导航栏从'package:flutter/src/material/navigation_bar.dart'和'package:flutter_onboarding_slider/navigat

Question

**我在运行时遇到了错误，这是因为包或其他东西，我删除了所有旧代码并添加了新的，仍然面临以下错误。

错误:'NavigationBar'是从两个'package:flutter/src/material/navigation_bar. '导入的。Dart '和'package:flutter_onboarding_slider/navigation_bar.dart'。appBar: NavigationBar (^^^^^^^^^^^^^警告:空感知操作'?的操作数。'的类型'GoogleMapController'不包括null。lib/…/地图/map.dart: 62

• 'GoogleMapController'来自'package:google_maps_flutter/google_maps_flutter. '飞镖' ('/D:/颤振/.pub-cache/托管/pub.dartlang.org/google_maps_flutter-2.1.7/lib/google_maps_flutter.dart’)。包:google_maps_flutter/google_maps_flutter.dart: 1_controller ? .animateCamera (CameraUpdate.newCameraPosition (CameraPosition (^

  进口"包:颤振/cupertino.dart";导入的包:颤振/material.dart ';导入的包:flutter_onboarding_slider/flutter_onboarding_slider.dart ';导入的包:fyppedometer/mainScreens/导航/navigationBar.dart";导入的包:fyppedometer/widget/constants.dart";导入的包:fyppedometer/widget/text.dart的;

  类MyHome扩展StatefulWidget {const MyHome({钥匙吗?Key}): super(Key: Key);

  @override
  State<MyHome> createState() => _MyHomeState();
  

  }

  类_myhomeestate扩展状态{final Color kDarkBlueColor = Colors.cyan;

  // ignore: non_constant_identifier_names
  List<String> numbers_Height = [
  for (var i = 1.1; i <= 10.0; i = i + 0.1) i.toString()
  ];
  // ignore: non_constant_identifier_names
  List<String> numbers_Weight = [for (var i = 1; i <= 1000; i++) i.toString()];
  int _groupValue = -1;
  String _selectedGender = 'male';
  @override
  Widget build(BuildContext context) {
  Size size = MediaQuery.of(context).size;
  return Container(
  // color: Colors.amber,
  child: OnBoardingSlider(
  buttonText: 'Start',
  onFinish: () {
  Navigator.push(
  context,
  CupertinoPageRoute(
  builder: (context) => Navbar(),
  ),
  );
  },
  buttonTextColor: Colors.cyan,
  // skipTextButton: Text(
  //   'Skip',
  //   style: TextStyle(
  //     fontSize: 16,
  //     color: kDarkBlueColor,
  //     fontWeight: FontWeight.w600,
  //   ),
  // ),
  // trailing: Text(
  //   'Login',
  //   style: TextStyle(
  //     fontSize: 16,
  //     color: kDarkBlueColor,
  //     fontWeight: FontWeight.w600,
  //   ),
  // ),
  // trailingFunction: () {
  //   // Navigator.push(
  //   //   context,
  //   //   CupertinoPageRoute(
  //   //     builder: (context) => LoginPage(),
  //   //   ),
  //   // );
  // },
  controllerColor: kDarkBlueColor,
  totalPage: 3,
  headerBackgroundColor: liteblue,
  pageBackgroundColor: liteblue,
  background: [
  Padding(
  padding: const EdgeInsets.only(top: 210, left: 80),
  child: Image.asset(
  'assets/gender.png',
  height: MediaQuery.of(context).size.height * 0.6,
  width: MediaQuery.of(context).size.width * 0.6,
  ),
  ),
  Padding(
  padding: const EdgeInsets.only(top: 160, left: 60),
  child: Image.asset(
  'assets/walking.png',
  height: MediaQuery.of(context).size.height * 0.7,
  width: MediaQuery.of(context).size.width * 0.7,
  ),
  ),
  Padding(
  padding: const EdgeInsets.only(top: 200, left: 60),
  child: Image.asset(
  'assets/human.png',
  height: MediaQuery.of(context).size.height * 0.6,
  width: MediaQuery.of(context).size.width * 0.6,
  ),
  ),
  ],
  speed: 1.8,
  pageBodies: [
  Container(
  // padding: EdgeInsets.symmetric(horizontal: 40),
  child: Column(
  mainAxisAlignment: MainAxisAlignment.start,
  crossAxisAlignment: CrossAxisAlignment.center,
  children: <Widget>[
  const Text(
  'What’s Your Gender',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white,
  fontSize: 24.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 10,
  ),
  const Text(
  'Calories & Stride length calculation need it ',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white60,
  fontSize: 21.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 20,
  ),
  Column(
  crossAxisAlignment: CrossAxisAlignment.start,
  children: [
  Container(
  height: size.height * 0.1,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius:
  BorderRadius.circular(25), // radius of 10
  color: Color.fromARGB(255, 19, 65, 103),
  ),
  child: Center(
  child: ListTile(
  leading: Radio<String>(
  activeColor: Colors.white,
  value: 'male',
  groupValue: _selectedGender,
  onChanged: (value) {
  setState(() {
  _selectedGender = value!;
  });
  },
  ),
  title: text(
  textData: "Male",
  color: Colors.white,
  fontsize: 20.0,
  fontweight: FontWeight.bold),
  //  Text(_selectedGender == 'male' ? 'Hello gentlement!' : 'Hi lady!')
  ),
  ),
  ),
  SizedBox(height: 20),
  Container(
  height: size.height * 0.1,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius:
  BorderRadius.circular(25), // radius of 10
  color: Color.fromARGB(255, 19, 65, 103),
  ),
  child: Center(
  child: ListTile(
  leading: Radio<String>(
  activeColor: Colors.white,
  value: 'female',
  groupValue: _selectedGender,
  onChanged: (value) {
  setState(() {
  _selectedGender = value!;
  });
  },
  ),
  title: text(
  textData: "Female",
  color: Colors.white,
  fontsize: 20.0,
  fontweight: FontWeight.bold),
  //  Text(_selectedGender == 'male' ? 'Hello gentlement!' : 'Hi lady!')
  ),
  ),
  ),
  ],
  )
  ]),
  ),
  Container(
  // padding: EdgeInsets.symmetric(horizontal: 40),
  child: Column(
  mainAxisAlignment: MainAxisAlignment.start,
  crossAxisAlignment: CrossAxisAlignment.center,
  children: <Widget>[
  const Text(
  'How Tall are you?',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white,
  fontSize: 28.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 10,
  ),
  const Text(
  'To Personalize Your Fitness Goal ',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white60,
  fontSize: 20.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 20,
  ),
  Column(
  crossAxisAlignment: CrossAxisAlignment.start,
  children: [
  Center(
  child: Container(
  height: size.height * 0.10,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius: BorderRadius.circular(15),
  border: Border.all(
  color: Color.fromARGB(255, 145, 174, 225))),
  child: Center(
  child: text(
  textData: "Height",
  fontsize: 30.0,
  fontweight: FontWeight.bold,
  color: Color.fromARGB(255, 147, 148, 152)),
  ),
  ),
  ),
  SizedBox(
  height: 30,
  ),
  Center(
  child: Container(
  height: size.height * 0.13,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius: BorderRadius.circular(20),
  border: Border.all(
  color: Color.fromARGB(255, 92, 89, 89)),
  // color: Colors.white,
  ),
  child: ListWheelScrollView.useDelegate(
  itemExtent: 100,
  // controller: fixedExtentScrollController,
  physics: FixedExtentScrollPhysics(),
  onSelectedItemChanged: (i) {
  print(numbers_Height[i]);
  },
  childDelegate: ListWheelChildLoopingListDelegate(
  children: <Widget>[
  ...numbers_Height.map((String number) {
  
