当尝试在Android模拟器上调试我的Flutter应用程序时，我收到以下错误：

Gradle build failed to produce an .apk file. It's likely that this file was generated under <project_folder>\app\build, but the tool couldn't find it.

我一直在StackOverflow和GitHub中爬行以找到根本原因，但找不到任何有效的东西。
我在许多帖子中看到，这种行为可能是由于运行调试时未指定的应用程序风格造成的，但我根本没有定义任何风格。
我试图创建一个全新的项目，并将我的代码粘贴回lib文件夹，但没有任何变化。
命令flutter build appbundle也失败了，所以当我想生成一个应用程序包时，我必须通过Android Studio来完成（我使用VS代码进行编码）。
唯一的方法，我可以让这个应用程序工作在调试模式是切换回flutter version 1.9.1+hotfix.6，这是相当烦人的，因为我有另一个应用程序，工作正常，我必须使用最新版本开发。
这是我的app/build.gradle文件：

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"

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

android {
    compileSdkVersion 28

    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.app"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        resConfigs "es"
    }

    signingConfigs {
       release {
           keyAlias keystoreProperties['keyAlias']
           keyPassword keystoreProperties['keyPassword']
           storeFile file(keystoreProperties['storeFile'])
           storePassword keystoreProperties['storePassword']
       }
   }

    buildTypes {
        release {
           signingConfig signingConfigs.release
           minifyEnabled true
           shrinkResources true
           useProguard true

           proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
       }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.facebook.android:facebook-login:5.15.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
}

apply plugin: 'com.google.gms.google-services'

这是我的gradle-wrapper.properties文件以防万一

#Fri Jun 23 08:50:38 CEST 2017
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip