Android Gradle Build Logic

Centralise build configuration in reusable Convention Plugins inside a build-logic/ composite build, so each module's build.gradle.kts collapses to plugins { alias(libs.plugins.myapp.android.library) } plus a namespace.

The canonical worked example is nowinandroid's build-logic/ — start from it rather than hand-rolling. This skill covers the wiring detail that is easy to get wrong, plus the AGP 9 deltas.

The wiring gotcha

build-logic does NOT inherit the root version catalog — recreate it. A composite build has its own settings.gradle.kts; the root libs catalog is invisible inside build-logic until you declare it. Without this the convention plugins can't reference libs.* and fail to compile with Unresolved reference: libs:

// build-logic/settings.gradle.kts
dependencyResolutionManagement {
    versionCatalogs {
        create("libs") { from(files("../gradle/libs.versions.toml")) }
    }
}