Flutter集成Firebase报错：app/build.gradle中No signature of method异常

核心问题分析 #

报错提示No signature of method: ...android()，结合你的app/build.gradle代码，存在两处关键错误：

1. 插件应用顺序错误 #

com.google.gms.google-services插件的加载顺序不符合Gradle与Firebase的集成规范，它必须在Android应用插件之后加载，且需放在所有插件的最后位置。

2. MultiDex配置语法错误 #

defaultConfig中的MultiDexEnable true拼写错误，Gradle要求的正确语法是小驼峰格式的multiDexEnabled true。

修正后的完整app/build.gradle代码 #

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'
}

// 调整插件顺序：先Android应用插件，再kotlin插件，再flutter gradle脚本，最后google-services插件
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'

android {
    compileSdkVersion 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.getx.app.db.firebaseApp"
        minSdkVersion flutter.minSdkVersion
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        // 修正MultiDex配置的拼写错误
        multiDexEnabled true
    }

    buildTypes {
        release {
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support:multidex:1.0.3'
}

后续验证步骤 #

• 执行flutter clean清除旧构建缓存
• 重新运行flutter run启动项目

内容的提问来源于stack exchange，提问作者lousea