Refactor some build logic to the buildSrc & gradle kotlin-dsl

app/build.gradle

@@ -21,14 +21,14 @@ apply plugin: 'kotlin-kapt'
 apply plugin: 'androidx.navigation.safeargs'
 
 android {
-    compileSdkVersion rootProject.compileSdkVersion
+    compileSdkVersion Config.compileSdkVersion
     dataBinding {
         enabled = true
     }
     defaultConfig {
         applicationId "com.google.samples.apps.sunflower"
-        minSdkVersion rootProject.minSdkVersion
-        targetSdkVersion rootProject.targetSdkVersion
+        minSdkVersion Config.minSdkVersion
+        targetSdkVersion Config.targetSdkVersion
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         versionCode 1
         versionName "0.1.6"
@@ -47,28 +47,28 @@ android {
 }
 
 dependencies {
-    kapt "androidx.room:room-compiler:$rootProject.roomVersion"
-    kapt "com.github.bumptech.glide:compiler:$rootProject.glideVersion"
-    implementation "android.arch.navigation:navigation-fragment-ktx:$rootProject.navigationVersion"
-    implementation "android.arch.navigation:navigation-ui-ktx:$rootProject.navigationVersion"
-    implementation "android.arch.work:work-runtime-ktx:$rootProject.workVersion"
-    implementation "androidx.appcompat:appcompat:$rootProject.supportLibraryVersion"
-    implementation "androidx.constraintlayout:constraintlayout:$rootProject.constraintLayoutVersion"
-    implementation "androidx.core:core-ktx:$rootProject.ktxVersion"
-    implementation "androidx.legacy:legacy-support-v4:$rootProject.supportLibraryVersion"
-    implementation "androidx.lifecycle:lifecycle-extensions:$rootProject.lifecycleVersion"
-    implementation "androidx.recyclerview:recyclerview:$rootProject.supportLibraryVersion"
-    implementation "androidx.room:room-runtime:$rootProject.roomVersion"
-    implementation "com.github.bumptech.glide:glide:$rootProject.glideVersion"
-    implementation "com.google.android.material:material:$rootProject.supportLibraryVersion"
-    implementation "com.google.code.gson:gson:$rootProject.gsonVersion"
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$rootProject.kotlinVersion"
+    kapt Libs.room_compiler
+    kapt Libs.com_github_bumptech_glide_compiler
+    implementation Libs.navigation_fragment_ktx
+    implementation Libs.navigation_ui_ktx
+    implementation Libs.work_runtime_ktx
+    implementation Libs.appcompat
+    implementation Libs.constraintlayout
+    implementation Libs.core_ktx
+    implementation Libs.legacy_support_v4
+    implementation Libs.lifecycle_extensions
+    implementation Libs.recyclerview
+    implementation Libs.room_runtime
+    implementation Libs.glide
+    implementation Libs.material
+    implementation Libs.gson
+    implementation Libs.kotlin_stdlib_jdk8
 
     // Testing dependencies
-    androidTestImplementation "androidx.arch.core:core-testing:$rootProject.coreTestingVersion"
-    androidTestImplementation "androidx.test.espresso:espresso-contrib:$rootProject.espressoVersion"
-    androidTestImplementation "androidx.test.espresso:espresso-core:$rootProject.espressoVersion"
-    androidTestImplementation "androidx.test.espresso:espresso-intents:$rootProject.espressoVersion"
-    androidTestImplementation "androidx.test.uiautomator:uiautomator:$rootProject.uiAutomatorVersion"
-    testImplementation "junit:junit:$rootProject.junitVersion"
+    androidTestImplementation Libs.core_testing // room
+    androidTestImplementation Libs.espresso_contrib
+    androidTestImplementation Libs.espresso_core
+    androidTestImplementation Libs.espresso_intents
+    androidTestImplementation Libs.uiautomator
+    testImplementation Libs.junit
 }

build.gradle

@@ -14,33 +14,15 @@
  * limitations under the License.
  */
 
-buildscript {
-    // Define versions in a single place
-    ext {
-        // Sdk and tools
-        compileSdkVersion = 28
-        minSdkVersion = 19
-        targetSdkVersion = 28
+/**
+* Part of the build logic has been moved to the buildSrc directory
+* Versions are defined in buildSrc/src/main/java/Versions.kt
+* Libraries are defined in buildSrc/src/main/java/Libs.kt
+* Other configurations are defined in buildSrc/src/main/java/Config.kt
+*/
 
-        // App dependencies
-        constraintLayoutVersion = '2.0.0-alpha2'
-        coreTestingVersion = '2.0.0'
-        espressoVersion = '3.1.0-alpha4'
-        glideVersion = '4.8.0'
-        gradleVersion = '3.2.0'
-        gsonVersion = '2.8.2'
-        junitVersion = '4.12'
-        kotlinVersion = '1.3.0-rc-146'
-        ktlintVersion = '0.29.0'
-        ktxVersion = '1.0.0'
-        lifecycleVersion = '2.0.0'
-        navigationVersion = '1.0.0-alpha06'
-        roomVersion = '2.0.0'
-        runnerVersion = '1.0.1'
-        supportLibraryVersion = '1.0.0'
-        uiAutomatorVersion = '2.2.0-alpha4'
-        workVersion = '1.0.0-alpha09'
-    }
+
+buildscript {
 
     repositories {
         google()
@@ -49,13 +31,14 @@ buildscript {
     }
 
     dependencies {
-        classpath "com.android.tools.build:gradle:$gradleVersion"
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
-        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:$navigationVersion"
+        classpath "com.android.tools.build:gradle:" + Versions.com_android_tools_build_gradle
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:" + Versions.kotlin_gradle_plugin
+        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:" + Versions.navigation_safe_args_gradle_plugin
     }
 }
 
 plugins {
+    id("jmfayard.github.io.gradle-kotlin-dsl-libs") version "0.2.4" // $ gw syncLibs
     id "com.diffplug.gradle.spotless" version "3.13.0"
 }
 
@@ -70,6 +53,6 @@ allprojects {
 spotless {
     kotlin {
         target "**/*.kt"
-        ktlint(ktlintVersion)
+        ktlint(Config.ktlintVersion)
     }
 }

buildSrc/.gitignore

@@ -0,0 +1,2 @@
+/build
+.gradle/

buildSrc/build.gradle.kts

@@ -0,0 +1,8 @@
+
+plugins {
+    `kotlin-dsl`
+}
+repositories {
+    jcenter()
+}
+

buildSrc/src/main/kotlin/Config.kt

@@ -0,0 +1,9 @@
+object Config {
+    const val compileSdkVersion = 28
+    const val minSdkVersion = 19
+    const val targetSdkVersion = 28
+    const val ktlintVersion = "0.29.0"
+}
+
+const val com_diffplug_gradle_spotless_gradle_plugin: String =
+        "3.13.0" // available milestone: "3.15.0"

