移动到其他页面时无法保持底部导航栏颤动

如何解决移动到其他页面时无法保持底部导航栏颤动

我是初学者，我试过这个教程 https://youtu.be/1ToqYMSnNhA 但是当我按下其他按钮并导航到另一个屏幕时..底部栏正在消失。如何让它粘住？ 我得到“底部充满无限像素”代替底部导航栏。

#main.dart
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,home: Splashscreen(),routes: <String,WidgetBuilder>{
        "/login": (BuildContext context) => LoginSignupScreen(),"/profile": (BuildContext context) => Profile(),"/home": (BuildContext context) => Home(),"/splashscreen": (BuildContext context) => Splashscreen(),"/department": (BuildContext context) => Department(),},);
  }
}


#navbar.dart
import 'package:Flutter/material.dart';
import 'package:mini_project/main.dart';

class Navbar extends StatefulWidget {
  @override
  _NavbarState createState() => _NavbarState();
}

class _NavbarState extends State<Navbar> {
  int currentIndex = 0;

  setBottomBarIndex(index) {
    setState(() {
      currentIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    final Size size = MediaQuery.of(context).size;
    return Scaffold(
      backgroundColor: Colors.white.withAlpha(55),body: Stack(
        children: [
          Positioned(
            bottom: 0,left: 0,child: Container(
              width: size.width,height: 80,child: Stack(
                //overflow: Overflow.visible,children: [
                  CustomPaint(
                    size: Size(size.width,80),painter: BCustomPainter(),),Center(
                    heightFactor: 0.6,child: FloatingActionButton(
                        backgroundColor: Colors.blueAccent[100],child: Icon(Icons.home),elevation: 0.1,onpressed: () {}),Container(
                    width: size.width,child: Row(
                      mainAxisAlignment:
                          MainAxisAlignment.spaceEvenly,//to align evenly
                      children: [
                        IconButton(
                          icon: Icon(
                            Icons.account_circle,size: 30.0,color: currentIndex == 0
                                ? Colors.blueAccent[100]
                                : Colors.grey.shade400,onpressed: () {
                            setBottomBarIndex(0);
                            Navigator.pushReplacementNamed(context,"/profile");
                          },splashColor: Colors.white,IconButton(
                            icon: Icon(
                              Icons.dynamic_Feed,color: currentIndex == 1
                                  ? Colors.blueAccent[100]
                                  : Colors.grey.shade400,onpressed: () {
                              setBottomBarIndex(1);
                            }),Container(
                          width: size.width * 0.20,IconButton(
                            icon: Icon(
                              Icons.workspaces_filled,color: currentIndex == 2
                                  ? Colors.blueAccent[100]
                                  : Colors.grey.shade400,onpressed: () {
                              setBottomBarIndex(2);
                              Navigator.pushReplacementNamed(
                                  context,"/department");
                            }),IconButton(
                            icon: Icon(
                              Icons.notifications,color: currentIndex == 3
                                  ? Colors.blueAccent[100]
                                  : Colors.grey.shade400,onpressed: () {
                              setBottomBarIndex(3);
                            }),],)
                ],)
        ],);
  }
}

//for the shape of the nav bar
class BCustomPainter extends CustomPainter {
  @override
  void paint(Canvas canvas,Size size) {
    Paint paint = new Paint()
      ..color = Colors.white
      ..style = PaintingStyle.fill;
//quadratic BezierTo curve
    Path path = Path();
    path.moveto(0,20); // Start
    path.quadraticBezierTo(size.width * 0.20,size.width * 0.35,0);
    path.quadraticBezierTo(size.width * 0.40,size.width * 0.40,20);
    path.arcToPoint(Offset(size.width * 0.60,20),radius: Radius.circular(20.0),clockwise: false);
    path.quadraticBezierTo(size.width * 0.60,size.width * 0.65,0);
    path.quadraticBezierTo(size.width * 0.80,size.width,20);
    path.lineto(size.width,size.height);
    path.lineto(0,20);
    canvas.drawShadow(path,Colors.black,5,true);
    canvas.drawPath(path,paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return false;
  }
}

我在这里附上了主文件和导航栏文件！请帮忙！

解决方法

使用此插件Presistant_bottom_nav_bar。现在您可以在每个屏幕上使用底部导航栏

初始化变量

PersistentTabController _controller =PersistentTabController(initialIndex: 0);

//Screens for each nav items.

  List<Widget> _NavScreens() {
    return [
     HomeScreen(),OfferScreen(),HelpScreen(),ProfileScreen(),CartViewScreen(),];
  }


  List<PersistentBottomNavBarItem> _navBarsItems() {
    return [
      PersistentBottomNavBarItem(
       icon: Icon(Icons.home),title: ("Home"),activeColor: CupertinoColors.activeBlue,inactiveColor: CupertinoColors.systemGrey,),PersistentBottomNavBarItem(
        icon: Icon(Icons.favorite),title: ("OFFERS"),activeColor: CupertinoColors.activeGreen,PersistentBottomNavBarItem(
        icon: Icon(Icons.person_pin),title: ("Help"),activeColor: CupertinoColors.systemRed,PersistentBottomNavBarItem(
        icon: Icon(Icons.local_activity),title: ("ProfileScreen"),activeColor: CupertinoColors.systemIndigo,PersistentBottomNavBarItem(
        icon: Icon(Icons.shop_cart),title: ("Cart"),];
  }
@override
Widget build(BuildContext context) {
    return Center(
      child: PersistentTabView(
        controller: _controller,screens: _NavScreens(),items: _navBarsItems(),confineInSafeArea: true,backgroundColor: Colors.white,handleAndroidBackButtonPress: true,resizeToAvoidBottomInset: true,hideNavigationBarWhenKeyboardShows: true,decoration: NavBarDecoration(
          borderRadius: BorderRadius.circular(10.0),popAllScreensOnTapOfSelectedTab: true,navBarStyle: NavBarStyle.style9,);
}