view_viewmodel.dart

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

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

 @override
 Widget build(BuildContext context) {
   // we have to wrap our widget inside a ViewModelBuilder 
   // to react to our viewmodel this implementation utilises 
   // Provider library behind the scenes
   return ViewModelBuilder<MyViewModel>.reactive(
     onModelReady: (model) => model.onModelReady(),
     builder: (context, model, child) => Scaffold(
      // add your content here, 
      // thanks to the model valriable 
      // received as parameter, you can 
      // interact with the viewmodel calling 
      // functions and listenting its variables
      body: Text(model.someText),
     ),
     viewModelBuilder: () => MyViewModel(),
   );
 }
}


import 'package:stacked/stacked.dart';

class MyViewModel extends BaseViewModel {
  
  String _someText = 'Hello World';
  String getSomeText => _someText;

  onModelReady() {
    // Do something here as initState
  }
  
  someRandomFunctionToUpdateUI() {
    // you can also update the UI just like calling
    // setState(...) by calling notifyListeners() 
    // as we do with Provider library
    _someText = 'Updates the UI!';
    notifyListeners();
  }
}