Android Google登录并获取token（亲测有效）

背景：

Android 需要用到Google的登录授权，用去token给到服务器，服务器再通过token去获取用户信息，实现第三方登录。

我们通过登录之后的email来获取token，不需要server_clientId；如果用server_clientId还需要在google的控制台配置测试的账号，否则登录的时候会返回错误码10.

实现步骤：

1、 手机或者Pad连接可以访问google的网络

2、最外层的build.gradle增加依赖

dependencies {classpath 'com.google.gms:google-services:4.3.15'
}

app下的build.gradle增加依赖

implementation 'com.google.android.gms:play-services-auth:20.6.0'

3、初始化谷歌服务

val googleSignInOptions = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)

.requestEmail() .build()

//这里不要调用requestIdToken

mGoogleSignInClient = GoogleSignIn.getClient(activity, googleSignInOptions)

4、检查google 服务器是否可用，手机是否有环境

val isGooglePlayServicesAvailable=GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(activity)

5、如果没有环境，返回，流程结束

if (isGooglePlayServicesAvailable!= ConnectionResult.SUCCESS) {// 验证是否已在此设备上安装并启用Google Play服务，以及此设备上安装的旧版本是否为此客户端所需的版本GoogleApiAvailability.getInstance().makeGooglePlayServicesAvailable(activity)return@launchIO
}

6、如果有环境，调用google的登录，调转到第三方app

val signInIntent: Intent = mGoogleSignInClient!!.signInIntent
activity.startActivityForResult(signInIntent,100
)

7、重写Activity的这个方法，然后获取token

fun onActivityResult(requestCode: Int, data: Intent?) {if (requestCode == 100) {

      val completedTask: Task<GoogleSignInAccount> =GoogleSignIn.getSignedInAccountFromIntent(data)
val account: GoogleSignInAccount =completedTask.getResult(ApiException::class.java)
val status: Task<GoogleSignInAccount> = completedTask
if (!status.isSuccessful) {throw Exception(status.exception)
}

Log.d("测试", "account.email: " + account.email)
var loginGoogleRequest = LoginGoogleRequest()
loginGoogleRequest.bizId = CoreConstant.bizId
// Obtain token for access gmail account
var token: String =
    GoogleAuthUtil.getToken(
        CoreVariable.coreApplication,
        account.email!!,
        "oauth2:profile email"
    )
Log.d("测试", "token= " + token)
}