GetMaterialApp on exit code example

Example 1: getx flutter

// Create controller class and extends GetxController
class Controller extends GetxController {
  int counter = 0;
  void increment() {
    counter++;
    update(); // use update() to update counter variable on UI when increment be called
  }
}
// On your Stateless/Stateful class, use GetBuilder to update Text when increment be called 
GetBuilder<Controller>(
  init: Controller(), // INIT IT ONLY THE FIRST TIME
  builder: (_) => Text(
    '${_.counter}',
  ),
)
//Initialize your controller only the first time. The second time you are using ReBuilder for the same controller, do not use it again. Your controller will be automatically removed from memory as soon as the widget that marked it as 'init' is deployed. You don't have to worry about that, Get will do it automatically, just make sure you don't start the same controller twice.

Example 2: get package flutter

class Home extends StatelessWidget {
  final controller = Get.put(Controller());
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("counter")),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            GetBuilder<Controller>(
                builder: (_) => Text(
                      'clicks: ${controller.count}',
                    )),
            RaisedButton(
              child: Text('Next Route'),
              onPressed: () {
                Get.to(Second());
              },
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
          child: Icon(Icons.add),
          onPressed: controller.increment(),  
          ),
    );
  }
}
class Second extends StatelessWidget {
  final Controller ctrl = Get.find();
  @override
  Widget build(context){
     return Scaffold(body: Center(child: Text("${ctrl.count}")));
  }
}