Flutter构建APK报错：Could not find method buildTypes() 求解

问题 #

我想通过Android Studio构建Flutter APK用于手机测试，操作步骤是点击Build > Flutter > Build APK，但构建失败。报错指向app/build.gradle第73行，提示Could not find method buildTypes() for arguments...。我已经确认buildTypes是在android{}代码块内，以下是项目和app模块的build.gradle配置代码，求解决办法。

构建报错日志 #

C:\SRC\flutter\bin\flutter.bat --no-color build apk

 Building with sound null safety 

Running Gradle task 'assembleRelease'...                        

FAILURE: Build failed with an exception.

* Where:
Build file 'C:\Users\Can Ahmet\StudioProjects\myapp\myapp\android\app\build.gradle' line: 73

* What went wrong:
A problem occurred evaluating project ':app'.
> Could not find method buildTypes() for arguments [build_72oyoy28ktxj66hn01bbfxy4$_run_closure5@613623d3] on project ':app' of type org.gradle.api.Project.

* 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 11s
Gradle task assembleRelease failed with exit code 1
Running Gradle task 'assembleRelease'...                           18,0s
Process finished with exit code 1

项目根目录build.gradle #

buildscript {
    ext.kotlin_version = '1.6.21'
    repositories {
        google()
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:7.0.4'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

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


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

task clean(type: Delete) {
    delete rootProject.buildDir
}

app模块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"

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 {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.example.myapp"
        // You can update the following values to match your application needs.
        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
        minSdkVersion flutter.minSdkVersion
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName

    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
}

解决方案 #

问题根源是app模块build.gradle里的语法错误，导致Gradle无法正确解析脚本，进而误报找不到buildTypes()方法。

1. 修复语法错误
   打开app模块的build.gradle文件，找到第10行左右的这段代码：

   localPropertiesFile.withReader('UTF-8') { reader -
       localProperties.load(reader)
   }
   

   把其中的reader -改成reader ->（Groovy闭包的正确语法）：

   localPropertiesFile.withReader('UTF-8') { reader ->
       localProperties.load(reader)
   }
   

2. 重新构建
   保存修改后，重新执行Build APK操作，或在终端运行flutter build apk命令。

如果修复后仍有问题，可尝试：

• 检查local.properties中Flutter SDK路径是否正确，路径避免空格或特殊字符
• 执行flutter clean清理构建缓存后再重新构建
• 确认gradle版本（7.0.4）与当前Flutter版本兼容（建议Flutter 2.8.x及以上）

内容的提问来源于stack exchange，提问作者CanKURT