下面是工作代码。尝试在https://dartpad.dev/中运行它

import 'package:flutter/material.dart';

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

  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        title: 'Flutter Demo',
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
          useMaterial3: true,
        ),
        home: Nav(),
      );
    }
  }

  class Nav extends StatefulWidget {
    @override
    State<Nav> createState() {
      return _NavState();
    }
  }

  class _NavState extends State<Nav> { 
    int myCurrentIndex = 0;
    // List Pages = const[
    //   MachineStatus(),
    //   WaterGenerate(),
    //   // DewPoint(),
    //   // MachineInfo(),
    // ];
    List pages = const [
      MachineStatusPage(),
      MachineStatusPage(),
      MachineStatusPage(),
      MachineStatusPage(),
      // MachinePage(),
      // WaterPage(),
      // DewPoint(),
      // MachineInfo(),
    ];
    // void onClicked(int index) {
    //   setState(() {
    //     myCurrentIndex = index;
    //   });
    // }

    @override
    Widget build(BuildContext context) {
      // Widget activePage = const MachineStatusPage();
      // if (_selectedPageIndex == 1){
      //   activePage = WaterGenaratePage();
      // }
      return Scaffold(
        bottomNavigationBar:
        Container(
          margin: EdgeInsets.symmetric(horizontal: 20, vertical: 40,),
          decoration: BoxDecoration(
            boxShadow: [
              BoxShadow(
                color: Colors.black,
                blurRadius: 25,
              ),
            ]
          ),
          child: BottomNavigationBar(
            backgroundColor: Colors.white,
            selectedItemColor: Colors.amber,
            unselectedItemColor: Colors.black,
            currentIndex: myCurrentIndex,
            onTap: (index) {
              setState(() {
                myCurrentIndex = index;
              });
            },
            items: const <BottomNavigationBarItem> [
            BottomNavigationBarItem(
              icon: Icon(Icons.power),
              label: 'Status',
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.water),
              label: 'Water',
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.dew_point),
              label: 'Dew Point',
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.info),
              label: 'Chassis Info',
            ),
          ],),
        ),
        body: pages[myCurrentIndex],
        // activePage,
      );
    }
  }

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

    // This widget is the root of your application.
    @override
    Widget build(BuildContext context) {
      return MachinePage(machine: 0011, nickname: "Home");
    }
  }
  class MachinePage extends StatefulWidget {
    // const MachinePage({super.key});
    var machine;
    var nickname;
    MachinePage({Key? mykey, this.machine, this.nickname}) : super(key: mykey);
    @override
    State<MachinePage> createState() {
      return _MachinePageState();
    }

  }
  class _MachinePageState extends State<MachinePage> {

    var Version;
    var Comp;
    var Comp_Status;
    var arh;
    var adp;
    var temp;
    var status;

    var machine_id;
    bool loading = false;
     @override
    Widget build(BuildContext context) {
      return Scaffold(
        backgroundColor: Color.fromARGB(220, 50, 99, 125),
        appBar: AppBar(
            backgroundColor: Theme.of(context).colorScheme.inversePrimary,
            title: Text('Machine Status'),
            actions: <Widget>[
              IconButton(
                icon: Icon(
                  Icons.logout,
                  color: Colors.white,
                ),
                onPressed: () {
  //                 Navigator.pushReplacement(
  //                     context,
  //                     MaterialPageRoute(
  //                         builder: (context) => MyHomePage(title: 'Flutter Demo Home Page',))
  //                 );
                },
              )
            ]
        ),
        // bottomNavigationBar: Nav(),
        body: Column(
          children: [
            Container(
                child: Center(
                  child: Column(
                    children: [
                      SizedBox(height: 40,),
                      Text("Machine Id :  ${widget.machine}", style: TextStyle(fontSize: 20, fontWeight: FontWeight.w700,color: Colors.white, )),
                      SizedBox(height: 10,),
                      Text("Nick Name : ${widget.nickname}", style: TextStyle(fontSize: 20, fontWeight: FontWeight.w700,color: Colors.white,)),
                      // Image(image:  new AssetImage("assets/images/mstatus.png")),
                      SizedBox(height: 80,),
                      ElevatedButton(
                        onPressed: () {},
                        child: Text('ON', style: TextStyle(color: Colors.white, fontSize: 20,)),
                        style: ElevatedButton.styleFrom(
                          shape: CircleBorder(),
                          padding: EdgeInsets.all(80),
                          backgroundColor: Colors.blue, // <-- Button color
                          foregroundColor: Colors.red, // <-- Splash color
                        ),
                      ),

                    ],
                    // ),
                  ),
                ),
              ),
            // Nav(),
          ],
        ),
        // bottomNavigationBar: Nav(),
        //   ),
        // ),
      );
    }
  }

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image here正在工作！提供的代码成功执行。请查看您的日志。

@SalmanAhmed是对的。导航栏处于无限循环中。
您正在从MachineStatusPage调用Nav，而Nav正在再次调用MachineStatusPage，此循环将继续。
我想你可能想使用MachinePage而不是MachineStatusPage。你只是把它输错了吗？
尝试从列表中删除MachineStatusPage或将其重命名为MachinePage（）。像这样：

List pages = const [
    MachinePage(),
    waterPage(),
    DewPoint(),
    MachineInfo(),
    // MachinePage(),
    // WaterPage(),
    // Dew Point(),
    // MachineInfo(),
  ];

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而不是：

List pages = const [
    MachineStatusPage(),
    waterPage(),
    DewPoint(),
    MachineInfo(),
    // MachinePage(),
    // WaterPage(),
    // DewPoint(),
    // MachineInfo(),
  ];

型