import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show SynchronousFuture;
import 'package:flutter_localizations/flutter_localizations.dart';

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

class ZDLocalizations {
  ZDLocalizations(this.locale);

  final Locale locale;

  static ZDLocalizations of(BuildContext context) {
    return Localizations.of<ZDLocalizations>(context, ZDLocalizations);
  }

  static Map<String, Map<String, String>> _localizedValues = {
    'en': {
      'title': 'List View',
    },
    'zh': {
      'title': '列表视图',
    },
  };

  String get title {
    return _localizedValues[locale.languageCode]['title'];
  }
}

class DemoLocalizationsDelegate extends LocalizationsDelegate<ZDLocalizations> {
  const DemoLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) => ['en', 'zh'].contains(locale.languageCode);

  @override
  Future<ZDLocalizations> load(Locale locale) {
    // Returning a SynchronousFuture here because an async "load" operation
    // isn't needed to produce an instance of DemoLocalizations.
    return SynchronousFuture<ZDLocalizations>(ZDLocalizations(locale));
  }

  @override
  bool shouldReload(DemoLocalizationsDelegate old) => false;
}

// 静态类
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // final wordPair = new WordPair.random();
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      home: new CreateHome(),
      theme: new ThemeData(
        primaryColor: Colors.orange,
      ),
      // 国际化
      localizationsDelegates: [
        const DemoLocalizationsDelegate(),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [const Locale('en', ''), const Locale('zh', '')],
    );
  }
}

// 动态类
class CreateHome extends StatefulWidget {
  @override
  CreateHomeState createState() => CreateHomeState();
}

class CreateHomeState extends State<CreateHome> {
  int _currentIndex = 0;
  final _bodyOptions = [
    Text('主页'),
    Text('商城'),
    Text('消息'),
  ];

  // IBAction
  void backOnPressed() {}

  void menuOnPressed() {}

  void onTabBarItemTapped(int idx) {
    setState(() {
      _currentIndex = idx;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: _createAppBar(),
      body: Center(child: _bodyOptions.elementAt(_currentIndex)),
      bottomNavigationBar: _createTabBar(),
    );
  }

  Widget _createAppBar() {
    return new AppBar(
      brightness: Brightness.dark,
      elevation: 0.5,
      iconTheme: IconThemeData(color: Colors.white),
      title: Text(
        ZDLocalizations.of(context).title,
        style: TextStyle(color: Colors.white),
      ),
      actions: [
        IconButton(
          icon: Icon(Icons.menu),
          onPressed: menuOnPressed,
        ),
      ],
      leading: IconButton(
        icon: Icon(
          Icons.arrow_back_ios,
        ),
        onPressed: backOnPressed,
      ),
    );
  }

  Widget _createTabBar() {
    return new BottomNavigationBar(
      fixedColor: Colors.blue,
      backgroundColor: Colors.orange,
      currentIndex: _currentIndex,
      onTap: onTabBarItemTapped,
      items: [
        BottomNavigationBarItem(icon: Icon(Icons.home), label: '主页'),
        BottomNavigationBarItem(icon: Icon(Icons.shop), label: '商城'),
        BottomNavigationBarItem(icon: Icon(Icons.message), label: '消息')
      ],
    );
  }
}