执行flutter build appbundle --release时触发:app:minifyReleaseWithR8错误求助

执行flutter build appbundle --release构建发布版App Bundle时，出现如下错误：

FAILURE: Build failed with an exception.
Execution failed for task ':app:minifyReleaseWithR8'.
A failure occurred while executing com.android.build.gradle.internal.tasks.R8Task$R8Runnable
Compilation failed to complete, origin: C:\users_freschissimo_app\build\flutter_geofire\intermediates\runtime_library_classes_jar\release\classes.jar:com/example/users_freschissimo_app/BuildConfig.class

以下是配置文件内容：

app\build.gradle #

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

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

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

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


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


def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

android {
    compileSdkVersion 34
    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'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.freschissimo.usersapp"
        minSdkVersion 27
        targetSdkVersion 33
        versionCode 12 //change it for release
        versionName "1.0" //change it for release
        multiDexEnabled true
    }

    signingConfigs {
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }
    buildTypes {
        release {
            signingConfig signingConfigs.release
        }
    }

    namespace "com.example.users_freschissimo_app"
}

flutter {
    source '../..'
}

dependencies {
    implementation 'com.facebook.android:facebook-android-sdk:5.15.3'
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation "com.android.support:multidex:1.0.1"
    implementation 'com.stripe:stripe-android:17.1.1'
    implementation platform('com.google.firebase:firebase-bom:31.2.0')
    implementation 'com.google.firebase:firebase-analytics:17.2.2'
    implementation 'com.google.firebase:firebase-appcheck-debug:16.0.0-beta01'
    implementation 'com.google.android.play:integrity:1.3.0'
}

android\build.gradle #

buildscript {
    ext.kotlin_version = '1.8.0'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.google.gms:google-services:4.3.13'
        classpath 'com.android.tools.build:gradle:7.4.2'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

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

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

解决方案 #

• 统一Application ID与Namespace：
  当前app\build.gradle中defaultConfig的applicationId为com.freschissimo.usersapp，但android块下的namespace是com.example.users_freschissimo_app，两者不一致导致R8混淆时类路径冲突。将两者修改为相同值，比如统一为com.freschissimo.usersapp：

  defaultConfig {
      applicationId "com.freschissimo.usersapp"
      // 保留其他原有配置
  }
  
  android {
      // 保留其他原有配置
      namespace "com.freschissimo.usersapp"
  }
  

• 清理构建缓存：
  执行以下命令清理旧构建文件，避免残留的BuildConfig类干扰：

  flutter clean
  rm -rf android/.gradle android/build
  flutter pub get
  

• 检查flutter_geofire依赖：
  错误来源于flutter_geofire模块的BuildConfig类，若为第三方依赖，尝试更新至最新版本；若为本地模块，确保其namespace与主项目一致。

• 添加R8混淆规则（可选）：
  若统一ID后仍有问题，在app\proguard-rules.pro中添加针对BuildConfig的规则：

  -keep class com.freschissimo.usersapp.BuildConfig { *; }
  

内容的提问来源于stack exchange，提问作者Simone