(Flutter)bottomNavigationBar 기본뼈대

-test.dart(메인)-

import 'package:flutter/material.dart';

import 'first.dart';
import 'home.dart';
import 'second.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  int _currentIndex = 0;
  final List<Widget> _children = [Home(), First(), Second()];

  //홈 화면 증가값
  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  //bottomNavigation 창 전환
  void _onTap(int index) {
    setState(() {
      _currentIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: _children[_currentIndex],
       /* body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                'You have pushed the button this many times:',
              ),
              Text(
                '$_counter',
                style: Theme.of(context).textTheme.display1,
              ),
            ],
          ),
        ),*/
        floatingActionButton: FloatingActionButton(
          onPressed: _incrementCounter,
          tooltip: 'Increment',
          child: Icon(Icons.add),
        ),
        // 추가된 bottomNavigationBar
        bottomNavigationBar: BottomNavigationBar(
            type: BottomNavigationBarType.fixed,
            onTap: (index) => _onTap(index),
            currentIndex: 0,
            items: [
              new BottomNavigationBarItem(
                icon: Icon(Icons.home),
                title: Text('Home'),
              ),
              new BottomNavigationBarItem(
                icon: Icon(Icons.mail),
                title: Text('First'),
              ),
              new BottomNavigationBarItem(
                icon: Icon(Icons.person),
                title: Text('Second'),
              )
            ]));
  }
}

-home.dart-

import 'package:flutter/material.dart';

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

class _HomeState extends State<Home> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
    );
  }
}

 

-first.dart-

import 'package:flutter/cupertino.dart';

class First extends StatefulWidget {
  @override
  _FirstState createState() => _FirstState();
}

class _FirstState extends State<First> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('first'),
    );
  }
}

-second.dart-

import 'package:flutter/cupertino.dart';

class Second extends StatefulWidget {
  @override
  _SecondState createState() => _SecondState();
}

class _SecondState extends State<Second> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('Second'),
    );
  }
}