buildSrc/src/main/kotlin/Libs.kt

@@ -0,0 +1,163 @@
+import kotlin.String
+
+/**
+ * Generated by [gradle-kotlin-dsl-libs](https://github.com/jmfayard/gradle-kotlin-dsl-libs)
+ *
+ * Run again
+ *   `$ ./gradlew syncLibs`
+ * to update this file */
+object Libs {
+    /**
+     * [aapt2 website](https://developer.android.com/studio) */
+    const val aapt2: String = "com.android.tools.build:aapt2:" + Versions.aapt2
+
+    /**
+     * [appcompat website](http://developer.android.com/tools/extras/support-library.html) */
+    const val appcompat: String = "androidx.appcompat:appcompat:" + Versions.appcompat
+
+    /**
+     * [gradle website](https://developer.android.com/studio) */
+    const val com_android_tools_build_gradle: String =
+            "com.android.tools.build:gradle:" + Versions.com_android_tools_build_gradle
+
+    const val com_diffplug_gradle_spotless_gradle_plugin: String =
+            "com.diffplug.gradle.spotless:com.diffplug.gradle.spotless.gradle.plugin:" + Versions.com_diffplug_gradle_spotless_gradle_plugin
+
+    /**
+     * [compiler website](https://github.com/bumptech/glide) */
+    const val com_github_bumptech_glide_compiler: String =
+            "com.github.bumptech.glide:compiler:" + Versions.com_github_bumptech_glide_compiler
+
+    /**
+     * [constraintlayout website](http://tools.android.com) */
+    const val constraintlayout: String =
+            "androidx.constraintlayout:constraintlayout:" + Versions.constraintlayout
+
+    /**
+     * [core-ktx website](http://developer.android.com/tools/extras/support-library.html) */
+    const val core_ktx: String = "androidx.core:core-ktx:" + Versions.core_ktx
+
+    /**
+     * [core-testing website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val core_testing: String = "androidx.arch.core:core-testing:" + Versions.core_testing
+
+    const val databinding_adapters: String =
+            "androidx.databinding:databinding-adapters:" + Versions.databinding_adapters
+
+    /**
+     * [databinding-common website](https://developer.android.com/studio) */
+    const val databinding_common: String =
+            "androidx.databinding:databinding-common:" + Versions.databinding_common
+
+    /**
+     * [databinding-compiler website](https://developer.android.com/studio) */
+    const val databinding_compiler: String =
+            "androidx.databinding:databinding-compiler:" + Versions.databinding_compiler
+
+    const val databinding_runtime: String =
+            "androidx.databinding:databinding-runtime:" + Versions.databinding_runtime
+
+    /**
+     * [espresso-contrib website](https://developer.android.com/testing) */
+    const val espresso_contrib: String =
+            "androidx.test.espresso:espresso-contrib:" + Versions.espresso_contrib
+
+    /**
+     * [espresso-core website](https://developer.android.com/testing) */
+    const val espresso_core: String =
+            "androidx.test.espresso:espresso-core:" + Versions.espresso_core
+
+    /**
+     * [espresso-intents website](https://developer.android.com/testing) */
+    const val espresso_intents: String =
+            "androidx.test.espresso:espresso-intents:" + Versions.espresso_intents
+
+    /**
+     * [glide website](https://github.com/bumptech/glide) */
+    const val glide: String = "com.github.bumptech.glide:glide:" + Versions.glide
+
+    /**
+     * [gson website](https://github.com/google/gson) */
+    const val gson: String = "com.google.code.gson:gson:" + Versions.gson
+
+    const val jmfayard_github_io_gradle_kotlin_dsl_libs_gradle_plugin: String =
+            "jmfayard.github.io.gradle-kotlin-dsl-libs:jmfayard.github.io.gradle-kotlin-dsl-libs.gradle.plugin:" + Versions.jmfayard_github_io_gradle_kotlin_dsl_libs_gradle_plugin
+
+    /**
+     * [junit website](http://junit.org) */
+    const val junit: String = "junit:junit:" + Versions.junit
+
+    /**
+     * [kotlin-android-extensions website](https://kotlinlang.org/) */
+    const val kotlin_android_extensions: String =
+            "org.jetbrains.kotlin:kotlin-android-extensions:" + Versions.kotlin_android_extensions
+
+    /**
+     * [kotlin-annotation-processing-gradle website](https://kotlinlang.org/) */
+    const val kotlin_annotation_processing_gradle: String =
+            "org.jetbrains.kotlin:kotlin-annotation-processing-gradle:" + Versions.kotlin_annotation_processing_gradle
+
+    /**
+     * [kotlin-gradle-plugin website](https://kotlinlang.org/) */
+    const val kotlin_gradle_plugin: String =
+            "org.jetbrains.kotlin:kotlin-gradle-plugin:" + Versions.kotlin_gradle_plugin
+
+    /**
+     * [kotlin-stdlib-jdk8 website](https://kotlinlang.org/) */
+    const val kotlin_stdlib_jdk8: String =
+            "org.jetbrains.kotlin:kotlin-stdlib-jdk8:" + Versions.kotlin_stdlib_jdk8
+
+    /**
+     * [legacy-support-v4 website](http://developer.android.com/tools/extras/support-library.html) */
+    const val legacy_support_v4: String =
+            "androidx.legacy:legacy-support-v4:" + Versions.legacy_support_v4
+
+    /**
+     * [lifecycle-extensions website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val lifecycle_extensions: String =
+            "androidx.lifecycle:lifecycle-extensions:" + Versions.lifecycle_extensions
+
+    /**
+     * [lint-gradle website](https://developer.android.com/studio) */
+    const val lint_gradle: String = "com.android.tools.lint:lint-gradle:" + Versions.lint_gradle
+
+    /**
+     * [material website](http://developer.android.com/tools/extras/support-library.html) */
+    const val material: String = "com.google.android.material:material:" + Versions.material
+
+    /**
+     * [navigation-fragment-ktx website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val navigation_fragment_ktx: String =
+            "android.arch.navigation:navigation-fragment-ktx:" + Versions.navigation_fragment_ktx
+
+    /**
+     * [navigation-safe-args-gradle-plugin website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val navigation_safe_args_gradle_plugin: String =
+            "android.arch.navigation:navigation-safe-args-gradle-plugin:" + Versions.navigation_safe_args_gradle_plugin
+
+    /**
+     * [navigation-ui-ktx website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val navigation_ui_ktx: String =
+            "android.arch.navigation:navigation-ui-ktx:" + Versions.navigation_ui_ktx
+
+    /**
+     * [recyclerview website](http://developer.android.com/tools/extras/support-library.html) */
+    const val recyclerview: String = "androidx.recyclerview:recyclerview:" + Versions.recyclerview
+
+    /**
+     * [room-compiler website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val room_compiler: String = "androidx.room:room-compiler:" + Versions.room_compiler
+
+    /**
+     * [room-runtime website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val room_runtime: String = "androidx.room:room-runtime:" + Versions.room_runtime
+
+    /**
+     * [uiautomator website](https://developer.android.com/testing) */
+    const val uiautomator: String = "androidx.test.uiautomator:uiautomator:" + Versions.uiautomator
+
+    /**
+     * [work-runtime-ktx website](https://developer.android.com/topic/libraries/architecture/index.html) */
+    const val work_runtime_ktx: String =
+            "android.arch.work:work-runtime-ktx:" + Versions.work_runtime_ktx
+}