//
// example of changing dark/light theme using hive
//
////////////////main.dart////////////////////////
import 'package:flutter/material.dart';
import 'package:hive/hive.dart';
import 'package:hive_flutter/hive_flutter.dart';

import './app_theme.dart';
import './home.dart';

const darkModeBox = 'darkModeTutorial';

void main() async {
  await Hive.initFlutter();
  await Hive.openBox(darkModeBox);
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder(
      valueListenable: Hive.box(darkModeBox).listenable(),
      builder: (context, box, widget) {
        var darkMode = box.get('darkMode', defaultValue: false);
        return MaterialApp(
          theme: AppTheme.lightTheme,
          darkTheme: AppTheme.darkTheme,
          themeMode: darkMode ? ThemeMode.dark : ThemeMode.light,
          home: Home(),
        );
      },
    );
  }
}
//////////////////app_theme.dart//////////////////////////////
import 'package:flutter/material.dart';

class AppTheme {
  AppTheme._();

  static Color _iconColor = Colors.blueAccent.shade200;

  static const Color _lightPrimaryColor = Colors.white;
  static const Color _lightPrimaryVariantColor = Color(0XFFE1E1E1);
  static const Color _lightSecondaryColor = Colors.green;
  static const Color _lightOnPrimaryColor = Colors.black;

  static const Color _darkPrimaryColor = Colors.white24;
  static const Color _darkPrimaryVariantColor = Colors.black;
  static const Color _darkSecondaryColor = Colors.white;
  static const Color _darkOnPrimaryColor = Colors.white;

  static final ThemeData lightTheme = ThemeData(
    scaffoldBackgroundColor: _lightPrimaryVariantColor,
    appBarTheme: AppBarTheme(
      color: _lightPrimaryVariantColor,
      iconTheme: IconThemeData(color: _lightOnPrimaryColor),
    ),
    colorScheme: ColorScheme.light(
      primary: _lightPrimaryColor,
      primaryVariant: _lightPrimaryVariantColor,
      secondary: _lightSecondaryColor,
      onPrimary: _lightOnPrimaryColor,
    ),
    iconTheme: IconThemeData(
      color: _iconColor,
    ),
    textTheme: _lightTextTheme,
  );

  static final ThemeData darkTheme = ThemeData(
    scaffoldBackgroundColor: _darkPrimaryVariantColor,
    appBarTheme: AppBarTheme(
      color: _darkPrimaryVariantColor,
      iconTheme: IconThemeData(color: _darkOnPrimaryColor),
    ),
    colorScheme: ColorScheme.light(
      primary: _darkPrimaryColor,
      primaryVariant: _darkPrimaryVariantColor,
      secondary: _darkSecondaryColor,
      onPrimary: _darkOnPrimaryColor,
    ),
    iconTheme: IconThemeData(
      color: _iconColor,
    ),
    textTheme: _darkTextTheme,
  );

  static final TextTheme _lightTextTheme = TextTheme(
    headline: _lightScreenHeadingTextStyle,
    body1: _lightScreenTaskNameTextStyle,
    body2: _lightScreenTaskDurationTextStyle,
  );

  static final TextTheme _darkTextTheme = TextTheme(
    headline: _darkScreenHeadingTextStyle,
    body1: _darkScreenTaskNameTextStyle,
    body2: _darkScreenTaskDurationTextStyle,
  );

  static final TextStyle _lightScreenHeadingTextStyle = TextStyle(fontSize: 48.0, color: _lightOnPrimaryColor);
  static final TextStyle _lightScreenTaskNameTextStyle = TextStyle(fontSize: 20.0, color: _lightOnPrimaryColor);
  static final TextStyle _lightScreenTaskDurationTextStyle = TextStyle(fontSize: 16.0, color: Colors.grey);

  static final TextStyle _darkScreenHeadingTextStyle = _lightScreenHeadingTextStyle.copyWith(color: _darkOnPrimaryColor);

  static final TextStyle _darkScreenTaskNameTextStyle = _lightScreenTaskNameTextStyle.copyWith(color: _darkOnPrimaryColor);

  static final TextStyle _darkScreenTaskDurationTextStyle = _lightScreenTaskDurationTextStyle;
}
//////////////////////////home.dart//////////////////////////////////////
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:hive/hive.dart';

class Home extends StatelessWidget {
  var box = Hive.box('darkModeTutorial');
  @override
  Widget build(BuildContext context) {
    var darkMode = box.get('darkMode', defaultValue: false);
    return Scaffold(
      appBar: AppBar(
        elevation: 0,
        leading: Padding(
          padding: const EdgeInsets.all(16),
          child: Icon(Icons.menu),
        ),
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.only(left: 16, right: 32, top: 32),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Text(
                  "Today",
                  style: Theme.of(context).textTheme.headline,
                ),
                Icon(Icons.add_circle_outline),
              ],
            ),
          ),
          Padding(
            padding: const EdgeInsets.only(top: 16),
            child: Card(
              color: Theme.of(context).colorScheme.primary,
              elevation: 4,
              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
              margin: const EdgeInsets.symmetric(horizontal: 20),
              child: ListTile(
                leading: Icon(
                  Icons.call,
                  color: Theme.of(context).iconTheme.color,
                ),
                title: Text(
                  "Conference Call",
                  style: Theme.of(context).textTheme.body1,
                ),
                subtitle: Text("30 mins", style: Theme.of(context).textTheme.body2),
                trailing: Icon(Icons.check_circle, color: Theme.of(context).colorScheme.secondary),
              ),
            ),
          ),
          Spacer(),
          Padding(
            padding: const EdgeInsets.all(16.0),
            child: Row(
              children: [
                Text('Dark Mode', style: Theme.of(context).textTheme.body2),
                Spacer(),
                Switch(
                  value: darkMode,
                  onChanged: (val) {
                    box.put('darkMode', !darkMode);
                  },
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}