开源鸿蒙跨平台训练营DAY3:使用dio库实现网络请求
今天从零开始构建一个Flutter鸿蒙项目的完整过程,使用Dio库实现网络请求,调用猫咪图片API,并展示在鸿蒙和安卓双平台上,虽然是参照的网上的各种教程,但是还是感觉有些收获的。欢迎加入开源鸿蒙跨平台社区:
·
前提准备
- 因为在网上进行了一些查询,然后发现一些大佬推荐说Android Studio比较更好用,所以这一篇用的是Android Studio来做的,去网上参考了不少教程,做下来感觉也能适应。
- 关于Android Studio的相关配置,可以参考的这篇,我觉得非常详细,不容易出错Android Studio安装配置教程
1.使用Android Studio创建新项目
1.1插件准备
在进行完上面那个教程的配置过后,要下载Dart和Flutter这两个插件,在Android Studio中打开setting,点击plugins,如图(找不到可以搜索)
1.2新建项目
- 插件下载完过后会出现一个New flutter Project选项,点击这个,如图

- 会提示你选择SDK路径,将我们之前同步的flutter的路径导入就好了
- 按照项目创建项目名,选择所需要的平台(我看到的教程建议都选),然后点击create
- 然后我们需要打开终端,查看是否是正确的鸿蒙的Flutter SDK
flutter --version

- 在终端创建鸿蒙的项目,输入
flutter create --platform ohos .
1.3项目分包
- 选中lib目录选择New再选择新建文件夹,新建以下的目录,每个目录的作用如图所示(这里我参照的一位大佬的教程)

2.使用Dio实现网络请求
2.1添加dio的库
在pubspec.yaml添加dio的库,这里要和flutter对齐
- dio: ^5.5.0+1
- provider: ^6.1.2

2.2使用Dio进行网络请求并渲染UI
这里做的一个猫咪照片的
2.2.1 猫咪图片数据模型
- lib/viewmodels/cat_model.dart
- 代码如下
class CatModel {
final String id;
final String url;
final int width;
final int height;
CatModel({
required this.id,
required this.url,
required this.width,
required this.height,
});
factory CatModel.fromJson(Map<String, dynamic> json) {
return CatModel(
id: json['id'] ?? '',
url: json['url'] ?? '',
width: json['width'] ?? 0,
height: json['height'] ?? 0,
);
}
Map<String, dynamic> toJson() => {
'id': id,
'url': url,
'width': width,
'height': height,
};
}
2.2.2 猫咪API服务
- 文件路径:lib/api/cat_api.dart
- 代码如下
import 'package:app1/utils/http_util.dart';
import 'package:app1/viewmodels/cat_model.dart';
import 'package:app1/contents/api_constants.dart';
class CatApi {
static final HttpUtil _http = HttpUtil();
// 获取猫咪图片列表(基础方法)
static Future<List<CatModel>> getCatImages({
int limit = 1, // 默认只获取1张
int? page,
String? order,
bool? hasBreeds,
String? breedIds,
String? categoryIds,
int? subId,
}) async {
try {
final Map<String, dynamic> queryParams = {
'limit': limit,
};
// 添加可选参数
if (page != null) queryParams['page'] = page;
if (order != null) queryParams['order'] = order;
if (hasBreeds != null) queryParams['has_breeds'] = hasBreeds ? 1 : 0;
if (breedIds != null) queryParams['breed_ids'] = breedIds;
if (categoryIds != null) queryParams['category_ids'] = categoryIds;
if (subId != null) queryParams['sub_id'] = subId;
final data = await _http.get(
'${ApiConstants.catBaseUrl}${ApiConstants.catImagesEndpoint}',
queryParams: queryParams,
);
if (data is List) {
return data.map((json) => CatModel.fromJson(json)).toList();
} else {
throw Exception('返回数据格式错误');
}
} catch (e) {
rethrow;
}
}
// 获取单张猫咪图片(简化方法)
static Future<CatModel> getSingleCat() async {
final cats = await getCatImages(limit: 1); // ✅ 调用上面定义的方法
return cats.first;
}
// 可选:获取多张猫咪图片
static Future<List<CatModel>> getMultipleCats(int count) async {
return await getCatImages(limit: count);
}
}
2.2.3 猫咪页面调用
- 文件:lib/pages/Cats/index.dart
- 代码如下
import 'package:flutter/material.dart';
import 'package:app1/api/cat_api.dart';
import 'package:app1/viewmodels/cat_model.dart';
import 'package:app1/components/cat_card.dart';
class CatsPage extends StatefulWidget {
const CatsPage({super.key});
State<CatsPage> createState() => _CatsPageState();
}
class _CatsPageState extends State<CatsPage> {
CatModel? _cat; // ✅ 只保存一张图片
bool _isLoading = false;
String? _error;
void initState() {
super.initState();
_fetchCat(); // ✅ 只获取一张
}
Future<void> _fetchCat() async {
setState(() {
_isLoading = true;
_error = null;
});
try {
final cat = await CatApi.getSingleCat(); // ✅ 调用获取单张的方法
setState(() {
_cat = cat;
});
} catch (e) {
setState(() {
_error = e.toString();
});
} finally {
setState(() {
_isLoading = false;
});
}
}
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('随机猫咪 🐱'),
actions: [
IconButton(
icon: const Icon(Icons.refresh),
onPressed: _fetchCat, // ✅ 刷新时也只获取一张
),
],
),
body: _buildBody(),
);
}
Widget _buildBody() {
if (_isLoading) {
return const Center(child: CircularProgressIndicator());
}
