Gradle Kotlin-DSL Sample

How to use Kotlin in Gradle? How to use Kotlin in Gradle? Step by step Kotlin-DSL migration guide.

Step by Step Migration Guide to Kotlin-DSL

Step 0:

Create buildSrc directory in root of your project.

Step 1:

Create src/main/java directory in buildSrc

Step 2:

Create your build.gradle.kts file which contains Kotlin-DSL plugin.

import org.gradle.kotlin.dsl.`kotlin-dsl`

plugins {
    `kotlin-dsl`
}

repositories {
    jcenter()
}

Step 3:

Create your dependency and config files in buildSrc/src/main/java

ClassPaths:

object ClassPaths {
    val gradleClasspath = "com.android.tools.build:gradle:${Versions.gradleVersion}"
    val kotlinGradlePluginClasspath = "org.jetbrains.kotlin:kotlin-gradle-plugin:${Versions.kotlinVersion}"
}

Config:

object Config {
    val applicatiınId = "com.raqun.phonebox"
    val testInstrumentationRunner = "android.support.test.runner.AndroidJUnitRunner"
}

Dependencies.kt:

object CoreLibraries {
    val kotlin = "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${Versions.kotlinVersion}"
}

object SupportLibraries {
    val appCompat = "com.android.support:appcompat-v7:${Versions.appCompatVersion}"
}

object TestLibraries {
    val jUnit = "junit:junit:${Versions.jUnitVersion}"
    val runnner = "com.android.support.test:runner:${Versions.testRunnerVersion}"
    val espressoCore = "com.android.support.test.espresso:espresso-core:${Versions.espressoCoreVersion}"
}

Modules:

object Modules {
    val app = ":app"
}

Plugins.kt:

object Plugins {
    val androidApplication = "com.android.application"
    val kotlinAndroid = "kotlin-android"
    val kotlinAndroidExtensions = "kotlin-android-extensions"
}

Versions.kt:

object Release {
    val versionCode = 1
    val versionName = "1.0.0"
}

object Versions {

    /**
     * Sdk Versions
     */
    val compileSdkVersion = 28
    val minSdkVersion = 17
    val targetSdkVersion = 28

    /**
     * Dependency Versions
     */
    const val gradleVersion = "3.2.1"
    const val kotlinVersion = "1.3.11"
    const val appCompatVersion = "28.0.0"
    const val jUnitVersion = "4.12"
    const val testRunnerVersion = "1.0.2"
    const val espressoCoreVersion = "3.0.2"
}

Step 4:

Rename your settings.gradle to settings.gradle.kts
Change include ':app' to include(Modules.app)

Step 5:

Rename your project level build.gradle to build.gradle.kts Refactor your code like the following:

buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath (ClassPaths.gradleClasspath)
        classpath (ClassPaths.kotlinGradlePluginClasspath)

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

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

task<Delete>("clean") {
    delete(rootProject.buildDir)
}

Step 6:

Rename your module level build.gradle to build.gradle.kts Refactor your code like the following:

plugins {
    id(Plugins.androidApplication)
    id(Plugins.kotlinAndroid)
    id(Plugins.kotlinAndroidExtensions)
}

android {
    compileSdkVersion(Versions.compileSdkVersion)
    defaultConfig {
        applicationId = Config.applicatiınId
        minSdkVersion(Versions.minSdkVersion)
        targetSdkVersion(Versions.targetSdkVersion)
        versionCode = Release.versionCode
        versionName = Release.versionName
        testInstrumentationRunner = Config.testInstrumentationRunner
    }
    buildTypes {
        getByName("release") {
            isMinifyEnabled = false
            proguardFiles(getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro")
        }
    }
}

dependencies {
    // Core Libraries
    implementation(CoreLibraries.kotlin)

    // Support Libraries
    implementation(SupportLibraries.appCompat)

    // Testing
    testImplementation(TestLibraries.jUnit)
    androidTestImplementation(TestLibraries.runnner)
    androidTestImplementation(TestLibraries.espressoCore)
}

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