Android studio / Gradle javadoc task

Maybe you have got the solution to this. Just in case not, below is how I generate API doc for my Jenkins CI.

task generateApiDoc() {
    group "reporting"
    description "Generates Javadoc."
}

android.libraryVariants.all { variant ->
    // Only consider release 
    if (variant.buildType.name == "release") {
        def task = project.tasks.create("generate${variant.name.capitalize()}Javadoc", Javadoc) {
            group "ApiDoc"
            description "Generates Javadoc for $variant.name."

            // Source files from the variant
            source = variant.javaCompiler.source
            // Classpath from the variant + android.jar
            classpath = variant.javaCompiler.classpath + files(prj.android.getBootClasspath()) + files("$buildDir/intermediates/classes/release")

            /* add the excluded packages */
            exclude "**/R**"
            exclude "**/BuildConfig*"

            options.windowTitle = "My Library"
            options.memberLevel = JavadocMemberLevel.PROTECTED
            options.linkSource false
            options.author = true
            //options.links("http://docs.oracle.com/javase/7/docs/api/", "http://d.android.com/reference");

            failOnError false
        }

        task.dependsOn assemble

        generateApiDoc.dependsOn task
    }
}

Then run below gradle commands to get your api doc in place of "$buildDir/docs".

./gradlew assembleRelease
./gradlew generateApiDoc

---

Edit for Gradle Plugin 3.4.1

android.libraryVariants.all { variant ->

    def task = project.tasks.create("generate${variant.name.capitalize()}Javadoc", Javadoc) {
        title "API Documentation (${project.android.defaultConfig.versionName})"
        group "ApiDoc"
        description "Generates Javadoc for $variant.name."

        // Source files from the variant
        source = variant.sourceSets.collect { it.java.sourceFiles }.inject { m, i -> m + i }

        // To fix issue: Error: Can not create variant 'android-lint' after configuration ': library: debugRuntimeElements' has been resolved
        doFirst {
            classpath = project.files(variant.javaCompileProvider.get().classpath.files,
                    project.android.getBootClasspath())
        }

        if (JavaVersion.current().isJava8Compatible()) {
            options.addStringOption('Xdoclint:none', '-quiet')
        }

        exclude "**/R"
        exclude "**/R.**"
        exclude "**/R\$**"
        exclude "**/BuildConfig*"

        if (JavaVersion.current().isJava8Compatible()) {
            options.addStringOption('Xdoclint:none', '-quiet')
        }

        options.windowTitle = "API Documentation (${project.android.defaultConfig.versionName})"
        options.memberLevel = JavadocMemberLevel.PROTECTED
        options.linkSource false
        options.author = false

        failOnError true
    }

    task.dependsOn "assemble${variant.name.capitalize()}"
    generateApiDoc.dependsOn task
}

I use a gradle task that just executes a bash script file, with a single (pretty long) javadoc command.

What you can do is run the Javadoc generation from Android Studio once, then copy the executed javadoc command from the Studio log, with all the right parameters, and automate the execution of the same command in your gradle.