ItemDetailActivity.kt

package com.badoo.myapplication

import android.content.Intent
import android.os.Bundle
import android.support.design.widget.FloatingActionButton
import android.support.v4.app.NavUtils
import android.support.v7.app.AppCompatActivity
import android.support.v7.widget.Toolbar
import android.view.MenuItem
import org.jetbrains.anko.sdk25.coroutines.onClick

/**
 * An activity representing a single Item detail screen. This
 * activity is only used narrow width devices. On tablet-size devices,
 * item details are presented side-by-side with a list of items
 * in a [ItemListActivity].
 */
class ItemDetailActivity : AppCompatActivity() {
    lateinit var fab: FloatingActionButton

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_item_detail)
        val toolbar = findViewById(R.id.detail_toolbar) as Toolbar
        setSupportActionBar(toolbar)

        fab = findViewById(R.id.fab) as FloatingActionButton
//        fab.setOnClickListener { view ->
//            Snackbar.make(view, "Replace with your own detail action", Snackbar.LENGTH_LONG)
//                    .setAction("Action", null).show()
//        }

        // Show the Up button in the action bar.
        val actionBar = supportActionBar
        actionBar?.setDisplayHomeAsUpEnabled(true)

        // savedInstanceState is non-null when there is fragment state
        // saved from previous configurations of this activity
        // (e.g. when rotating the screen from portrait to landscape).
        // In this case, the fragment will automatically be re-added
        // to its container so we don't need to manually add it.
        // For more information, see the Fragments API guide at:
        //
        // http://developer.android.com/guide/components/fragments.html
        //
        if (savedInstanceState == null) {
            // Create the detail fragment and add it to the activity
            // using a fragment transaction.
            val arguments = Bundle()
            arguments.putString(ItemDetailFragment.ARG_ITEM_ID,
                    intent.getStringExtra(ItemDetailFragment.ARG_ITEM_ID))
            val fragment = ItemDetailFragment()
            fragment.arguments = arguments
            supportFragmentManager.beginTransaction()
                    .add(R.id.item_detail_container, fragment)
                    .commit()
        }

        println(tryToCountButtonClicks(fab))
        fab.performClick()
    }

    fun tryToCountButtonClicks(button: FloatingActionButton): Int {
        var clicks = 0
        button.onClick {

            println(++clicks)
        }
      
        return clicks
    }

    override fun onBackPressed() {
//        super.onBackPressed()
        println(tryToCountButtonClicks(fab))
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        val id = item.itemId
        if (id == android.R.id.home) {
            // This ID represents the Home or Up button. In the case of this
            // activity, the Up button is shown. Use NavUtils to allow users
            // to navigate up one level in the application structure. For
            // more details, see the Navigation pattern on Android Design:
            //
            // http://developer.android.com/design/patterns/navigation.html#up-vs-back
            //
            NavUtils.navigateUpTo(this, Intent(this, ItemListActivity::class.java))
            return true
        }
        return super.onOptionsItemSelected(item)
    }


}