Android library artifact tasks

gistfile1.gradle

if (project.android.hasProperty('libraryVariants')) {
    android.libraryVariants.all { variant ->
        Task javadocTask = task("generate${variant.name.capitalize()}Javadoc", type: Javadoc) {
            group = 'artifact'
            description "Generates Javadoc for $variant.name"

            // Source files from the variant
            source = variant.javaCompiler.source

            // Classpath from the variant + android.jar
            String androidJar = "${android.sdkDirectory}/platforms/${android.compileSdkVersion}/android.jar"
            classpath = variant.javaCompiler.classpath + files(androidJar)

            // The Android online reference doesn't include package-list, so we have to use the local one
            String packageListRef = "${android.sdkDirectory}/docs/reference/"
            options.linksOffline 'http://d.android.com/reference/', packageListRef

            // Additional links for any RxJava references
            options.links 'http://reactivex.io/RxJava/javadoc/'

            // Exclude generated files
            exclude '**/BuildConfig.java'
            exclude '**/R.java'

            // Output to a unique javadoc folder per variant
            destinationDir = new File(project.docsDir, "javadoc-$variant.name")
        }

        task("generate${variant.name.capitalize()}JavadocJar", type: Jar, dependsOn: javadocTask) {
            group = 'artifact'
            description = "Generates Javadoc jar for $variant.name"

            classifier = "$variant.name-javadoc"
            from javadocTask.destinationDir
        }

        task("generate${variant.name.capitalize()}SourcesJar", type: Jar) {
              group = 'artifact'
              description = "Generates sources jar for $variant.name"

              classifier = "$variant.name-sources"
              from variant.javaCompiler.source
        }
    }
}