已调用FirebaseApp.initializeApp仍未初始化Default FirebaseApp，使用Firestore报错

针对调用FirebaseApp.initializeApp(Context)后，使用Firestore时仍出现「Default FirebaseApp is not initialized in this process」错误的问题，结合你提供的配置文件，可按以下步骤排查修复：

1. 检查google-services.json配置 #

• 确保文件放在app模块根目录下，而非项目根目录
• 验证文件内package_name与app/build.gradle中applicationId（com.allapps.qrcode）完全一致
• 多环境构建时，确认对应环境的json文件正确配置

2. 统一Firebase依赖版本，消除冲突 #

你的依赖中存在同一服务的版本不一致问题（如firebase-analytics和firebase-analytics-ktx版本不同），推荐使用Firebase BoM统一管理版本：
在app/build.gradle的dependencies块顶部添加：

implementation platform('com.google.firebase:firebase-bom:32.7.0')

然后修改所有Firebase依赖，去掉版本号：

implementation 'com.google.firebase:firebase-analytics-ktx'
implementation 'com.google.firebase:firebase-firestore-ktx'
implementation 'com.google.firebase:firebase-inappmessaging-display'
implementation 'com.google.firebase:firebase-crashlytics-ktx'
implementation 'com.google.firebase:firebase-perf-ktx'

3. 调整Gradle插件应用顺序 #

确保com.google.gms.google-services插件是最后一个应用的，修改app/build.gradle的plugins块：

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'org.jetbrains.kotlin.android'
    id 'com.google.firebase.crashlytics'
    id 'com.google.firebase.firebase-perf'
    id 'com.google.gms.google-services' // 移至最后
}

4. 补充ProGuard规则（仅Release构建） #

你的Release构建开启了代码混淆，需在proguard-rules.pro中添加Firebase相关规则：

# Firebase Core
-keep class com.google.firebase.FirebaseApp { *; }
-keep class com.google.firebase.components.** { *; }
-keep class com.google.firebase.provider.** { *; }

# Firebase Firestore
-keep class com.google.firebase.firestore.** { *; }

5. 规范初始化逻辑 #

• 通常无需手动调用FirebaseApp.initializeApp()，Google Services插件会自动完成初始化，手动调用可能引发冲突
• 若必须手动初始化，确保在自定义Application的onCreate()中最早执行，且仅执行一次：

class MyApp : Application() {
    override fun onCreate() {
        super.onCreate()
        if (FirebaseApp.getApps(this).isEmpty()) {
            FirebaseApp.initializeApp(this)
        }
    }
}

并在AndroidManifest.xml中注册该Application：

<application
    android:name=".MyApp"
    ...>
    <!-- 其他配置 -->
</application>

6. 清理重建项目 #

• 执行Android Studio的File -> Invalidate Caches... -> Invalidate and Restart
• 运行命令行：./gradlew clean build清理构建缓存

你提供的配置文件 #

app/build.gradle

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'org.jetbrains.kotlin.android'
    id 'com.google.gms.google-services'
    id 'com.google.firebase.crashlytics'
    id 'com.google.firebase.firebase-perf'

}

android {
    compileSdk 34
    namespace 'com.x.y'

    defaultConfig {
        applicationId "com.allapps.qrcode"
        minSdk 21
        targetSdk 33
        versionCode 22
        versionName "1.1.10"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        vectorDrawables.useSupportLibrary = true
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation project(path: ':AllAds')
    implementation 'androidx.core:core-ktx:1.9.0'
    implementation 'androidx.appcompat:appcompat:1.6.1'

    implementation 'com.google.android.material:material:1.8.0'
    implementation 'com.google.code.gson:gson:2.9.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    implementation 'com.google.zxing:core:3.4.0'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'com.google.firebase:firebase-analytics:21.2.0'
    implementation 'com.google.firebase:firebase-firestore-ktx:24.4.3'
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.4'
    implementation 'com.google.firebase:firebase-inappmessaging-display:20.3.0'
    implementation 'com.google.firebase:firebase-crashlytics:18.3.5'
    implementation 'com.google.firebase:firebase-perf-ktx:20.3.1'
    implementation 'me.dm7.barcodescanner:zxing:1.9.8'
    implementation 'com.google.firebase:firebase-crashlytics-ktx:18.3.7'
    implementation 'com.google.firebase:firebase-analytics-ktx:21.3.0'

    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

根build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        maven { url "https://jitpack.io" }
        google()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.3.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.20"
        classpath 'com.google.gms:google-services:4.4.0'
        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.9.9'
        classpath 'com.google.firebase:perf-plugin:1.4.2'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

错误日志截图 #

内容的提问来源于stack exchange，提问作者Igor Ronner