Flutter Diagnosticable demonstration

main.dart

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark(),
      home: Scaffold(
        body: Center(
          child: MyWidget(
            diagnosticable: WithDiagnosticable(
              string: "string",
              integer: 1,
              color: Colors.red,
            ),
            notDiagnosticable: NotDiagnosticable(
              string: "string",
              integer: 1,
              color: Colors.red,
            ),
          ),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  final WithDiagnosticable diagnosticable;
  final NotDiagnosticable notDiagnosticable;

  const MyWidget({
    Key? key,
    required this.diagnosticable,
    required this.notDiagnosticable,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Text('Hello, World!', style: Theme.of(context).textTheme.headline4);
  }

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<WithDiagnosticable>(
        'diagnosticable', diagnosticable));
    DiagnosticsProperty<NotDiagnosticable>(
        'notDiagnosticable', notDiagnosticable);
  }
}

class WithDiagnosticable with Diagnosticable {
  final String string;
  final int integer;
  final Color color;

  WithDiagnosticable({
    required this.string,
    required this.integer,
    required this.color,
  });

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(StringProperty('string', string));
    properties.add(IntProperty('int', integer));
    properties.add(ColorProperty('color', color));
  }
}

class NotDiagnosticable {
  final String string;
  final int integer;
  final Color color;

  NotDiagnosticable({
    required this.string,
    required this.integer,
    required this.color,
  });
}