javadoc.gradle

// build a jar with source files
task sourcesJar(type: Jar) {
    from android.sourceSets.main.java.srcDirs
    classifier = 'sources'
}

task javadoc(type: Javadoc) {
    failOnError  false
    source = android.sourceSets.main.java.sourceFiles
    classpath += project.files(android.getBootClasspath().join(File.pathSeparator))
}

// build a jar with javadoc
task javadocJar(type: Jar, dependsOn: javadoc) {
    classifier = 'javadoc'
    from javadoc.destinationDir
}

artifacts {
    archives sourcesJar
    archives javadocJar
}

android.libraryVariants.all { variant ->
    def name = variant.buildType.name
    def task = project.tasks.create "jar${name.capitalize()}", Jar
    task.dependsOn variant.javaCompile
    task.from variant.javaCompile.destinationDir
    artifacts.add('archives', task);
}