Google登录及获取Calendar信息

firebase方案（实际是一个三方登录集成，由于是google的所以使用Google账户登录以后可以使用google api）

firebase官网
使用firebase Auth集成并登录
firebase创建项目后会在google cloud中创建并关联项目，登录成功后接着就可以按照下述方法使用google api获取相应信息。

flutter中用到的插件：
firebase_auth
firebase_core
参考firebase flutter网站

在google开发者平台构建项目（单独集成）

进入Google Cloud登录并注册，之后按照提示构建项目。

进入Apis&Services->Credentials下点击CREATE CREDENTIALS创建OAuth 2.0 Client IDs。（ios和android需分别创建）。

创建过程中根据提示android需要配置sha-1签名证书，ios需要配置url scheme。

android需要配置签名:

Android 怎么创建签名文件和解析签名文件

将生成好的签名文件放到工程app文件夹下，与app的build.gradle平行,之后再app的build.gradle中做如下配置:

...
android{...buildTypes {release {signingConfig signingConfigs.debug}debug {signingConfig signingConfigs.debug}}signingConfigs {debug {storeFile file("nearhubone.keystore")//签名文件名storePassword "123456"//密码keyAlias "nearhubone"//别名keyPassword "123456"//密码}release {storeFile file("nearhubone.keystore")storePassword "123456"keyAlias "nearhubone"keyPassword "123456"}}...
}

申请需要使用的api

点击Google Cloud-APIs＆Services下的Enabled APIs&services，enable需要使用的api，如Google Calendar API。需要创建api key的则创建api key（非所有api都需要创建api key）。

集成到对于项目

Flutter中集成

需要使用的插件有：

google_sign_in//用于登录

extension_google_sign_in_as_googleapis_auth//配合拓展google_sign_in用于提供api初始化需要的Client

googleapis//提供丰富的google api

Flutter使用 Google API
Flutter使用 Google API 英文

流程如下：

使用google_sign_in插件实现登录

serverClientId参数填写OAuth 2.0 Client IDs里相对应的ClientId。
注意初始化配置中的scopes，这个scopes用于用户授权范围，只有填入的scopes才会显示在用户授权页上并得到授权，否则api将会调用失败。这个scopes的字段在api文档里可得。如CalendarList get这个api在其文档里的Authorization就可看到scope列表。

登录的示例代码如下:

import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';//登录所需插件
import 'package:http/http.dart' as http;
import 'dart:convert' show json;//配置google登录
GoogleSignIn _googleSignIn = GoogleSignIn(// Optional clientIdserverClientId: '781114075503-2qscj6a0ahsqedt6cellol0ur7qij645.apps.googleusercontent.com',//授权范围（用户授权页会提示用户授权）scopes: <String>['email','https://www.googleapis.com/auth/contacts.readonly','https://www.googleapis.com/auth/calendar',//获取日历信息授权],
);class SignInDemo extends StatefulWidget {const SignInDemo({Key? key}) : super(key: key);@overrideState createState() => SignInDemoState();
}class SignInDemoState extends State<SignInDemo> {GoogleSignInAccount? _currentUser;String _contactText = '';@overridevoid initState() {super.initState();//注册登录回调_googleSignIn.onCurrentUserChanged.listen((GoogleSignInAccount? account) {setState(() {_currentUser = account;});if (_currentUser != null) {_handleGetContact(_currentUser!);}});_googleSignIn.signInSilently();}//【非登录必须流程】登录后获取用户个人信息用于显示    Future<void> _handleGetContact(GoogleSignInAccount user) async {setState(() {_contactText = 'Loading contact info...';});//通过http请求获取用户个人信息final http.Response response = await http.get(Uri.parse('https://people.googleapis.com/v1/people/me/connections''?requestMask.includeField=person.names'),headers: await user.authHeaders,//请求头置入登录成功信息);if (response.statusCode != 200) {setState(() {_contactText = 'People API gave a ${response.statusCode} ''response. Check logs for details.';});print('People API ${response.statusCode} response: ${response.body}');return;}//解析用户信息final Map<String, dynamic> data =json.decode(response.body) as Map<String, dynamic>;final String? namedContact = _pickFirstNamedContact(data);setState(() {if (namedContact != null) {_contactText = 'I see you know $namedContact!';} else {_contactText = 'No contacts to display.';}});}String? _pickFirstNamedContact(Map<String, dynamic> data) {final List<dynamic>? connections = data['connections'] as List<dynamic>?;final Map<String, dynamic>? contact = connections?.firstWhere((dynamic contact) => contact['names'] != null,orElse: () => null,) as Map<String, dynamic>?;if (contact != null) {final Map<String, dynamic>? name = contact['names'].firstWhere((dynamic name) => name['displayName'] != null,orElse: () => null,) as Map<String, dynamic>?;if (name != null) {return name['displayName'] as String?;}}return null;}//登录Future<void> _handleSignIn() async {try {await _googleSignIn.signIn();} catch (error) {print(error);}}//登出Future<void> _handleSignOut() => _googleSignIn.disconnect();//界面展示Widget _buildBody() {final GoogleSignInAccount? user = _currentUser;if (user != null) {return Column(mainAxisAlignment: MainAxisAlignment.spaceAround,children: <Widget>[ListTile(leading: GoogleUserCircleAvatar(identity: user,),title: Text(user.displayName ?? ''),subtitle: Text(user.email),),const Text('Signed in successfully.'),Text(_contactText),ElevatedButton(onPressed: _handleSignOut,child: const Text('SIGN OUT'),),ElevatedButton(child: const Text('REFRESH'),onPressed: () => _handleGetContact(user),),],);} else {return Column(mainAxisAlignment: MainAxisAlignment.spaceAround,children: <Widget>[const Text('You are not currently signed in.'),ElevatedButton(onPressed: _handleSignIn,child: const Text('SIGN IN'),),],);}}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: const Text('Google Sign In'),),body: ConstrainedBox(constraints: const BoxConstraints.expand(),child: _buildBody(),));}
}

