adaptive theme switcher example

adaptive_theme_switcher.dart

import 'package:adaptive_theme/adaptive_theme.dart';
import 'package:flutter/material.dart';

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

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

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return AdaptiveTheme(
      initial: AdaptiveThemeMode.light,
      light: ThemeData(
        brightness: Brightness.light,
        backgroundColor: Colors.white,
        primaryColor: Colors.black,
      ),
      dark: ThemeData(
        brightness: Brightness.dark,
        backgroundColor: Colors.black,
        primaryColor: Colors.white,
      ),
      builder: (light, dark) => MaterialApp(
        title: 'Flutter Demo',
        darkTheme: dark,
        theme: light,
        home: PageSwitcher(),
      ),
    );
  }
}

class PageSwitcher extends StatefulWidget {
  PageSwitcher({Key key}) : super(key: key);

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

class _PageSwitcherState extends State<PageSwitcher> {
  final List<Widget> pages = [Page1(), Page2(), Page3()];
  int currentPage = 0;

  void _setPage(int newPage) {
    if (currentPage != newPage)
      setState(() {
        currentPage = newPage;
      });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: pages[currentPage],
      bottomNavigationBar: BottomNavigationBar(
        selectedItemColor: Colors.amber[800],
        currentIndex: currentPage,
        onTap: _setPage,
        backgroundColor: Theme.of(context).backgroundColor,
        unselectedItemColor: Theme.of(context).primaryColor,
        items: [
          BottomNavigationBarItem(
            label: 'Page 1',
            icon: Icon(
              Icons.bar_chart,
            ),
          ),
          BottomNavigationBarItem(
            label: 'Page 2',
            icon: Icon(
              Icons.multiple_stop,
            ),
          ),
          BottomNavigationBarItem(
            label: 'Page 3',
            icon: Icon(
              Icons.attach_money,
            ),
          ),
        ],
      ),
    );
  }
}

class Page1 extends StatelessWidget {
  const Page1({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        backgroundColor: Theme.of(context).backgroundColor,
        appBar: AppBar(
          brightness: Theme.of(context).brightness,
          title: Text(
            'Page #1',
            style: TextStyle(
              color: Theme.of(context).primaryColor,
            ),
          ),
          backgroundColor: Theme.of(context).backgroundColor,
        ),
        body: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Text(
              'Page #1 content',
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Theme.of(context).primaryColor,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class Page2 extends StatelessWidget {
  const Page2({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Theme.of(context).backgroundColor,
      appBar: AppBar(
        brightness: Theme.of(context).brightness,
        title: Text(
          'Page #2',
          style: TextStyle(
            color: Theme.of(context).primaryColor,
          ),
        ),
        backgroundColor: Theme.of(context).backgroundColor,
        actions: [
          IconButton(
            icon: Icon(
              Icons.language,
            ),
            color: Theme.of(context).primaryColor,
            onPressed: () {},
          ),
          IconButton(
            icon: Icon(Icons.opacity),
            color: Theme.of(context).primaryColor,
            onPressed: () => AdaptiveTheme.of(context).toggleThemeMode(),
          ),
        ],
      ),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Text(
            'Page #2 content',
            textAlign: TextAlign.center,
            style: TextStyle(
              color: Theme.of(context).primaryColor,
            ),
          ),
        ],
      ),
    );
  }
}

class Page3 extends StatelessWidget {
  const Page3({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Theme.of(context).backgroundColor,
      appBar: AppBar(
        brightness: Theme.of(context).brightness,
        title: Text(
          'Page #3',
          style: TextStyle(
            color: Theme.of(context).primaryColor,
          ),
        ),
        backgroundColor: Theme.of(context).backgroundColor,
      ),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Text(
            'Page #3 content',
            textAlign: TextAlign.center,
            style: TextStyle(
              color: Theme.of(context).primaryColor,
            ),
          ),
        ],
      ),
    );
  }
}