Flutter Android Studio无法连接Cloud Firestore后端问题求助

控制台报错信息 #

W/Firestore(26053): (24.2.2) [OnlineStateTracker]: Could not reach Cloud Firestore backend. Backend didn't respond within 10 seconds
W/Firestore(26053): 
W/Firestore(26053): This typically indicates that your device does not have a healthy Internet connection at the moment. The client will operate in offline mode until it is able to successfully connect to the backend.
E/flutter (26053): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: [cloud_firestore/unavailable] The service is currently unavailable. This is a most likely a transient condition and may be corrected by retrying with a backoff.
E/flutter (26053): #0      checkIfDocExists (package:crypto_app/Functions/firestorehelper.dart:29:5)
E/flutter (26053): <asynchronous suspension>
E/flutter (26053): #1      _MainPagesState._checkUsername (package:crypto_app/UI/mainpages.dart:63:21)
E/flutter (26053): <asynchronous suspension>
E/flutter (26053): 
W/Firestore(26053): (24.2.2) [WatchStream]: (a4a9ed6) Stream closed with status: Status{code=UNAVAILABLE, description=Channel shutdownNow invoked, cause=null}.

已尝试的解决方法 #

• 在3个AndroidManifest.xml文件中添加<uses-permission android:name="android.permission.INTERNET" />
• 在主目录下的AndroidManifest.xml中添加<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
• 启用Multidex
• 更换WiFi网络
• 次日重试仍存在相同问题
• 最低SDK版本设置为21
• 将代码复制到全新项目中测试

Firebase初始化相关 #

主函数代码

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(
    name: 'Retrospect',
    options: DefaultFirebaseOptions.currentPlatform,
  );

  runApp(MyApp());
}

初始化时控制台警告

I/FirebaseApp(26053): Device unlocked: initializing all Firebase APIs for app Retrospect
I/flutter (26053): Refreshing
W/DynamiteModule(26053): Local module descriptor class for com.google.android.gms.providerinstaller.dynamite not found.
I/DynamiteModule(26053): Considering local module com.google.android.gms.providerinstaller.dynamite:0 and remote module com.google.android.gms.providerinstaller.dynamite:0
W/ProviderInstaller(26053): Failed to load providerinstaller module: No acceptable module com.google.android.gms.providerinstaller.dynamite found. Local version is 0 and remote version is 0.

项目配置详情 #

pubspec.yaml 依赖

dependencies:
  flutter:
    sdk: flutter


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  firebase_core: ^1.20.1
  cloud_firestore: ^3.4.4
  http: ^0.13.4
  path_provider: ^2.0.11
  get_storage: ^2.0.3

app/build.gradle 配置

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'com.google.gms.google-services'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation "com.android.support:multidex:1.0.3"
    implementation 'com.google.android.material:material:1.6.1'
    implementation 'com.google.android.gms:play-services-ads:21.1.0'
    implementation platform('com.google.firebase:firebase-bom:30.3.2')
    implementation 'com.google.firebase:firebase-analytics-ktx'
    implementation 'com.google.firebase:firebase-storage-ktx'
}

根目录 build.gradle 配置

buildscript {
    ext.kotlin_version = '1.6.10'
    repositories {
        google()
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:7.1.2'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.3.13'
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}

google-services.json 文件位置

Firestore 规则（Python可正常读取，规则无问题）

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if
          request.time < timestamp.date(2022, 12, 12);
    }
  }
}

调用Firestore的函数代码 #

import 'package:cloud_firestore/cloud_firestore.dart';

Future<bool> checkIfDocExists(String docId) async {
  try {
    // Get reference to Firestore collection
    var collectionRef = FirebaseFirestore.instance.collection('accounts');

    var doc = await collectionRef.doc(docId).get();
    return doc.exists;
  } catch (e) {
    throw e;
  }
}

问题 #

完全无法通过Flutter访问Cloud Firestore，未发现Windows Defender或防火墙拦截，请问该错误的原因是什么？

内容的提问来源于stack exchange，提问作者Bill.xby