参考：
官方示例

获取日历信息

获取日历信息可使用两种方式：

一种方式直接使用http请求，无需其他插件,只需在请求头中添加登录信息
api查看官方文档

import 'package:google_sign_in/google_sign_in.dart';...
class SignInDemo extends State<SignInDemo> {   ...GoogleSignInAccount? _currentUser;@overridevoid initState() {super.initState();//注册登录回调_googleSignIn.onCurrentUserChanged.listen((GoogleSignInAccount? account) {setState(() {_currentUser = account;});...});}...onGetCalendarClick(){handleGetCalendar(_currentUser);}...//获取谷歌日历列表信息（http方式）handleGetCalendar(GoogleSignInAccount user) async {final http.Response response = await http.get(Uri.parse('https://www.googleapis.com/calendar/v3/calendars/primary/events'),//api查看官方文档headers: await user.authHeaders,//在请求头中添加登录信息);if (response.statusCode != 200) {print('Calendar API ${response.statusCode} response: ${response.body}');} else {final Map<String, dynamic> data =json.decode(response.body) as Map<String, dynamic>;debugPrint(data.toString());}}}

【推荐】另一种方式使用googleapis插件配合google登录拓展插件extension_google_sign_in_as_googleapis_auth使用

由于googleapis初始化对应api时需要提供client，extension_google_sign_in_as_googleapis_auth插件可以配合google_sign_in提供client。

代码如下:

import 'package:google_sign_in/google_sign_in.dart';
import 'package:extension_google_sign_in_as_googleapis_auth/extension_google_sign_in_as_googleapis_auth.dart';
import 'package:googleapis/calendar/v3.dart';
//获取谷歌日历列表信息（sdk方式）getCalendarEvent() async {var httpClient = (await _googleSignIn.authenticatedClient())!;var calendar = CalendarApi(httpClient);var calEvents = calendar.events.list("primary");calEvents.then((events) => {events.items?.forEach((event) => print("EVENT ${event.summary}"))});}

参考：
如何在flutter中使用google日历api获取一个月内的所有活动 (仅参考使用googleapis-CalendarApi部分)

