Kactivity.kt

package com.example.nevin.myapplication

import android.app.Activity
import android.app.Application
import android.os.Bundle
import com.jakewharton.threetenabp.AndroidThreeTen
import org.jetbrains.anko.button
import org.jetbrains.anko.centerInParent
import org.jetbrains.anko.onClick
import org.jetbrains.anko.relativeLayout
import org.threeten.bp.Instant


public class MyApp : Application() {

    override fun onCreate() {
        super.onCreate()
        AndroidThreeTen.init(this)

    }

}

public class KActivity : Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        relativeLayout {
            button("Add a Custom View") {
                val info = Instant.now().toString()
                onClick { ViewController.showLogin(this@KActivity, info) }
            }.lparams {
                centerInParent()
            }

        }
    }
}

ViewController.kt

package com.example.nevin.myapplication

import android.app.Activity
import android.content.Context
import android.transition.TransitionManager
import android.widget.EditText
import android.widget.FrameLayout
import android.widget.LinearLayout
import org.jetbrains.anko.*

/**
 * Created by nevin on 11/7/15.
 */

public class ViewController(val context: Context) {

    companion object {

        // interface for you to show this custom view to screen
        // pass info as kind of "bind" data
        public fun showLogin(act: Activity , info: String) {
            val root = act.find<FrameLayout>(android.R.id.content)
            TransitionManager.beginDelayedTransition(root)
            root.addView(genLoginView(act,info))

        }

        // this is where you used to inflate your layout.xml and setup child after onFinishInflate()
        private fun genLoginView(context: Context, info: String ): LinearLayout {

            val layout = context.verticalLayout {
                backgroundColor = 0xffffff.opaque
                textView("View added @$info")
                val name = editText{
                    hint = "Enter your name"

                }
                button("Say Hello") {
                    onClick {
                        name.validateWith(lengthCheck)
                    }
                }

            }
            return layout
        }
    }
}


// function expression
val lengthCheck: (String) -> Boolean = {  it.length > 2 }


// extension function for EditText to validate its' text
fun EditText.validateWith(func: (String) -> Boolean) {
    if (func(this.text.toString())) {
        context.toast("Welcome ${this.text.toString()}!")
    }else{
        context.toast("Name not valid")
    }
}