提供程序在屏幕上调用小部件时出错

Question

为了简单起见，我正在创建一个仪表板，其中我在屏幕左侧有一个Drawer ，另一个小部件会根据用户从抽屉中选择的内容而改变。 无论如何，在为菜单项添加onPressed之后，当我按下以重新调用抽屉旁边的新小部件时，出现此错误：

Could not find the correct provider<MenuController$> above MainScreen Widget.

所以首先这是我的main.dart ：

    import 'package:admin/constants.dart';
import 'package:admin/controllers/MenuController.dart';
import 'package:admin/screens/dashboard/dashboard_screen.dart';
import 'package:admin/screens/main/main_screen.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:provider/provider.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Admin Panel',
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: bgColor,
        textTheme: GoogleFonts.poppinsTextTheme(Theme.of(context).textTheme)
            .apply(bodyColor: Colors.white),
        canvasColor: secondaryColor,
      ),
      home: MultiProvider(
        providers: [
          ChangeNotifierProvider(
            create: (context) => MenuController(),
          ),
        ],
        child: MainScreen(DashboardScreen()),,
      ),
    );
  }
}

这是我的MenuController ：

    import 'package:flutter/material.dart';

class MenuController extends ChangeNotifier {
  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

  GlobalKey<ScaffoldState> get scaffoldKey => _scaffoldKey;

  void controlMenu() {
    if (!_scaffoldKey.currentState.isDrawerOpen) {
      _scaffoldKey.currentState.openDrawer();
    }
  }
}

这是我的main_screen ：

    import 'package:admin/controllers/MenuController.dart';
import 'package:admin/responsive.dart';
import 'package:admin/screens/dashboard/dashboard_screen.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import 'components/side_menu.dart';

class MainScreen extends StatefulWidget {
  Widget newWidget;
  MainScreen(this.newWidget);
  @override
  State<MainScreen> createState() => _MainScreenState();
}

class _MainScreenState extends State<MainScreen> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      key: context.read<MenuController>().scaffoldKey,
      drawer: SideMenu(),
      body: SafeArea(
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // We want this side menu only for large screen
            if (Responsive.isDesktop(context))
              Expanded(
                // default flex = 1
                // and it takes 1/6 part of the screen
                child: SideMenu(),
              ),
            Expanded(
              // It takes 5/6 part of the screen
              flex: 5,
              child: DashboardScreen(),
            ),
          ],
        ),
      ),
    );
  }
}

最后这是我的side_menu ：

DrawerListTile(
          title: "Fournisseurs",
          svgSrc: "assets/icons/menu_tran.svg",
          subTitle1: 'Ajouter Un Fournisseur',
          subTitle2: 'Liste Des Fournisseurs',
          subTitle3: '---------',
          press1: () {
            Navigator.push(
              context,
              MaterialPageRoute(
                  builder: (context) => MainScreen(Text('Hello'))),
            );
          },

在我的Drawer中单击此按钮后，出现上面列出的错误。

Answer 1

正如错误所述，在 MainScreen Widget 上方找不到正确的提供程序。

看看它是否有助于像这样构建您的 main.dart：

import 'package:admin/constants.dart';
import 'package:admin/controllers/MenuController.dart';
import 'package:admin/screens/dashboard/dashboard_screen.dart';
import 'package:admin/screens/main/main_screen.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:provider/provider.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider(
          create: (context) => MenuController(),
        ),
      ],
      child: MaterialApp(
        debugShowCheckedModeBanner: false,
        title: 'Flutter Admin Panel',
        theme: ThemeData.dark().copyWith(
          scaffoldBackgroundColor: bgColor,
          textTheme: GoogleFonts.poppinsTextTheme(Theme.of(context).textTheme)
              .apply(bodyColor: Colors.white),
          canvasColor: secondaryColor,
        ),
        home: MainScreen(DashboardScreen()),
      ),
    );
  }
}