Building an Effective Error Handling System in Flutter with Custom Widgets

Problem: 

"NoSuch method error [] the method was called on null Reciver:null Tried calling []("Product") Also see docs http//flutter.dev/docs/testing/errors"?

Solution:

In Flutter, an error widget is a built-in widget that is display error message  when an error occurs in your app. However, the default error widget provided by Flutter may not always be good for all apps, and developers may need to create custom error message widgets that match the design and layout of their app. In this blog, we will discuss how to design an error message widget for Flutter using Dart programming language.

Step 1: Create A Custom Error Widget:

The initial step in crafting an error widget for Flutter is to generate a customized widget that appears when an error arises. To accomplish this, we establish a new Dart file and define a bespoke class that extends StatelessWidget. For instance, we could formulate a class named CustomErrorWidget:

class CustomErrorWidget extends StatelessWidget { final String errorMessage; CustomErrorWidget({this.errorMessage}); @override Widget build(BuildContext context) { return Center( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Icon( Icons.error_outline, color: Colors.red, size: 50.0, ), SizedBox(height: 10.0), Text( 'Error Occurred!', style: TextStyle(fontSize: 18.0, fontWeight: FontWeight.bold), ), SizedBox(height: 10.0), Text( errorMessage, textAlign: TextAlign.center, style: TextStyle(fontSize: 16.0), ), ], ), ); } }

In this example, we have created a custom widget that displays an error icon, a heading, and a message. We have also passed the error message as a parameter to the widget.

Step 2: Handle Errors:

Next, we need to handle errors within our app using the ErrorWidget. This widget catches any uncaught errors that occur within our app and displays the custom error widget instead. We can do this by wrapping our MaterialApp widget in a custom error handler that catches any uncaught errors and displays the custom error widget instead.

void main() { FlutterError.onError = (FlutterErrorDetails details) { FlutterError.dumpErrorToConsole(details); runApp(ErrorWidgetClass(details)); }; runApp(MyApp()); } class ErrorWidgetClass extends StatelessWidget { final FlutterErrorDetails errorDetails; ErrorWidgetClass(this.errorDetails); @override Widget build(BuildContext context) { return CustomErrorWidget( errorMessage: errorDetails.exceptionAsString(), ); } } class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Custom Error Widget Example', home: MyHomePage(), ); } } class MyHomePage extends StatelessWidget { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text('Custom Error Widget Example'), ), body: Center( child: ElevatedButton( child: Text('Throw Error'), onPressed: () { throw Exception('An error has occurred!'); }, ), ), ); } }

In this example, we have created a custom error handler that catches any uncaught errors and displays the custom error widget instead. We have also added a button that throws an exception when pressed, causing the custom error widget to be displayed.

Step 3: Run the App

Finally, we can run the app and test our custom error widget. When an error occurs, our custom error widget will be displayed instead of the default error widget provided by Flutter.

In conclusion, designing a custom error widget in Flutter using the Dart programming language is a simple process. By following these steps, we can create a custom error widget that matches the design and layout of our app and provides a better user experience when errors occur.