A lightweight, flexible Flutter widget for managing app initialisation with a customisable splash screen.

app_initializer.dart

class AppInitializer extends StatefulWidget {
  final Future Function() onAppInit;
  final Widget Function(BuildContext) splashBuilder;
  final Widget Function(BuildContext) appBuilder;

  const AppInitializer(
      {super.key,
      required this.splashBuilder,
      required this.appBuilder,
      required this.onAppInit});

  @override
  State<AppInitializer> createState() => _AppInitializerState();
}

class _AppInitializerState extends State<AppInitializer> {
  bool _initialized = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      if (!_initialized) {
        await widget.onAppInit();
        setState(() {
          _initialized = true;
        });
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return _initialized
        ? widget.appBuilder(context)
        : widget.splashBuilder(context);
  }
}