Unique ID

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_getx/my_controller.dart';
import 'package:flutter_getx/next_screen.dart';
import 'package:flutter_getx/student.dart';
import 'package:flutter_getx/unknown_route.dart';
import 'package:get/get.dart';
import 'home.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  MyController myController = Get.put(MyController());

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return GetMaterialApp(
      title: "State Management",
      home: Scaffold(
        appBar: AppBar(title: Text("State Management")),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              GetBuilder<MyController>(
                id: 'txtCount',
                builder: (controller) {
                  return Text(
                    "The value is  ${controller.count}",
                    style: TextStyle(fontSize: 25),
                  );
                },
              ),
              GetBuilder<MyController>(
                builder: (controller) {
                  return Text(
                    "The value is  ${controller.count}",
                    style: TextStyle(fontSize: 25),
                  );
                },
              ),
              SizedBox(
                height: 10,
              ),
              RaisedButton(
                child: Text("Increment"),
                onPressed: ()=>myController.increment(),
              )
            ],
          ),
        ),
      ),
    );
  }
}

my_controller.dart

import 'package:flutter_getx/student.dart';
import 'package:get/get.dart';

import 'home.dart';

class MyController extends GetxController {
  var count = 0;
  void increment()
  {
    count++;
    update(['txtCount']);
  }

}