import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  var usernameCtr = TextEditingController();
  var passwordCtr = TextEditingController();

  int angka;

  @override
  void initState() {
    super.initState();
    angka = int.parse(usernameCtr.text) + int.parse(passwordCtr.text);
  }

  Widget build(BuildContext context) {
    return MaterialApp(
      home: SafeArea(
          child: Scaffold(
        body: SingleChildScrollView(
          child: Column(children: <Widget>[
            TextFormField(
              controller: usernameCtr,
              decoration: InputDecoration(labelText: "Username"),
            ),
            TextFormField(
              controller: passwordCtr,
              decoration: InputDecoration(labelText: "Password"),
              keyboardType: TextInputType.number,
            ),
            const SizedBox(height: 30),
            InkWell(
              child: Container(
                width: 30,
                height: 30,
                decoration: BoxDecoration(
                    gradient: LinearGradient(
                        colors: [Color(4279757529), Color(0xFF6078ea)]),
                    borderRadius: BorderRadius.circular(6.0),
                    boxShadow: [
                      BoxShadow(
                          color: Color(0xFF6078ea).withOpacity(.3),
                          offset: Offset(0.0, 8.0),
                          blurRadius: 8.0)
                    ]),
                child: Material(
                  color: Colors.transparent,
                  child: InkWell(
                    onTap: () {
                      print(angka);
                      //teks=passwordCtr.text;
                      setState(() {});
                    },
                    child: Center(
                      child: Text("+",
                          style: TextStyle(
                              color: Colors.white,
                              fontSize: 18,
                              letterSpacing: 1.0)),
                    ),
                  ),
                ),
              ),
            ),
            Text(angka.toString())
          ]),
        ),
      )),
    );
  }
}