在我的flutter应用程序中，selectedItemcolor没有改变

Question

在我的 flutter 应用程序中，当我尝试使用 Navigator.push( 导航到另一个屏幕时， selectedItemcolor 不会改变 语境， MaterialPageRoute(构建器：(上下文) => _pages.elementAt(index)), );

这是完整代码

import 'package:flutter/material.dart';

class BottomBar extends StatefulWidget {
  const BottomBar({Key? key}) : super(key: key);

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

class _BottomBarState extends State<BottomBar> {
  int _SelectedIndex = 0;

  final List<Widget> _pages = <Widget>[
    Home(),
    Order(),
    Profile(),
  ];

  void onTabTapped(int index) {
    setState(() {
      _SelectedIndex = index;
    });
    Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => _pages.elementAt(index)),
    );
  }

  @override
  Widget build(BuildContext context) {
    return BottomNavigationBar(
      items: <BottomNavigationBarItem>[
        BottomNavigationBarItem(
          icon: Icon(Icons.home),
          label: "Home",
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.card_travel),
          label: "Orders",
        ),
        BottomNavigationBarItem(icon: Icon(Icons.person), label: "Profile"),
      ],
      currentIndex: _SelectedIndex,
      onTap: onTabTapped,
    );
  }
}

Answer 1

您不应使用导航器更改活动页面。

BottomNavigationBar

负责导航。请检查以下示例：

import 'package:flutter/material.dart';

void main() => runApp(const BottomNavigationBarExampleApp());

class BottomNavigationBarExampleApp extends StatelessWidget {
  const BottomNavigationBarExampleApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: BottomNavigationBarExample(),
    );
  }
}

class BottomNavigationBarExample extends StatefulWidget {
  const BottomNavigationBarExample({super.key});

  @override
  State<BottomNavigationBarExample> createState() =>
      _BottomNavigationBarExampleState();
}

class _BottomNavigationBarExampleState
    extends State<BottomNavigationBarExample> {
  int _selectedIndex = 0;
  static const List<Widget> _widgetOptions = <Widget>[
    Text('Index 0: Home'),
    Text('Index 1: Orders'),
    Text('Index 2: Profile'),
  ];

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('BottomNavigationBar Sample'),
      ),
      body: Center(
        child: _widgetOptions.elementAt(_selectedIndex),
      ),
      bottomNavigationBar: BottomNavigationBar(
        items: const <BottomNavigationBarItem>[
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: 'Home',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.business),
            label: 'Orders',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.school),
            label: 'Profile',
          ),
        ],
        currentIndex: _selectedIndex,
        selectedItemColor: Colors.amber[800],
        onTap: _onItemTapped,
      ),
    );
  }
}