使用Firebase实现用户登录时持续触发ApiException:8错误排查

我在实现Firebase Google登录功能时，始终触发ApiException:8错误，已排查多项常见问题仍未解决，恳请帮忙分析原因并提供解决办法。

已完成的排查项 #

• google-services.json文件已被正确识别
• 各项值/ID与Firebase项目配置完全匹配
• 模拟器设备已登录个人Gmail账号
• 网络连接正常
• 已将~/.android/debug.keystore中的SHA-1和SHA-256添加至Firebase
• 已执行重建/清理缓存操作

登录方法代码 #

private fun signIn() {

    val gso = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
        .requestIdToken(getString(R.string.default_web_client_id))
        .requestEmail()
        .build()
    val googleSignInClient = GoogleSignIn.getClient(this, gso)
    val signInIntent = googleSignInClient.signInIntent

    val task = GoogleSignIn.getSignedInAccountFromIntent(signInIntent)

    try {
        val auth = Firebase.auth
        // Authenticate with Firebase using Google credentials
        val account = task.getResult(ApiException::class.java)
        val credential = GoogleAuthProvider.getCredential(account?.idToken, null)
        auth.signInWithCredential(credential)
            .addOnCompleteListener(this) { task ->
                if (task.isSuccessful) {
                    // User is logged in, obtain JWT token and return to calling activity
                    val user = auth.currentUser
                    user?.getIdToken(true)?.addOnSuccessListener { result ->
                        val token = result.token
                        val resultIntent = Intent()
                        Timber.i(String.format("Logged in; Token %s", token))
                        resultIntent.putExtra("jwt_token", token)
                        setResult(Activity.RESULT_OK, resultIntent)
                        finish()
                    }
                } else {
                    // Authentication failed, show error message
                    Toast.makeText(this, "Authentication failed.", Toast.LENGTH_SHORT).show()
                }
            }
    } catch (e: ApiException) {
        Timber.e(e);
        // Google Sign-In failed, show error message
        Toast.makeText(this, "Google sign-in failed.", Toast.LENGTH_SHORT).show()
    }
}

错误日志 #

com.google.android.gms.common.api.ApiException: 8: 
    at com.google.android.gms.common.internal.ApiExceptionUtil.fromStatus(com.google.android.gms:play-services-base@@18.0.1:3)
    at com.google.android.gms.auth.api.signin.GoogleSignIn.getSignedInAccountFromIntent(com.google.android.gms:play-services-auth@@20.5.0:3)
    at com.myapp.android.LoginActivity.signIn(LoginActivity.kt:45)
    at com.myapp.android.LoginActivity.onCreate$lambda$0(LoginActivity.kt:32)

App模块build.gradle配置 #

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    id 'com.google.gms.google-services'
}

android {
    namespace 'com.myapp.android'
    compileSdk 33

    defaultConfig {
        applicationId "com.myapp.android"
        minSdk 26
        targetSdk 33
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        vectorDrawables {
            useSupportLibrary true
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
    buildFeatures {
        compose true
    }
    composeOptions {
        kotlinCompilerExtensionVersion '1.4.0'
    }
    packagingOptions {
        resources {
            excludes += '/META-INF/{AL2.0,LGPL2.1}'
        }
    }
}

dependencies {

    // Firebase
    implementation platform('com.google.firebase:firebase-bom:31.5.0')
    implementation 'com.google.firebase:firebase-auth-ktx'
    implementation 'com.google.android.gms:play-services-auth:20.5.0'

    // Logging
    implementation 'com.jakewharton.timber:timber:5.0.1'

    implementation 'androidx.core:core-ktx:1.10.0'
    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.6.1'
    implementation 'androidx.activity:activity-compose:1.7.1'
    implementation platform('androidx.compose:compose-bom:2022.10.00')
    implementation 'androidx.compose.ui:ui'
    implementation 'androidx.compose.ui:ui-graphics'
    implementation 'androidx.compose.ui:ui-tooling-preview'
    implementation 'androidx.compose.material3:material3'
    implementation 'androidx.core:core-ktx:1.10.0'

    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
    androidTestImplementation platform('androidx.compose:compose-bom:2022.10.00')
    androidTestImplementation 'androidx.compose.ui:ui-test-junit4'
    debugImplementation 'androidx.compose.ui:ui-tooling'
    debugImplementation 'androidx.compose.ui:ui-test-manifest'
}

