How to Add two number in Flutter

This Flutter tutorial will teach you how to add two number.due to current techoligal demend we also created an app you friendly.The app is developed steps ahead of the existing world. While app development will be very useful for the future as well.

Main.dart

import 'package:addnumbers/addnumber.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: AddNumbers(),
    );
  }
}

addnumbers.dart

import 'package:flutter/material.dart';

class AddNumbers extends StatefulWidget 
{
  final TextEditingController controller; 
  const AddNumbers({ Key key, this.controller, }) : super(key: key);
  @override
  _AddNumbersState createState() => _AddNumbersState();
}
class _AddNumbersState extends State<AddNumbers> {
  @override
  Widget build(BuildContext context) 
  {
       var size = MediaQuery.of(context).size;
       final _num1 = TextEditingController();
       final _num2 = TextEditingController();
       final _tot = TextEditingController();
       int result;
       int sum;
       
    return Scaffold(
      body: SafeArea(
        child: Container(
           padding:EdgeInsets.symmetric(horizontal: 15,vertical: 20),
          child: Column(
            children: [
              Text("Add Two Numbers",style: TextStyle(fontSize: 30, color: Colors.black)),
               SizedBox(height: 15,),

              TextField(
                         controller: _num1,
                         decoration: InputDecoration(
                           labelText: "Number 1",
                           labelStyle: TextStyle(fontSize: 15,color: Colors.grey.shade400),
                           border: OutlineInputBorder(borderRadius: BorderRadius.circular(10))
                         ),
              ),
            SizedBox(height: 15,),
             TextField(
                 controller: _num2,
                      
                       decoration: InputDecoration(
                         labelText: "Number 2",
                         labelStyle: TextStyle(fontSize: 15,color: Colors.grey.shade400),
                         border: OutlineInputBorder(borderRadius: BorderRadius.circular(10))
                       ),
                     ),
            SizedBox(height: 15,),
             TextField(
                 controller: _tot,
                       decoration: InputDecoration(
                         labelText: "Total",
                         labelStyle: TextStyle(fontSize: 15,color: Colors.grey.shade400),
                         border: OutlineInputBorder(borderRadius: BorderRadius.circular(10))
                       ),
                     ),
            SizedBox(height: 15,),
           GestureDetector
             ( 
             onTap: ()
             {
                   sum = int.parse(_num1.text) + int.parse( _num2.text);
                   result = sum;
                   _tot.text = result.toString();
             },
             child: Container(
                alignment: Alignment.center,
                  height: size.height / 14,
                        width: size.width,
                       decoration: BoxDecoration(color: Colors.red,
                          borderRadius: BorderRadius.circular(5)),
                          child: Text("Add", 
                          style: TextStyle(color: Colors.white,
                          fontWeight: FontWeight.bold),),
                   ),
           ),
            ],
          ),      
        ),
      ),
    );
  }
}

I have attached the video tutorial below it will help you  to do this  step by step.