A shortcut API to validate Android Gradle plugin version validity.

ValidateAndroidPlugin.kt

package com.sample.coolplugin

import org.gradle.api.Plugin
import org.gradle.api.Project

/**
 * Verifies if the plugin supports Android Gradle plugin of version 3.0 or 3.1.
 */
internal fun Plugin<Project>.validateAndroidPluginVersion3or31(errorMessage: String) {
    var gradlePluginVersion: String? = null
    var exception: Exception? = null

    try {
        gradlePluginVersion = Class.forName("com.android.builder.Version")
            .getDeclaredField("ANDROID_GRADLE_PLUGIN_VERSION")
            .get(this)
            .toString()
    } catch (e: Exception) {
        exception = e
    }

    try {
        gradlePluginVersion = Class.forName("com.android.builder.model.Version")
            .getDeclaredField("ANDROID_GRADLE_PLUGIN_VERSION")
            .get(this)
            .toString()
    } catch (e: Exception) {
        exception = e
    }

    if (gradlePluginVersion == null && exception != null) {
        throw IllegalStateException(errorMessage, exception)
    } else if (gradlePluginVersion == null) {
        throw IllegalStateException(errorMessage)
    }
}