belajar state

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String message = '';
  TextEditingController txtUsername = TextEditingController();
  TextEditingController txtPassword = TextEditingController();
  int rating = 0;

  void login() {
    // ambil username
    String user = txtUsername.text;
    // ambil password
    String pass = txtPassword.text;
    // cek jika username = 'admin' dan password = '1234' maka
    if (user == 'admin' && pass == '1234') {
      setState(() {
        message = 'Login Berhasil';
      });
    } else {
      setState(() {
        message = 'Login Gagal';
      });
    }
    // message = 'Login Berhasil'
    // selain itu message = 'Login Gagal'
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Belajar State')),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            children: [
              TextFormField(
                decoration: InputDecoration(hintText: 'Username'),
                controller: txtUsername,
              ),
              TextFormField(
                decoration: InputDecoration(hintText: 'Password'),
                obscureText: true,
                controller: txtPassword,
              ),
              SizedBox(height: 20),
              MyButton(title: 'Login', icon: Icons.login, myFunction: login),
              MyButton(title: 'Register', icon: Icons.app_registration),
              SizedBox(height: 20),
              Text(message),
              Image.network(
                'https://img.freepik.com/free-psd/modern-car-isolated_23-2151504546.jpg?semt=ais_incoming&w=740&q=80',
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: List.generate(5, (index) {
                  return IconButton(
                    onPressed: () {
                      setState(() {
                        rating = index + 1;
                      });
                    },
                    icon: Icon(
                      index < rating ? Icons.star : Icons.star_border_outlined,
                      color: Colors.red,
                    ),
                  );
                }),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class MyButton extends StatelessWidget {
  String title;
  Function()? myFunction;
  IconData? icon;
  MyButton({super.key, required this.title, this.myFunction, this.icon});

  @override
  Widget build(BuildContext context) {
    return TextButton(
      onPressed: () {
        myFunction!.call();
      },
      child: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(icon, color: Colors.blue),
          Text(title, style: TextStyle(color: Colors.blue, fontSize: 20)),
        ],
      ),
    );
  }
}