if (_error != null) {
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Icon(Icons.error_outline, size: 64, color: Colors.red),
const SizedBox(height: 16),
Text('加载失败: $_error'),
const SizedBox(height: 16),
ElevatedButton(
onPressed: _fetchCat,
child: const Text('重新获取'),
),
],
),
);
}
if (_cat == null) {
return const Center(child: Text('暂无猫咪图片'));
}
// ✅ 只显示一张图片,居中显示
return SingleChildScrollView(
child: Center(
child: Padding(
padding: const EdgeInsets.all(20),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
CatCard(cat: _cat!),
const SizedBox(height: 20),
// 添加一些操作按钮
Wrap(
spacing: 12,
children: [
ElevatedButton.icon(
onPressed: _fetchCat,
icon: const Icon(Icons.refresh),
label: const Text('换一张'),
),
OutlinedButton.icon(
onPressed: () {
// 可以添加保存或分享功能
},
icon: const Icon(Icons.download),
label: const Text('保存'),
),
],
),
const SizedBox(height: 20),
// 显示详细信息
Container(
padding: const EdgeInsets.all(16),
decoration: BoxDecoration(
color: Colors.grey[50],
borderRadius: BorderRadius.circular(12),
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text(
'图片信息',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
const SizedBox(height: 8),
Text('ID: ${_cat!.id}'),
Text('宽度: ${_cat!.width} 像素'),
Text('高度: ${_cat!.height} 像素'),
Text('URL: ${_cat!.url}'),
],
),
),
],
),
),
),
);
}
}
2.2.4 猫咪卡片组件
- 文件:lib/components/cat_card.dart
- 代码如下
import 'package:flutter/material.dart';
import 'package:app1/viewmodels/cat_model.dart';
class CatCard extends StatelessWidget {
final CatModel cat;
const CatCard({
super.key,
required this.cat,
});
Widget build(BuildContext context) {
return Card(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(12),
),
elevation: 2,
child: Column(
children: [
// 猫咪图片
ClipRRect(
borderRadius: const BorderRadius.vertical(
top: Radius.circular(12),
),
child: SizedBox(
width: double.infinity,
height: 200,
child: Image.network(
cat.url,
fit: BoxFit.cover,
loadingBuilder: (context, child, loadingProgress) {
if (loadingProgress == null) return child;
return Center(
child: CircularProgressIndicator(
value: loadingProgress.expectedTotalBytes != null
? loadingProgress.cumulativeBytesLoaded /
loadingProgress.expectedTotalBytes!
: null,
),
);
},
errorBuilder: (context, error, stackTrace) {
return Container(
color: Colors.grey[100],
child: const Center(
child: Icon(
Icons.image_not_supported,
size: 50,
color: Colors.grey,
),
),
);
},
),
),
),
// 猫咪信息
Padding(
padding: const EdgeInsets.all(12),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'尺寸: ${cat.width} × ${cat.height}',
style: const TextStyle(
fontSize: 14,
fontWeight: FontWeight.w500,
),
),
const SizedBox(height: 4),
Text(
'ID: ${cat.id}', // ✅ 修复:直接显示完整ID,不截取
style: TextStyle(
fontSize: 12,
color: Colors.grey[600],
),
),
],
),
),
],
),
);
}
}
2.2.5 路由配置文件
- 文件:lib/routes/index.dart
- 代码如下
import 'package:flutter/material.dart';
import 'package:app1/pages/Login/index.dart';
import 'package:app1/pages/Main/index.dart';
import 'package:app1/pages/Cats/index.dart';
// 管理路由
import 'package:flutter/material.dart';
import 'package:app1/pages/Login/index.dart';
import 'package:app1/pages/Main/index.dart';
import 'package:app1/pages/Cats/index.dart';
// 返回App根组件
Widget getRootWidget() {
return MaterialApp(
// 命名路由
initialRoute: '/', // 默认首页
routes: getRootRoutes(),
);
}
// 返回该App的路由配置
Map<String, Widget Function(BuildContext)> getRootRoutes() {
return {
'/': (context) => MainPage(), // 主页路由
'/login': (context) => LoginPage(), // 登录路由
'/cats': (context) => CatsPage(), // 猫咪图库路由
};
}
2.2.6 猫咪API常量配置
- 文件:lib/contents/api_constants.dart
- 代码如下
class ApiConstants {
// 猫咪API
static const String catBaseUrl = 'https://api.thecatapi.com/v1';
static const String catImagesEndpoint = '/images/search';
// 默认配置
static const int defaultPageSize = 10;
static const int defaultTimeout = 15; // 秒
}
2.2.7 封装Dio网络请求
- 文件:lib/utils/http_util.dart
- 代码如下
