import 'package:flutter/material.dart';

import 'CategoriesScreen.dart';
import 'SpaceScreen.dart';

// MAIN UI 底部导航栏
class AppScreen extends StatefulWidget {
  const AppScreen({Key? key}) : super(key: key);

  @override
  State<AppScreen> createState() => _AppScreenState();
}

class _AppScreenState extends State<AppScreen> {
  static const List<Widget> _widgetOptions = <Widget>[
    const CategoriesScreen(),
    const SpaceScreen(),
  ];
  static const _navigationItems = <BottomNavigationBarItem>[
    const BottomNavigationBarItem(
      icon: Icon(Icons.public),
      label: '浏览',
    ),
    const BottomNavigationBarItem(
      icon: Icon(Icons.face),
      label: '我的',
    ),
  ];

  late int _selectedIndex = 0;

  void _onItemTapped(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: IndexedStack(
        index: _selectedIndex,
        children: _widgetOptions,
      ),
      bottomNavigationBar: BottomNavigationBar(
        items: _navigationItems,
        currentIndex: _selectedIndex,
        iconSize: 20,
        selectedFontSize: 12,
        unselectedFontSize: 12,
        onTap: _onItemTapped,
      ),
    );
  }
}