A shortcut API to list Android Gradle variants.

ListVariantsAndroidPlugin.kt

/**
 * Returns the collection of Android variants on the basis of applied plugin. If the Android plugins are missing we
 * are throwing build error.
 */
internal fun Project.getAndroidVariantsOrThrow(errorMessage: String): DomainObjectCollection<out BaseVariant> {
    return when {
        this.plugins.hasPlugin("com.android.application") -> {
            val ext = project.extensions.findByType(AppExtension::class.java)
            ext!!.applicationVariants
        }

        this.plugins.hasPlugin("com.android.test") -> {
            val ext = project.extensions.findByType(TestExtension::class.java)
            ext!!.applicationVariants
        }

        this.plugins.hasPlugin("com.android.library") -> {
            val ext = project.extensions.findByType(LibraryExtension::class.java)
            ext!!.libraryVariants
        }

        else -> throw IllegalArgumentException(errorMessage)
    }
}