迁移Flutter Gradle插件后，如何修复FirebaseOptions加载失败错误？

错误日志 #

E/flutter ( 6571): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: PlatformException(java.lang.Exception: Failed to load FirebaseOptions from resource. Check that you have defined values.xml correctly., Exception, Cause: null, Stacktrace: java.lang.Exception: Failed to load FirebaseOptions from resource. Check that you have defined values.xml correctly.
E/flutter ( 6571):  at io.flutter.plugins.firebase.core.FlutterFirebaseCorePlugin.lambda$optionsFromResource$4$io-flutter-plugins-firebase-core-FlutterFirebaseCorePlugin(FlutterFirebaseCorePlugin.java:207)
E/flutter ( 6571):  at io.flutter.plugins.firebase.core.FlutterFirebaseCorePlugin$$ExternalSyntheticLambda2.run(Unknown Source:4)
E/flutter ( 6571):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
E/flutter ( 6571):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
E/flutter ( 6571):  at java.lang.Thread.run(Thread.java:1012)
E/flutter ( 6571): , null)
E/flutter ( 6571): #0      FirebaseCoreHostApi.optionsFromResource (package:firebase_core_platform_interface/src/pigeon/messages.pigeon.dart:242:7)
E/flutter ( 6571): <asynchronous suspension>
E/flutter ( 6571): #1      MethodChannelFirebase.initializeApp (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:89:25)
E/flutter ( 6571): <asynchronous suspension>
E/flutter ( 6571): #2      Firebase.initializeApp (package:firebase_core/src/firebase.dart:43:31)

问题背景 #

调用await Firebase.initializeApp();后立即抛出该错误。问题出现在移除已弃用的Flutter Gradle插件imperative apply方式，迁移至新的声明式apply方式之后，创建新项目测试时也遇到相同问题。应用仅针对iOS和Android平台构建，不包含Web平台。环境：firebase_core: ^2.27.1

1. 检查Android端values.xml配置 #

• 打开android/app/src/main/res/values/values.xml文件，确认是否包含完整的Firebase配置参数，格式参考：

  <resources>
      <!-- 其他原有配置 -->
      <string name="firebase_api_key" translatable="false">你的Firebase API密钥</string>
      <string name="firebase_app_id" translatable="false">你的Firebase应用ID</string>
      <string name="firebase_messaging_sender_id" translatable="false">你的消息发送ID</string>
      <string name="firebase_project_id" translatable="false">你的Firebase项目ID</string>
      <string name="firebase_storage_bucket" translatable="false">你的存储桶地址</string>
  </resources>
  

• 若缺少上述参数，从Firebase控制台重新下载google-services.json文件，将其放置在android/app/目录下（声明式Gradle配置仍依赖该文件自动注入配置），或手动提取文件中的对应字段补充到values.xml。

2. 验证Gradle声明式配置正确性 #

• 检查settings.gradle文件，确保插件管理和引入配置正确：

  pluginManagement {
      def flutterSdkPath = {
          def properties = new Properties()
          file("local.properties").withInputStream { properties.load(it) }
          def flutterSdkPath = properties.getProperty("flutter.sdk")
          assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
          return flutterSdkPath
      }
      settings.ext.flutterSdkPath = flutterSdkPath()
  
      includeBuild("${settings.ext.flutterSdkPath}/packages/flutter_tools/gradle")
  
      repositories {
          google()
          mavenCentral()
          gradlePluginPortal()
      }
  }
  
  plugins {
      id "dev.flutter.flutter-plugin-loader" version "1.0.0"
      id "com.android.application" version "7.3.0" apply false
      id "org.jetbrains.kotlin.android" version "1.7.10" apply false
      id "com.google.gms.google-services" version "4.4.0" apply false
  }
  
  include ":app"
  

• 检查android/app/build.gradle文件，确保顶部已应用必要插件：

  plugins {
      id "com.android.application"
      id "kotlin-android"
      id "dev.flutter.flutter-gradle-plugin"
      id "com.google.gms.google-services"
  }
  

3. 手动初始化Firebase（绕过资源加载） #

若配置无误仍报错，可在代码中手动传入FirebaseOptions，替代从资源加载的方式：

import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart'; // 可通过`flutterfire configure`命令生成该文件

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );
  runApp(MyApp());
}

• 若未生成firebase_options.dart，可临时硬编码参数（生产环境不推荐）：

await Firebase.initializeApp(
  options: FirebaseOptions(
    apiKey: "你的Firebase API密钥",
    appId: "你的Firebase应用ID",
    messagingSenderId: "你的消息发送ID",
    projectId: "你的Firebase项目ID",
    storageBucket: "你的存储桶地址",
  ),
);

4. 清理缓存并重建项目 #

执行以下命令清除缓存后重新构建：

flutter clean
cd android && ./gradlew clean
cd .. && flutter pub get
flutter run

内容的提问来源于stack exchange，提问作者sanjay c