DialogSimpleActivity.kt

package com.a2050.rehman.abdul.dialogtest

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.support.v7.app.AlertDialog
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
import android.content.DialogInterface
import android.R.array



class DialogSimpleActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val builder = AlertDialog.Builder(this,R.style.Base_Theme_AppCompat_Dialog_Alert)
        builder.setTitle("Hello Dialog")
        builder.setPositiveButton("OK",null)
        builder.setMessage("This is hello message")
        builder.setNegativeButton("Cancel",null)
        builder.setNeutralButton("Maybe",null)

        btn1.setOnClickListener {
            Toast.makeText(applicationContext,"btn1 Clicked",Toast.LENGTH_LONG).show()
            builder.show()
        }

        btn2.setOnClickListener{
            showDialog()
        }


    }


    fun showDialog() {
        val builder = AlertDialog.Builder(this@MainActivity)
        builder.setTitle("Select Font")

        //list of items
        val items = resources.getStringArray(R.array.Font_Names)
        builder.setSingleChoiceItems(items, 0
        ) { dialog, which ->
            // item selected logic
        }

        val positiveText = getString(android.R.string.ok)
        builder.setPositiveButton(positiveText,
                object:DialogInterface.OnClickListener {
                    override fun onClick(dialog:DialogInterface, which:Int) {
                        // positive button logic
                    }
                })

        val negativeText = getString(android.R.string.cancel)
        builder.setNegativeButton(negativeText,
                object:DialogInterface.OnClickListener {
                    override fun onClick(dialog:DialogInterface, which:Int) {
                        // negative button logic
                    }
                })

        val dialog = builder.create()
        // display dialog
        dialog.show()
    }



}