无法为 org.gradle.api.Project 类型的根项目“RoomWordSample”获取未知属性“roomVersion”

Question

I am trying to learn about Android room from https://codelabs.developers.google.com/codelabs/android-room-with-a-view-kotlin/#3

Fourth part is about updating Gradle files. It gives several code snippets to include in

build.gradle (Module: app)

I have included all the implementations, plugins etc mentioned on the page.

   apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

apply plugin: 'kotlin-kapt'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.2"
    defaultConfig {
        applicationId "com.testing.roomwordsample"
        minSdkVersion 18
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    packagingOptions {
        exclude 'META-INF/atomicfu.kotlin_module'
    }
}


dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.core:core-ktx:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'

    // Room components
    implementation "androidx.room:room-runtime:$rootProject.roomVersion"
    kapt "androidx.room:room-compiler:$rootProject.roomVersion"
    implementation "androidx.room:room-ktx:$rootProject.roomVersion"
    androidTestImplementation "androidx.room:room-testing:$rootProject.roomVersion"

// Lifecycle components
    implementation "androidx.lifecycle:lifecycle-extensions:$rootProject.archLifecycleVersion"
    kapt "androidx.lifecycle:lifecycle-compiler:$rootProject.archLifecycleVersion"
    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$rootProject.archLifecycleVersion"

// Kotlin components
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$rootProject.coroutines"
    api "org.jetbrains.kotlinx:kotlinx-coroutines-android:$rootProject.coroutines"

// Material design
    implementation "com.google.android.material:material:$rootProject.materialVersion"

// Testing
    testImplementation 'junit:junit:4.12'
    androidTestImplementation "androidx.arch.core:core-testing:$rootProject.coreTestingVersion"
}

ext {
    roomVersion = '2.2.5'
    archLifecycleVersion = '2.2.0'
    coreTestingVersion = '2.1.0'
    materialVersion = '1.1.0'
    coroutines = '1.3.4'
}

But build has failed and gives this error.

Could not get unknown property 'roomVersion' for root project 'RoomWordSample' of type org.gradle.api.Project.

This is what build window is showing. Error window

Answer 1

Step 5 of the Codelab instructions indicate you should add the ext-block containing the version strings to the Project build.gradle . You added it to the app module build.gradle .

Cut this text from the app module build.gradle and paste it into the project build.gradle :

ext {
    roomVersion = '2.2.5'
    archLifecycleVersion = '2.2.0'
    coreTestingVersion = '2.1.0'
    materialVersion = '1.1.0'
    coroutines = '1.3.4'
}