参数类型 'StateProvider<MainPageDataController?>' 不能分配给参数类型"ProviderBase<Object？、MainPageData

Question

我试图从API获取电影细节的数据。

我在第31行和第32行得到两个错误。

第31行-

The argument type 'StateProvider<MainPageDataController?>' can't be assigned to the parameter type 'ProviderBase<Object?, MainPageDataController?>'   

这是在第32行，在"词——

The getter 'state' isn't defined for the type 'StateProvider<MainPageDataController?>'.
Try importing the library that defines 'state', correcting the name to the name of an existing getter, or defining a getter or field named 'state'

下面是代码-

import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:movie_app/controllers/main_page_data_controller.dart';
import 'package:movie_app/model/main_page_data.dart';
import 'package:movie_app/model/movie.dart';
import 'package:movie_app/model/search_category.dart';
import 'package:movie_app/widgets/movie_tile.dart';
final mainPageDataControllerProvider =
StateProvider<MainPageDataController?>((ref) {
return MainPageDataController();
});
class MainPage extends ConsumerWidget {
double? _deviceHeight;
double? _deviceWidth;
MainPageDataController? _mainPageDataController;
MainPageData? _mainPageData;
TextEditingController? _searchTextFieldController;
@override
Widget build(BuildContext context, ScopedReader watch) {
_deviceHeight = MediaQuery.of(context).size.height;
_deviceWidth = MediaQuery.of(context).size.width;
_searchTextFieldController = TextEditingController();
_mainPageDataController = watch(mainPageDataControllerProvider);
_mainPageData = watch(mainPageDataControllerProvider.state);
return _buildUI();
}
Widget _buildUI() {
return Scaffold(
resizeToAvoidBottomInset: false,
backgroundColor: Colors.black,
body: Container(
height: _deviceHeight,
width: _deviceWidth,
child: Stack(
alignment: Alignment.center,
children: [
_backgroundWidget() ?? const Text('No image to load'),
_foregroundWidget() ?? const Text('No Foreground to load'),
],
),
),
);
}
Widget? _backgroundWidget() {
return Container(
height: _deviceHeight,
width: _deviceWidth,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(10.0),
image: const DecorationImage(
image: NetworkImage(
'https://c4.wallpaperflare.com/wallpaper/474/998/395/cillian-murphy-tom-hardy-dunkirk-best-movies-wallpaper-preview.jpg',
),
fit: BoxFit.cover,
//image: AssetImage('assets/images/logo.png'),
),
),
child: BackdropFilter(
filter: ImageFilter.blur(sigmaX: 40.0, sigmaY: 40.0),
child: Container(
decoration: BoxDecoration(
color: Colors.black.withOpacity(0.2),
),
),
),
);
}
Widget? _foregroundWidget() {
return Container(
padding: EdgeInsets.only(top: _deviceHeight! * 0.02),
width: _deviceWidth! * 0.88,
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
_topBarWidget() ??
const SizedBox(
child: Text(
"Can't load Bar",
style: TextStyle(color: Colors.white),
),
),
Container(
height: _deviceHeight! * 0.83,
padding: EdgeInsets.symmetric(vertical: _deviceHeight! * 0.01),
child: _moviesListViewWidget(),
),
],
),
);
}
Widget? _topBarWidget() {
return Container(
height: _deviceHeight! * 0.08,
decoration: BoxDecoration(
color: Colors.black54,
borderRadius: BorderRadius.circular(20.0),
),
child: Row(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
searchFieldWidget(),
_categorySelectionWidget(),
],
),
);
}
Widget searchFieldWidget() {
final _border = InputBorder.none;
return Container(
width: _deviceWidth! * 0.5,
height: _deviceHeight! * 0.05,
child: TextField(
controller: _searchTextFieldController,
onSubmitted: (_input) {},
style: const TextStyle(
color: Colors.white,
),
decoration: InputDecoration(
focusedBorder: _border,
border: _border,
prefixIcon: const Icon(
Icons.search,
color: Colors.white24,
),
hintText: "Search....",
hintStyle: const TextStyle(
color: Colors.white54,
),
),
),
);
}
Widget _categorySelectionWidget() {
return DropdownButton<String>(
dropdownColor: Colors.black38,
value: SearchCategory.popular,
icon: const Icon(
Icons.menu,
color: Colors.white24,
),
items: [
DropdownMenuItem(
child: Text(
SearchCategory.popular,
style: const TextStyle(
color: Colors.white,
),
),
value: SearchCategory.popular,
),
DropdownMenuItem(
child: Text(
SearchCategory.upcoming,
style: const TextStyle(
color: Colors.white,
),
),
value: SearchCategory.upcoming,
),
DropdownMenuItem(
child: Text(
SearchCategory.none,
style: const TextStyle(
color: Colors.white,
),
),
value: SearchCategory.none,
),
],
underline: Container(
height: 1,
color: Colors.white24,
),
onChanged: (_value) {},
);
}
Widget? _moviesListViewWidget() {
final List<Movie> _movies = [];
for (var i = 0; i < 10; i++) {
_movies.add(
Movie(
name: "Movie 1",
language: "EN",
isAdult: false,
description: "Nothing for now",
rating: 8.0,
releaseDate: "2021-10-20",
posterPath: "/xGUOF1T3WmPSACQEQJfnG7Ud9f8.jpg",
backdropPath: "/9yBVqNruk6Ykrwc32qrk2TIE5xw.jpg",
),
);
}
if (_movies.isNotEmpty) {
return ListView.builder(
itemCount: _movies.length,
itemBuilder: (BuildContext _context, int _index) {
return Padding(
padding: EdgeInsets.symmetric(
vertical: _deviceHeight! * 0.01, horizontal: 0),
child: GestureDetector(
onTap: () {},
child: MovieTile(
movie: _movies[_index],
height: _deviceHeight! * 0.2,
width: _deviceWidth! * 0.85,
),
),
);
},
);
} else {
return const Center(
child: CircularProgressIndicator(
backgroundColor: Colors.white,
),
);
}
}
}

这是mainpagedatcontroller类，我声明状态参数为可选的，我在getMovies函数中获取电影-

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:get_it/get_it.dart';
import 'package:movie_app/model/main_page_data.dart';
import 'package:movie_app/model/movie.dart';
import 'package:movie_app/services/movie_service.dart';
import 'package:riverpod/riverpod.dart';
class MainPageDataController extends StateNotifier<MainPageData> {
MainPageDataController([MainPageData? state])
: super(state ?? MainPageData.initial()) {
getMovies();
}
final MovieService _movieService = GetIt.instance.get<MovieService>();
Future<void> getMovies() async {
try {
List<Movie> _movies = [];
_movies = await _movieService.getPopularMovies(page: state.page);
} catch (e) {}
}
}

Answer 1

用StateNotifierProvider代替StateProvider

final mainPageDataControllerProvider =
StateNotifierProvider<MainPageDataController?, MainPageData?>((ref) {
return MainPageDataController();
});