Flutter集成Firebase遇编译错误，寻求技术帮助

问题背景 #

Flutter新手集成Firebase时，已完成google-services.json放置、Gradle配置，但编译出现两个核心错误：

• Kotlin版本不兼容：依赖库编译使用Kotlin 1.9.0元数据，项目预期版本为1.7.1
• Dex方法数超限：方法总数71748＞65536，超出单个Dex文件的方法数限制

原配置代码 #

android/build.gradle #

plugins{
    id("com.google.gms.google-services") version "4.4.1" apply false
}

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

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

tasks.register("clean", Delete) {
    delete rootProject.buildDir
}

app/build.gradle #

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

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

android {
    namespace "com.example.classico"
    compileSdk flutter.compileSdkVersion
    ndkVersion flutter.ndkVersion

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        applicationId "com.example.classico"
        minSdkVersion flutter.minSdkVersion
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

    buildTypes {
        release {
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation(platform("com.google.firebase:firebase-bom:32.8.1"))
    implementation("com.google.firebase:firebase-analytics")
}

完整错误信息 #

Launching lib\main.dart on sdk gphone x86 in debug mode...
Running Gradle task 'assembleDebug'...
e: C:/Users/Administrator/.gradle/caches/transforms-3/0b7d9e2f04d0deb06f03473cb471b358/transformed/jetified-play-services-measurement-api-21.6.2-api.jar!/META-INF/java.com.google.android.gmscore.integ.client.measurement_api_measurement_api.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.9.0, expected version is 1.7.1.
ERROR:D8: Cannot fit requested classes in a single dex file (# methods: 71748 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
- What went wrong:
Execution failed for task ':app:compileDebugKotlin'.

> A failure occurred while executing org.jetbrains.kotlin.compilerRunner.GradleCompilerRunnerWithWorkers$GradleKotlinCompilerWorkAction
Compilation error. See log for more details

- Try:
Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
Run with --scan to get full insights.

2: Task failed with an exception.
- What went wrong:
Execution failed for task ':app:mergeExtDexDebug'.

> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingTaskDelegate
There was a failure while executing work items
> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingWorkAction
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.

- Try:
Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
Run with --scan to get full insights.

- Get more help at https://help.gradle.org

BUILD FAILED in 4s

┌─ Flutter Fix ──────────────────────────────────────────────────────────────────────────────┐
│ [!] Your project requires a newer version of the Kotlin Gradle plugin.                     │
│ Find the latest version on https://kotlinlang.org/docs/releases.html#release-details, then │
│ update C:\Users\Administrator\Desktop\Flutter Projects\classico\android\build.gradle:      │
│ ext.kotlin_version = ''                                                    │
└────────────────────────────────────────────────────────────────────────────────────────────┘
Error: Gradle task assembleDebug failed with exit code 1

解决方案 #

1. 升级Kotlin版本 #

修改android/build.gradle，添加与Firebase依赖兼容的Kotlin版本（示例用1.9.20，匹配报错中的1.9.0元数据版本）：

plugins{
    id "com.android.application" apply false
    id "kotlin-android" version "1.9.20" apply false
    id("com.google.gms.google-services") version "4.4.1" apply false
}

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

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

tasks.register("clean", Delete) {
    delete rootProject.buildDir
}

2. 启用Multidex #

修改app/build.gradle，在默认配置中开启Multidex并添加依赖：

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

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

android {
    namespace "com.example.classico"
    compileSdk flutter.compileSdkVersion
    ndkVersion flutter.ndkVersion

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        applicationId "com.example.classico"
        minSdkVersion flutter.minSdkVersion
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        // 启用Multidex
        multiDexEnabled true
    }

    buildTypes {
        release {
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation(platform("com.google.firebase:firebase-bom:32.8.1"))
    implementation("com.google.firebase:firebase-analytics")
    // 添加Multidex依赖
    implementation "androidx.multidex:multidex:2.0.1"
}

3. 清理缓存并重新构建 #

执行以下命令清除项目缓存后重新运行：

flutter clean
flutter pub get
flutter run

内容的提问来源于stack exchange，提问作者James john