MainActivity in Java compared to in Kotlin.

MainActivity.java

package com.codeschool.candycoded;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        TextView textView = (TextView)this.findViewById(
                R.id.text_view_title);

        textView.setText("Welcome to Candy Coded!");

        ArrayList<String> candy_list = new ArrayList<String>(
                Arrays.asList("La La Lollipop", "Shooting Stars", "Tart Pop", "Citrus Stick",
                "Sour Drops", "Super Pop", "La La Lollipop", "Shooting Stars",
                "Tart Pop", "Citrus Stick", "Sour Drops", "Super Pop",
                "La La Lollipop", "Shooting Stars", "Tart Pop"));


        ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                this,
                R.layout.list_item_candy,
                R.id.text_view_candy,
                candy_list);

        ListView listView = (ListView)this.findViewById(
                R.id.list_view_candy);

        listView.setAdapter(adapter);

        Context context = this;
        String text = "Hello toast!";
        int duration = Toast.LENGTH_SHORT;

        Toast toast = Toast.makeText(context, text, duration);
        toast.show();

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Toast toast = Toast.makeText(MainActivity.this, ""+i, Toast.LENGTH_SHORT);
                toast.show();
            }
        });

    }
}

MainActivity.kt

package com.codeschool.candykotlin

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.ListView
import android.widget.TextView
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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

        val textView: TextView = this?.findViewById(R.id.text_view_title) as TextView
        textView?.setText(R.string.products_title)

        val candy_list = arrayOf("La La Lollipop", "Shooting Stars", "Tart Pop", "Citrus Stick",
                                 "Sour Drops", "Super Pop", "La La Lollipop", "Shooting Stars",
                                 "Tart Pop", "Citrus Stick", "Sour Drops", "Super Pop",
                                 "La La Lollipop", "Shooting Stars", "Tart Pop")

        val adapter: ArrayAdapter<String> = ArrayAdapter<String>(this, R.layout.list_item_candy,
                                                                 R.id.text_view_candy, candy_list)
        val listView:ListView = this?.findViewById(R.id.list_view_candy) as ListView
        listView?.adapter = adapter

        val context = this
        val text = "Hello toast!"
        val duration = Toast.LENGTH_SHORT

        val toast = Toast.makeText(context, text, duration)
        toast.show()

        listView?.setOnItemClickListener { parent, view, position, id ->
            Toast.makeText(this, position, Toast.LENGTH_SHORT).show()
        }
    }
}