modern-app-patterns

Dependency Injection with get_it

Goal: Register and resolve dependencies without passing them through constructors everywhere.

Pattern

• Use get_it as a service locator.
• Register singletons/factories at app start.

Example

// di/config.dart
import 'package:dio/dio.dart';
import 'package:get_it/get_it.dart';

final sl = GetIt.instance;

void configureDi() {
  sl.registerLazySingleton(() => Dio(BaseOptions(baseUrl: 'https://example.com')));
  // sl.registerLazySingleton<TodosRepo>(() => TodosRepoDio(sl()));
}

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

void main() { configureDi(); runApp(const MyApp()); }
class MyApp extends StatelessWidget { const MyApp({super.key});
  @override Widget build(BuildContext context) => const MaterialApp(home: Scaffold(body: Center(child: Text('DI ready'))));
}

Notes

• Prefer explicit constructor injection in pure code; use locator at app boundary.

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Sandbox copy map

• Put di/ under sandboxes/flutter/lib/ and call configureDi() in main().
• Add get_it (and dio if used) to the sandbox pubspec.yaml.

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