Flutter云端数据库管理插件agconnect_clouddb的使用
Flutter云端数据库管理插件agconnect_clouddb的使用
简介
Cloud DB 是一种设备与云协同工作的数据库产品，提供了设备与云之间的数据协同管理能力、统一的数据模型以及各种数据管理API。
安装插件
在 Flutter 项目的 pubspec.yaml 文件中添加依赖项：
dependencies:
agconnect_clouddb: ^1.9.0+300
然后在终端运行以下命令以添加依赖项：
flutter pub get
更多详细信息，请参阅开始使用 Flutter。
开发指南
使用
您可以访问 此处 获取更多使用信息。
参考
您可以访问 此处 获取更多引用信息。
许可证
Cloud DB 插件的许可证为：Apache License, version 2.0。
完整示例代码
以下是一个完整的示例代码，展示了如何使用 agconnect_clouddb 插件进行基本操作。
/*
* Copyright (c) 2021-2023. Huawei Technologies Co., Ltd. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import 'dart:async';
import 'package:agconnect_auth/agconnect_auth.dart';
import 'package:agconnect_clouddb/agconnect_clouddb.dart';
import 'package:flutter/material.dart';
void main() {
runApp(_App());
}
class _App extends StatelessWidget {
[@override](/user/override)
Widget build(BuildContext context) {
return MaterialApp(
home: _Home(),
);
}
}
class _Home extends StatefulWidget {
[@override](/user/override)
_HomeState createState() => _HomeState();
}
class _HomeState extends State<_Home> {
final String _zoneName = 'demo';
final String _objectTypeName = 'BookInfo';
AGConnectCloudDBZone? _zone;
String? _currentUserUid;
StreamSubscription<AGConnectCloudDBZoneSnapshot?>? _snapshotSubscription;
StreamSubscription<String?>? _onEvent;
StreamSubscription<bool?>? _onDataEncryptionKeyChanged;
bool _isBusy = false;
[@override](/user/override)
void initState() {
super.initState();
WidgetsBinding.instance.addPostFrameCallback((_) async {
try {
await _initCurrentUser();
await AGConnectCloudDB.getInstance().initialize();
await AGConnectCloudDB.getInstance().createObjectType();
_onEvent = AGConnectCloudDB.getInstance().onEvent().listen((String? event) {
_showDialog(context, 'On Event: $event');
});
_onDataEncryptionKeyChanged = AGConnectCloudDB.getInstance()
.onDataEncryptionKeyChanged()
.listen((bool? data) {
_showDialog(context, 'Data Encryption Key Changed: $data');
});
} catch (e) {
_showDialog(context, 'ERROR', e is FormatException ? e.message : e);
}
});
}
[@override](/user/override)
void dispose() {
_snapshotSubscription?.cancel();
_onEvent?.cancel();
_onDataEncryptionKeyChanged?.cancel();
super.dispose();
}
Future<void> _initCurrentUser() async {
final AGCUser? currentUser = await AGCAuth.instance.currentUser;
if (currentUser != null) {
setState(() => _currentUserUid = currentUser.uid);
} else {
final SignInResult signInResult = await AGCAuth.instance.signInAnonymously();
if (signInResult.user != null) {
setState(() => _currentUserUid = signInResult.user?.uid);
} else {
setState(() => _currentUserUid = '???');
}
}
}
void _showDialog(BuildContext context, String title, [dynamic content]) {
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text(title),
content: content == null
? null
: SingleChildScrollView(
physics: const BouncingScrollPhysics(),
child: Text('$content'),
),
actions: [
TextButton(
onPressed: () {
Navigator.of(context).pop();
},
child: const Text("Close"),
),
],
);
},
);
}
[@override](/user/override)
Widget build(BuildContext context) {
return Stack(
children: <Widget>[
Scaffold(
appBar: AppBar(
title: const Text("AGC Cloud DB Demo"),
actions: <Widget>[
IconButton(
icon: const Icon(Icons.refresh),
onPressed: () async {
setState(() => _isBusy = true);
await AGCAuth.instance.signOut();
setState(() => _currentUserUid = null);
await _initCurrentUser();
setState(() => _isBusy = false);
},
),
],
),
body: Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Padding(
padding: const EdgeInsets.all(16),
child: Text('UserID: $_currentUserUid'),
),
Expanded(
child: ListView(
padding: const EdgeInsets.all(16),
physics: const BouncingScrollPhysics(),
children: <Widget>[
_buildGroup(
children: <Widget>[
_buildButton(
text: 'openCloudDBZone',
onTap: () async {
if (_zone != null) {
throw FormatException(
'Zone object is not null. First try close zone.',
_zone);
}
_zone = await AGConnectCloudDB.getInstance()
.openCloudDBZone(
zoneConfig: AGConnectCloudDBZoneConfig(
zoneName: _zoneName),
);
},
),
_buildButton(
text: 'openCloudDBZone2',
onTap: () async {
if (_zone != null) {
throw FormatException(
'Zone object is not null. First try close zone.',
_zone);
}
_zone = await AGConnectCloudDB.getInstance()
.openCloudDBZone2(
zoneConfig: AGConnectCloudDBZoneConfig(
zoneName: _zoneName),
);
},
),
_buildButton(
text: 'closeCloudDBZone',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
