main.dart

import 'package:flutter/material.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 {
  var student = Student();

  // For making the entire class observable
  //final  student=Student( name:"tom",age:25).obs;
  @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: [
              Obx(() => Text(
                    "Name  is ${student.name.value}",
                    style: TextStyle(fontSize: 25),
                  )),
              SizedBox(
                height: 16,
              ),
              RaisedButton(
                child: Text("Upper"),
                onPressed: () {
                  //If individual variables are observable
                  student.name.value = student.name.value.toUpperCase();

                  // If entire class is observable
                  // student.update((student) {
                  //   student.name=student.name.toString().toUpperCase();
                  // });
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}

student.dart

import 'package:get/get.dart';

class Student {
  /* Classes can be made observable by making individuals variables Rx
  or by making the entire class observable.
   */
  // Individuals variables Rx
  var name = "Tom".obs;
  var age = 25.obs;

// To make the entire class observable
// var name;
// var age;
// Student({this.name, this.age});
}