Android Gradle Build Logic & Convention Plugins

This skill helps you configure a scalable, maintainable build system for Android apps using Gradle Convention Plugins and Version Catalogs, following the "Now in Android" (NiA) architecture.

Goal

Stop copy-pasting code between build.gradle.kts files. Centralize build logic (Compose setup, Kotlin options, Hilt, etc.) in reusable plugins.

Project Structure

Ensure your project has a build-logic directory included in settings.gradle.kts as a composite build.

root/ ├── build-logic/ │ ├── convention/ │ │ ├── src/main/kotlin/ │ │ │ └── AndroidApplicationConventionPlugin.kt │ │ └── build.gradle.kts │ ├── build.gradle.kts │ └── settings.gradle.kts ├── gradle/ │ └── libs.versions.toml ├── app/ │ └── build.gradle.kts └── settings.gradle.kts

Step 1: Configure settings.gradle.kts

Include the build-logic as a plugin management source.

// settings.gradle.kts pluginManagement { includeBuild("build-logic") repositories { google() mavenCentral() gradlePluginPortal() } } dependencyResolutionManagement { repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS) repositories { google() mavenCentral() } }

Step 2: Define Dependencies in libs.versions.toml

Use the Version Catalog for both libraries and plugins.

[versions] androidGradlePlugin = "8.2.0" kotlin = "1.9.20"

[libraries]

...

[plugins] android-application = { id = "com.android.application", version.ref = "androidGradlePlugin" } android-library = { id = "com.android.library", version.ref = "androidGradlePlugin" } kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }

Define your own plugins here

nowinandroid-android-application = { id = "nowinandroid.android.application", version = "unspecified" }

Step 3: Create a Convention Plugin

Inside build-logic/convention/src/main/kotlin/AndroidApplicationConventionPlugin.kt :

import com.android.build.api.dsl.ApplicationExtension import org.gradle.api.Plugin import org.gradle.api.Project import org.gradle.kotlin.dsl.configure

class AndroidApplicationConventionPlugin : Plugin<Project> { override fun apply(target: Project) { with(target) { with(pluginManager) { apply("com.android.application") apply("org.jetbrains.kotlin.android") }

        extensions.configure<ApplicationExtension> {
            defaultConfig.targetSdk = 34
            // Configure common options here
        }
    }
}

}

Don't forget to register it in build-logic/convention/build.gradle.kts :

gradlePlugin { plugins { register("androidApplication") { id = "nowinandroid.android.application" implementationClass = "AndroidApplicationConventionPlugin" } } }

Usage

Apply your custom plugin in your modules (e.g., app/build.gradle.kts ):

plugins { alias(libs.plugins.nowinandroid.android.application) }

This drastically cleans up module-level build files.