await AGConnectCloudDB.getInstance()
.closeCloudDBZone(zone: _zone!);
_zone = null;
},
),
_buildButton(
text: 'deleteCloudDBZone',
onTap: () async =>
await AGConnectCloudDB.getInstance()
.deleteCloudDBZone(zoneName: _zoneName),
),
],
),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'getCloudDBZoneConfig',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.getCloudDBZoneConfig();
},
),
_buildButton(
text: 'getCloudDBZoneConfigs',
onTap: () async =>
await AGConnectCloudDB.getInstance()
.getCloudDBZoneConfigs(),
),
],
),
const Divider(height: 32),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'enableNetwork',
onTap: () async =>
await AGConnectCloudDB.getInstance()
.enableNetwork(zoneName: _zoneName),
),
_buildButton(
text: 'disableNetwork',
onTap: () async =>
await AGConnectCloudDB.getInstance()
.disableNetwork(zoneName: _zoneName),
),
],
),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'setUserKey',
onTap: () async =>
await AGConnectCloudDB.getInstance().setUserKey(
userKey: '123456789', userReKey: ''),
),
_buildButton(
text: 'updateDataEncryptionKey',
onTap: () async =>
await AGConnectCloudDB.getInstance()
.updateDataEncryptionKey(),
),
],
),
const Divider(height: 32),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'subscribeSnapshot',
onTap: () async {
if (_snapshotSubscription == null) {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
final Stream<AGConnectCloudDBZoneSnapshot?>
stream = await _zone!.subscribeSnapshot(
query: AGConnectCloudDBQuery(_objectTypeName)
..equalTo('id', 2),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
_snapshotSubscription = stream.listen(
(AGConnectCloudDBZoneSnapshot? snapshot) {
_showDialog(
context, 'subscribeSnapshot', snapshot);
});
}
},
),
_buildButton(
text: 'removeSnapshot',
onTap: () async =>
_snapshotSubscription
?.cancel()
.then((_) => _snapshotSubscription = null),
),
],
),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'executeUpsert',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
final int count = await _zone!.executeUpsert(
objectTypeName: _objectTypeName,
entries: <Map<String, dynamic>>[
<String, dynamic>{
'id': 1,
'bookName': 'Book Name - 1',
'price': 14.80,
},
<String, dynamic>{
'id': 2,
'bookName': 'Book Name - 2',
'price': 22.99,
},
<String, dynamic>{
'id': 3,
'bookName': 'Book Name - 3',
'price': 5.60,
},
],
);
return '$count objects successfully written.';
},
),
_buildButton(
text: 'executeDelete',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
final int count = await _zone!.executeDelete(
objectTypeName: _objectTypeName,
entries: <Map<String, dynamic>>[
<String, dynamic>{
'id': 2,
},
],
);
return '$count objects successfully deleted.';
},
),
_buildButton(
text: 'runTransaction',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
await _zone!.runTransaction(
transaction: AGConnectCloudDBTransaction()
..executeUpsert(
objectTypeName: _objectTypeName,
entries: <Map<String, dynamic>>[
<String, dynamic>{
'id': 10,
'bookName': 'Book_10',
'price': 5.10,
},
<String, dynamic>{
'id': 20,
'bookName': 'Book_20',
'price': 25.20,
},
],
)
..executeDelete(
objectTypeName: _objectTypeName,
entries: <Map<String, dynamic>>[
<String, dynamic>{
'id': 10,
},
],
),
);
},
),
],
),
const Divider(height: 32),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'executeQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeQuery(
query: AGConnectCloudDBQuery(_objectTypeName)
..orderBy('price'),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeQueryUnsynced',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeQueryUnsynced(
query: AGConnectCloudDBQuery(_objectTypeName)
..orderBy('price'),
);
},
),
],
),
_buildGroup(
children: <Widget>[
_buildButton(
text: 'executeCountQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeCountQuery(
field: 'price',
query: AGConnectCloudDBQuery(_objectTypeName),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeSumQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeSumQuery(
field: 'price',
query: AGConnectCloudDBQuery(_objectTypeName),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeAverageQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeAverageQuery(
field: 'price',
query: AGConnectCloudDBQuery(_objectTypeName),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeMinimalQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeMinimalQuery(
field: 'price',
