42. Stateless e Stateful - Daniel Ciolfi - Curso Flutter

main.dart

/*
Rode na web
https://dartpad.dev/078f00a6e5d75c252eaa9a4177c1aa05

*/

import 'package:flutter/material.dart';


/* 001 
void main() {
  runApp(MaterialApp(
    title:  "Contador de Pessoas",
    home: Container(
      color: Colors.white,
    ) 
  )); //MyApp()
}
*/

//002 - Layout, StateLess -> StateFull
void main() {
  runApp(MaterialApp(title: "Contador de Pessoas", home: Home())); //MyApp()
}

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  int _people = 0;
  
  String _infoText = "Pode Entrar!";

  void _changePeople(int delta) {
    setState(() {
      _people += delta;
      
      if(_people < 0)
        _infoText = "Mundo Invertido";
      else if(_people <= 10) 
        _infoText = "Pode Entrar";
      else 
        _infoText = "Lotado!";      
      
    });
  }

  @override
  Widget build(BuildContext context) {
    return Stack(children: <Widget>[
      Container(color: Colors.grey), //troquei para Container pois não sei neste momento importar uma imagem da web
      Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text("Pessoas: $_people",
              style:
                  TextStyle(color: Colors.white, fontWeight: FontWeight.bold)),
          Row(mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[
            Padding(
              padding: EdgeInsets.all(10.0),
              child: FlatButton(
                child: Text("+1",
                    style: TextStyle(color: Colors.white, fontSize: 40)),
                onPressed: () {
                  debugPrint("+1");
                  _changePeople(1);
                },
              ),
            ),
            Padding(
              padding: EdgeInsets.all(10.0),
              child: FlatButton(
                child: Text("-1",
                    style: TextStyle(color: Colors.white, fontSize: 40)),
                onPressed: () {
                  _changePeople(-1);
                },
              ),
            )
          ]),
          Text("$_infoText",
              style: TextStyle(
                  color: Colors.white,
                  fontStyle: FontStyle.italic,
                  fontSize: 30)),
        ],
      )
    ]);
  }
}

/*
Padrao dartpad.dev

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Text('Hello, World!', style: Theme.of(context).textTheme.display1);
  }
}
*/