  return Center(
  child: Text(
  number,
  style: const TextStyle(
  fontSize: 28.0,
  color: Colors.white,
  fontWeight: FontWeight.bold,
  fontStyle: FontStyle.normal,
  decoration: TextDecoration.none),
  ),
  );
  })
  ],
  ),
  ),
  ),
  )
  ],
  )
  ]),
  ),
  Container(
  // padding: EdgeInsets.symmetric(horizontal: 40),
  child: Column(
  mainAxisAlignment: MainAxisAlignment.start,
  crossAxisAlignment: CrossAxisAlignment.center,
  children: <Widget>[
  const Text(
  'How much do you Weight?',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white,
  fontSize: 28.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 10,
  ),
  const Text(
  'To Personalize Your Fitness Goal ',
  textAlign: TextAlign.center,
  style: TextStyle(
  color: Colors.white60,
  fontSize: 20.0,
  fontWeight: FontWeight.w600,
  ),
  ),
  const SizedBox(
  height: 20,
  ),
  Column(
  crossAxisAlignment: CrossAxisAlignment.start,
  children: [
  Center(
  child: Container(
  height: size.height * 0.10,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius: BorderRadius.circular(15),
  border: Border.all(
  color: Color.fromARGB(255, 145, 174, 225))),
  child: Center(
  child: text(
  textData: "Weight",
  fontsize: 30.0,
  fontweight: FontWeight.bold,
  color: Color.fromARGB(255, 147, 148, 152)),
  ),
  ),
  ),
  SizedBox(
  height: 30,
  ),
  Center(
  child: Container(
  height: size.height * 0.13,
  width: size.width * 0.5,
  decoration: BoxDecoration(
  borderRadius: BorderRadius.circular(20),
  border: Border.all(
  color: Color.fromARGB(255, 92, 89, 89)),
  ),
  child: ListWheelScrollView.useDelegate(
  itemExtent: 100,
  physics: FixedExtentScrollPhysics(),
  onSelectedItemChanged: (i) {
  print(numbers_Weight[i]);
  },
  childDelegate: ListWheelChildLoopingListDelegate(
  children: <Widget>[
  ...numbers_Weight.map((String number) {
  return Center(
  child: Text(
  number, //Here is the child value I would like to get
  style: const TextStyle(
  fontSize: 28.0,
  color: Colors.white,
  fontWeight: FontWeight.bold,
  fontStyle: FontStyle.normal,
  decoration: TextDecoration.none),
  ),
  );
  })
  ],
  ),
  ),
  ),
  )
  ],
  )
  ]),
  ),
  ],
  ),
  );
  }
  

  }

Answer 1

使用show和hide导入部分库

// Import only foo.
import 'package:lib1/lib1.dart' show foo;
// Import all names EXCEPT foo.
import 'package:lib2/lib2.dart' hide foo;

详情请参见使用库。

Answer 2

要解决这个问题，首先导入带有变量的包: -

import 'package:QualityCheckApp/upgrade/screens/home/navigation_drawer.dart' as nav;

然后使用类/部件

drawer: nav.NavigationDrawer(),