

We’ve created a small app that demonstrates an elegant way to handle errors in Flutter. At this point, you should have a better understanding of the ErrorWidget. If you’d like to explore more new and interesting stuff about Flutter and Dart, take a look at the following articles:

• How to make an image carousel in Flutter
• How to implement Star Rating in Flutter
• Flutter: Making a Tic Tac Toe Game from Scratch
• Flutter & SQLite: CRUD Example
• Flutter and Firestore Database: CRUD example
• Flutter: CupertinoPicker Example

You can also check out our Flutter category page or Dart category page for the latest tutorials and examples.