import 'package:dio/dio.dart';
class HttpUtil {
static final HttpUtil _instance = HttpUtil._internal();
late Dio _dio;
factory HttpUtil() => _instance;
HttpUtil._internal() {
_dio = Dio(BaseOptions(
connectTimeout: const Duration(seconds: 15),
receiveTimeout: const Duration(seconds: 15),
));
}
Dio get dio => _dio;
// 通用GET请求
Future<dynamic> get(String endpoint, {Map<String, dynamic>? queryParams}) async {
try {
final response = await _dio.get(endpoint, queryParameters: queryParams);
return response.data;
} on DioException catch (e) {
throw _handleError(e);
}
}
String _handleError(DioException e) {
switch (e.type) {
case DioExceptionType.connectionTimeout:
case DioExceptionType.sendTimeout:
case DioExceptionType.receiveTimeout:
return '网络连接超时,请检查网络';
case DioExceptionType.badResponse:
return '服务器错误: ${e.response?.statusCode}';
case DioExceptionType.cancel:
return '请求已取消';
default:
return '网络错误: ${e.message}';
}
}
}
2.2.8 状态管理
- 文件:lib/stores/cat_store.dart
- 代码如下
import 'package:flutter/material.dart';
import 'package:app1/api/cat_api.dart';
import 'package:app1/viewmodels/cat_model.dart';
class CatStore extends ChangeNotifier {
List<CatModel> _cats = [];
bool _isLoading = false;
String? _error;
int _currentPage = 1;
List<CatModel> get cats => _cats;
bool get isLoading => _isLoading;
String? get error => _error;
int get currentPage => _currentPage;
// 获取猫咪图片
Future<void> fetchCats({
int limit = 10,
bool hasBreeds = false,
bool loadMore = false,
}) async {
if (!loadMore) {
_currentPage = 1;
}
_isLoading = true;
_error = null;
notifyListeners();
try {
final newCats = await CatApi.getCatImages(
limit: limit,
page: _currentPage,
hasBreeds: hasBreeds,
);
if (loadMore) {
_cats.addAll(newCats);
} else {
_cats = newCats;
}
_currentPage++;
} catch (e) {
_error = e.toString();
} finally {
_isLoading = false;
notifyListeners();
}
}
// 刷新数据
Future<void> refresh() async {
await fetchCats(limit: _cats.length);
}
// 清空数据
void clear() {
_cats = [];
_error = null;
_currentPage = 1;
notifyListeners();
}
}
2.2.9 App入口主页
- 文件:lib/pages/Main/index.dart
- 代码如下
import 'package:flutter/material.dart';
class MainPage extends StatelessWidget {
const MainPage({super.key});
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Qing Mall'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text(
'欢迎使用 Qing Mall',
style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
),
const SizedBox(height: 40),
// 猫咪图库入口
SizedBox(
width: 200,
child: ElevatedButton.icon(
onPressed: () {
Navigator.pushNamed(context, '/cats');
},
icon: const Icon(Icons.pets),
label: const Text('猫咪图库'),
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(vertical: 16),
),
),
),
const SizedBox(height: 16),
// 登录入口
SizedBox(
width: 200,
child: OutlinedButton(
onPressed: () {
Navigator.pushNamed(context, '/login');
},
child: const Text('用户登录'),
),
),
],
),
),
);
}
}
2.2.10 登录页面
- 文件:lib/pages/Login/index.dart
(登录页面的空壳子,有页面结构但需要填充具体登录功能) - 代码如下
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
class LoginPage extends StatefulWidget {
const LoginPage({super.key});
State<LoginPage> createState() => _LoginPageState();
}
class _LoginPageState extends State<LoginPage> {
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('登录'),),
body: Center(child: Text('登录页面'),),
);
}
}
2.2.11 主程序入口文件
- 文件:lib/main.dart
- 代码如下
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:app1/routes/index.dart';
import 'package:app1/stores/cat_store.dart';
void main() {
runApp(
MultiProvider(
providers: [
ChangeNotifierProvider(create: (_) => CatStore()),
// 可以添加更多Provider
],
child: getRootWidget(),
),
);
}
2.2.12 lib目录
现在的lib目录大概是这样的
3.运行项目
鸿蒙
打开DevEco Studio,点击对应的ohos文件,选择模拟器运行如图
安卓
点击绿色三角形进行运行即可
总结
今天从零开始构建一个Flutter鸿蒙项目的完整过程,使用Dio库实现网络请求,调用猫咪图片API,并展示在鸿蒙和安卓双平台上,虽然是参照的网上的各种教程,但是还是感觉有些收获的。
欢迎加入开源鸿蒙跨平台社区:
https://openharmonycrossplatform.csdn.net
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