获取身份验证后的 HTTP 客户端

完整代码参考：

google_sign_in_get_calendar_demo.dart

import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:extension_google_sign_in_as_googleapis_auth/extension_google_sign_in_as_googleapis_auth.dart';
import 'package:googleapis/calendar/v3.dart';
import 'package:http/http.dart' as http;
import 'dart:convert' show json;//配置google登录
GoogleSignIn _googleSignIn = GoogleSignIn(// Optional clientIdserverClientId: '781114075503-2qscj6a0ahsqedt6cellol0ur7qij645.apps.googleusercontent.com',//授权范围（用户授权页会提示用户授权）scopes: <String>['email','https://www.googleapis.com/auth/contacts.readonly','https://www.googleapis.com/auth/calendar',],
);class SignInDemo extends StatefulWidget {const SignInDemo({Key? key}) : super(key: key);@overrideState createState() => SignInDemoState();
}class SignInDemoState extends State<SignInDemo> {GoogleSignInAccount? _currentUser;String _contactText = '';@overridevoid initState() {super.initState();//注册登录回调_googleSignIn.onCurrentUserChanged.listen((GoogleSignInAccount? account) {setState(() {_currentUser = account;});if (_currentUser != null) {_handleGetContact(_currentUser!);}});_googleSignIn.signInSilently();}//【非登录必须流程】登录后获取用户个人信息用于显示Future<void> _handleGetContact(GoogleSignInAccount user) async {setState(() {_contactText = 'Loading contact info...';});//通过http请求获取用户个人信息final http.Response response = await http.get(Uri.parse('https://people.googleapis.com/v1/people/me/connections''?requestMask.includeField=person.names'),headers: await user.authHeaders,//请求头置入登录成功信息);if (response.statusCode != 200) {setState(() {_contactText = 'People API gave a ${response.statusCode} ''response. Check logs for details.';});print('People API ${response.statusCode} response: ${response.body}');return;}//解析用户信息final Map<String, dynamic> data =json.decode(response.body) as Map<String, dynamic>;final String? namedContact = _pickFirstNamedContact(data);setState(() {if (namedContact != null) {_contactText = 'I see you know $namedContact!';} else {_contactText = 'No contacts to display.';}});}String? _pickFirstNamedContact(Map<String, dynamic> data) {final List<dynamic>? connections = data['connections'] as List<dynamic>?;final Map<String, dynamic>? contact = connections?.firstWhere((dynamic contact) => contact['names'] != null,orElse: () => null,) as Map<String, dynamic>?;if (contact != null) {final Map<String, dynamic>? name = contact['names'].firstWhere((dynamic name) => name['displayName'] != null,orElse: () => null,) as Map<String, dynamic>?;if (name != null) {return name['displayName'] as String?;}}return null;}//登录Future<void> _handleSignIn() async {try {await _googleSignIn.signIn();} catch (error) {print(error);}}//登出Future<void> _handleSignOut() => _googleSignIn.disconnect();//获取谷歌日历列表信息（sdk方式）getCalendarEvent() async {var httpClient = (await _googleSignIn.authenticatedClient())!;var calendar = CalendarApi(httpClient);var calEvents = calendar.events.list("primary");calEvents.then((events) => {events.items?.forEach((event) => print("EVENT ${event.summary}"))});}//获取谷歌日历列表信息（http方式）handleGetCalendar(GoogleSignInAccount user) async {final http.Response response = await http.get(Uri.parse('https://www.googleapis.com/calendar/v3/users/me/calendarList/primary'),//api查看官方文档headers: await user.authHeaders,//在请求头中添加登录信息);if (response.statusCode != 200) {print('Calendar API ${response.statusCode} response: ${response.body}');} else {}}//界面展示Widget _buildBody() {final GoogleSignInAccount? user = _currentUser;if (user != null) {return Column(mainAxisAlignment: MainAxisAlignment.spaceAround,children: <Widget>[ListTile(leading: GoogleUserCircleAvatar(identity: user,),title: Text(user.displayName ?? ''),subtitle: Text(user.email),),const Text('Signed in successfully.'),Text(_contactText),ElevatedButton(onPressed: ()=>handleGetCalendar(user),child: const Text('getCalendarEvent http'),),ElevatedButton(onPressed: getCalendarEvent,child: const Text('getCalendarEvent'),),ElevatedButton(onPressed: _handleSignOut,child: const Text('SIGN OUT'),),ElevatedButton(child: const Text('REFRESH'),onPressed: () => _handleGetContact(user),),],);} else {return Column(mainAxisAlignment: MainAxisAlignment.spaceAround,children: <Widget>[const Text('You are not currently signed in.'),ElevatedButton(onPressed: _handleSignIn,child: const Text('SIGN IN'),),],);}}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: const Text('Google Sign In'),),body: ConstrainedBox(constraints: const BoxConstraints.expand(),child: _buildBody(),));}
}

pubspec.yaml

dependencies:flutter:sdk: flutterflutter_signin_button: ^2.0.0google_sign_in: ^5.1.0extension_google_sign_in_as_googleapis_auth: ^2.0.7googleapis: ^9.2.0googleapis_auth: ^1.3.1url_launcher: ^6.1.5dev_dependencies:flutter_test:sdk: flutterdrive: 1.0.0-1.0.nullsafety.1flutter_driver:sdk: flutterhttp: ^0.13.3flutter_lints: ^2.0.0

其他参考

Flutter: Use Google Calendar API — Adding the events to Calendar

将dart和flutter与Google Calendar API结合使用以获取用户日历上的事件列表