项目根目录build.gradle配置 #

buildscript {
    ext {
        kotlin_version = '1.8.0'
    }
    repositories {
        // Make sure that you have the following two repositories
        google()  // Google's Maven repository
        mavenCentral()  // Maven Central repository
    }
    dependencies {
        // Add the dependency for the Google services Gradle plugin
        classpath 'com.google.gms:google-services:4.3.15'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
    id 'com.android.application' version '8.0.0' apply false
    id 'com.android.library' version '8.0.0' apply false
    id 'org.jetbrains.kotlin.android' version '1.8.0' apply false
}

问题原因与解决办法 #

ApiException:8对应SIGN_IN_FAILED，核心问题出在登录流程的实现逻辑错误：

1. 错误核心点 #

当前代码直接创建signInIntent后就调用GoogleSignIn.getSignedInAccountFromIntent(signInIntent)，但这个方法是用来处理登录返回结果的，而非直接触发登录。正确流程应该是启动登录Activity获取返回结果，再在回调中处理返回的Intent。

2. 修复后的代码实现 #

方案一：使用ActivityResultLauncher（推荐，适配Jetpack Compose）

// 在Activity的onCreate中初始化Launcher
private val googleSignInLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
    if (result.resultCode == Activity.RESULT_OK) {
        val task = GoogleSignIn.getSignedInAccountFromIntent(result.data)
        try {
            val account = task.getResult(ApiException::class.java)
            val credential = GoogleAuthProvider.getCredential(account?.idToken, null)
            Firebase.auth.signInWithCredential(credential)
                .addOnCompleteListener(this) { authTask ->
                    if (authTask.isSuccessful) {
                        val user = Firebase.auth.currentUser
                        user?.getIdToken(true)?.addOnSuccessListener { tokenResult ->
                            val token = tokenResult.token
                            val resultIntent = Intent()
                            Timber.i("Logged in; Token %s", token)
                            resultIntent.putExtra("jwt_token", token)
                            setResult(Activity.RESULT_OK, resultIntent)
                            finish()
                        }
                    } else {
                        Toast.makeText(this, "Authentication failed.", Toast.LENGTH_SHORT).show()
                    }
                }
        } catch (e: ApiException) {
            Timber.e(e)
            Toast.makeText(this, "Google sign-in failed.", Toast.LENGTH_SHORT).show()
        }
    }
}

// 修改signIn方法
private fun signIn() {
    val gso = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
        .requestIdToken(getString(R.string.default_web_client_id))
        .requestEmail()
        .build()
    val googleSignInClient = GoogleSignIn.getClient(this, gso)
    googleSignInLauncher.launch(googleSignInClient.signInIntent)
}

方案二：传统onActivityResult方式

private fun signIn() {
    val gso = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
        .requestIdToken(getString(R.string.default_web_client_id))
        .requestEmail()
        .build()
    val googleSignInClient = GoogleSignIn.getClient(this, gso)
    startActivityForResult(googleSignInClient.signInIntent, RC_SIGN_IN)
}

companion object {
    private const val RC_SIGN_IN = 1001
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    if (requestCode == RC_SIGN_IN) {
        val task = GoogleSignIn.getSignedInAccountFromIntent(data)
        try {
            val account = task.getResult(ApiException::class.java)
            val credential = GoogleAuthProvider.getCredential(account?.idToken, null)
            Firebase.auth.signInWithCredential(credential)
                .addOnCompleteListener(this) { authTask ->
                    if (authTask.isSuccessful) {
                        val user = Firebase.auth.currentUser
                        user?.getIdToken(true)?.addOnSuccessListener { tokenResult ->
                            val token = tokenResult.token
                            val resultIntent = Intent()
                            Timber.i("Logged in; Token %s", token)
                            resultIntent.putExtra("jwt_token", token)
                            setResult(Activity.RESULT_OK, resultIntent)
                            finish()
                        }
                    } else {
                        Toast.makeText(this, "Authentication failed.", Toast.LENGTH_SHORT).show()
                    }
                }
        } catch (e: ApiException) {
            Timber.e(e)
            Toast.makeText(this, "Google sign-in failed.", Toast.LENGTH_SHORT).show()
        }
    }
}

3. 额外验证项 #

• 确认default_web_client_id是Firebase控制台中Web应用的客户端ID，而非Android应用的客户端ID
• 检查Firebase控制台中是否启用了Google登录提供商（Authentication > Sign-in method > Google > 启用）
• 若使用模拟器，确保Google Play服务版本是最新的，可通过Google Play商店更新

内容的提问来源于stack exchange，提问作者Stefan Falk