query: AGConnectCloudDBQuery(_objectTypeName),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeMaximumQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeMaximumQuery(
field: 'price',
query: AGConnectCloudDBQuery(_objectTypeName),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT,
);
},
),
_buildButton(
text: 'executeServerStatusQuery',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeServerStatusQuery();
},
),
_buildButton(
text: 'executeGreaterThan',
onTap: () async {
if (_zone == null) {
throw FormatException(
'Zone object is null. First try open zone.',
_zone);
}
return await _zone!.executeQuery(
query: AGConnectCloudDBQuery(_objectTypeName)
..greaterThan('price', 10),
policy: AGConnectCloudDBZoneQueryPolicy
.POLICY_QUERY_DEFAULT);
},
),
],
),
],
),
),
],
),
),
if (_isBusy)
Container(
color: Colors.black87,
alignment: Alignment.center,
child: const CircularProgressIndicator(),
),
],
);
}
Widget _buildGroup({
required List<Widget> children,
}) {
return Container(
padding: const EdgeInsets.all(16),
margin: const EdgeInsets.only(top: 8, bottom: 8),
decoration: const BoxDecoration(
color: Colors.black12,
borderRadius: BorderRadius.all(Radius.circular(16)),
),
child: Wrap(
spacing: 8,
runSpacing: 8,
alignment: WrapAlignment.center,
crossAxisAlignment: WrapCrossAlignment.center,
children: children,
),
);
}
Widget _buildButton({
required String text,
required Future<dynamic> Function() onTap,
}) {
return ElevatedButton(
child: Text(
text,
textAlign: TextAlign.center,
),
onPressed: () async {
try {
setState(() => _isBusy = true);
final dynamic result = await onTap();
_showDialog(context, 'SUCCESS', result);
} catch (e) {
_showDialog(context, 'ERROR', e.toString());
} finally {
setState(() => _isBusy = false);
}
},
);
}
}
更多关于Flutter云端数据库管理插件agconnect_clouddb的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html
1 回复
更多关于Flutter云端数据库管理插件agconnect_clouddb的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
agconnect_clouddb 是华为提供的用于 Flutter 应用的云端数据库管理插件，它允许开发者轻松地将数据存储在华为云数据库，并实现数据的增删改查等操作。以下是使用 agconnect_clouddb 插件的基本步骤和示例代码。
1. 环境准备
在开始之前，请确保你已经完成了以下准备工作：
- 安装 Flutter SDK。
- 在华为开发者联盟注册并创建应用，获取
agconnect-services.json文件。 - 在
pubspec.yaml中添加agconnect_clouddb依赖。
2. 添加依赖
在 pubspec.yaml 文件中添加 agconnect_clouddb 依赖：
dependencies:
flutter:
sdk: flutter
agconnect_clouddb: ^1.4.0+300
然后运行 flutter pub get 安装依赖。
3. 配置 agconnect-services.json
将下载的 agconnect-services.json 文件放置在 android/app 目录下。
4. 初始化 Huawei Mobile Services (HMS)
在 main.dart 中初始化 HMS：
import 'package:agconnect_clouddb/agconnect_clouddb.dart';
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await AGCCloudDB.init();
runApp(MyApp());
}
5. 创建对象类型
在华为云数据库中，你需要定义对象类型（Object Type）。每个对象类型对应一个表，表中的字段对应对象的属性。
class Book {
String id;
String title;
String author;
Book({required this.id, required this.title, required this.author});
Map<String, dynamic> toMap() {
return {
'id': id,
'title': title,
'author': author,
};
}
factory Book.fromMap(Map<String, dynamic> map) {
return Book(
id: map['id'],
title: map['title'],
author: map['author'],
);
}
}
6. 创建对象类型定义
使用 AGCCloudDBZoneSchema 和 AGCCloudDBFieldSchema 定义对象类型：
final schema = AGCCloudDBZoneSchema('Book', '1.0.0', [
AGCCloudDBFieldSchema('id', AGCCloudDBFieldType.TEXT, isPrimaryKey: true),
AGCCloudDBFieldSchema('title', AGCCloudDBFieldType.TEXT),
AGCCloudDBFieldSchema('author', AGCCloudDBFieldType.TEXT),
]);
7. 创建云数据库区域
创建云数据库区域（Zone），用于管理数据：
final zone = AGCCloudDBZone('MyZone');
await AGCCloudDB.createZone(zone);
8. 执行增删改查操作
以下是一些基本的增删改查操作示例：
插入数据
final book = Book(id: '1', title: 'Flutter Guide', author: 'John Doe');
await AGCCloudDB.executeUpsert(zone, schema, [book.toMap()]);
查询数据
final query = AGCCloudDBQueryBuilder(schema)
.where(AGCCloudDBQueryCondition.equal('id', '1'))
.build();
final result = await AGCCloudDB.executeQuery(zone, query);
final books = result.map((map) => Book.fromMap(map)).toList();
更新数据
final updatedBook = Book(id: '1', title: 'Flutter Advanced Guide', author: 'John Doe');
await AGCCloudDB.executeUpsert(zone, schema, [updatedBook.toMap()]);
删除数据
final query = AGCCloudDBQueryBuilder(schema)
.where(AGCCloudDBQueryCondition.equal('id', '1'))
.build();
await AGCCloudDB.executeDelete(zone, query);
9. 删除云数据库区域
当你不再需要某个云数据库区域时，可以将其删除：
await AGCCloudDB.deleteZone(zone);
10. 错误处理
在执行数据库操作时，建议使用 try-catch 进行错误处理：
try {
await AGCCloudDB.executeUpsert(zone, schema, [book.toMap()]);
} catch (e) {
print('Error: $e');
}