In below code I facing problem when I access the map in body argument it will show error object? type can't be assign to widget? type so I use as Widget after running the I get the error which I asking here, so how to access the widget(constructor here) without getting these error.

import 'package:flutter/material.dart';

import '../screens/categories_screen.dart';
import '../screens/favorites_screen.dart';

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

  @override
  State<TabsScreenBottom> createState() => _TabsScreenBottomState();
}

class _TabsScreenBottomState extends State<TabsScreenBottom> {
  final List<Map<String, Object>> _pages = const [
    {
      'page': CategoriesScreen(),
      'title': 'Categories',
    },
    {
      'page': FavoritesScreen(),
      'title': 'My Favorites',
    },
  ];

  int _selectedPageIndex = 0;

  void _selectPage(int index) {
    setState(() {
      _selectedPageIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Meal'),
      ),
      body: _pages[_selectedPageIndex]['page'] as Widget,
      bottomNavigationBar: BottomNavigationBar(
        backgroundColor: Theme.of(context).colorScheme.primary,
        selectedItemColor: Theme.of(context).colorScheme.secondary,
        unselectedItemColor: Colors.white,
        currentIndex: _selectedPageIndex,
        // type: BottomNavigationBarType.shifting,
        // giving animation when tab is changed
        onTap: _selectPage,
        items: [
          BottomNavigationBarItem(
            backgroundColor: Theme.of(context).colorScheme.primary,
            icon: const Icon(
              Icons.category,
            ),
            label: 'Categorey',
          ),
          BottomNavigationBarItem(
            // if your use type shifting
            backgroundColor: Theme.of(context).colorScheme.primary,
            icon: const Icon(
              Icons.star,
            ),
            label: 'Favorites',
          ),
        ],
      ),
    );
  }
}

CodePudding user response：

Once change your List<Map<String, Object>> to List<Map<String, dynamic>>

I hope this things are solve your issue.

CodePudding user response：

try to change List<Map<String, Object>> to List<Map<String, dynamic>> and it should work.

Coming to your question:

Why it does't work with Object type ?

Lets look at the list item you have

{
 'page': CategoriesScreen(),
 'title': 'Categories',
},

Here on the left end side you have String field and hence the same we've used in the Map

Now if you will notice right end data type there are 2 type of values

1. CategoriesScreen() this is a type of Widget
2. 'Categories' this is type of String

Hence because we have multiple type of values, we need a certain type that can adapt both that's why we've used dynamic