Test of ViewPager

ExampleFragmentPagerAdapter.kt

package com.example.ashia.pagertest

import android.support.v4.app.Fragment
import android.support.v4.app.FragmentManager
import android.support.v4.app.FragmentPagerAdapter

class ExampleFragmentPagerAdapter(fm: FragmentManager?) : FragmentPagerAdapter(fm) {
    override fun getItem(position: Int): Fragment {
        when(position){
            0 -> {
                return TextFragment.newInstance("Good Morning!");
            }
            1 -> {
                return TextFragment.newInstance("Good Evening!");
            }
        }
        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }

    override fun getCount(): Int {
        return 2;
        //TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }

}

MainActivity.kt

package com.example.ashia.pagertest

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.support.v4.view.ViewPager

class MainActivity : AppCompatActivity() {

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

        val vp = findViewById<ViewPager>(R.id.vpMain);
        val efpa = ExampleFragmentPagerAdapter(supportFragmentManager);
        vp.adapter = efpa;

    }
}

TextFragment.kt

package com.example.ashia.pagertest

import android.content.Context
import android.net.Uri
import android.os.Bundle
import android.support.v4.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView


// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"

/**
 * A simple [Fragment] subclass.
 * Activities that contain this fragment must implement the
 * [TextFragment.OnFragmentInteractionListener] interface
 * to handle interaction events.
 * Use the [TextFragment.newInstance] factory method to
 * create an instance of this fragment.
 *
 */
class TextFragment : Fragment() {
    // TODO: Rename and change types of parameters
    private var param1: String? = null
    private var listener: OnFragmentInteractionListener? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        arguments?.let {
            param1 = it.getString(ARG_PARAM1)
        }
    }

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment

        // Followed this: https://qiita.com/Yuki_Yamada/items/6d8b38effeb38ed96d78
        val view = inflater.inflate(R.layout.fragment_text, container, false);

        val text = view.findViewById<TextView>(R.id.txtMain);
        text.text = param1;

        return view;
    }

    // TODO: Rename method, update argument and hook method into UI event
    fun onButtonPressed(uri: Uri) {
        listener?.onFragmentInteraction(uri)
    }

    override fun onAttach(context: Context) {
        super.onAttach(context)
//        if (context is OnFragmentInteractionListener) {
//            listener = context
//        } else {
//            throw RuntimeException(context.toString() + " must implement OnFragmentInteractionListener")
//        }
    }

    override fun onDetach() {
        super.onDetach()
        listener = null
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     *
     *
     * See the Android Training lesson [Communicating with Other Fragments]
     * (http://developer.android.com/training/basics/fragments/communicating.html)
     * for more information.
     */
    interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        fun onFragmentInteraction(uri: Uri)
    }

    companion object {
        /**
         * Use this factory method to create a new instance of
         * this fragment using the provided parameters.
         *
         * @param param1 Parameter 1.
         * @return A new instance of fragment TextFragment.
         */
        // TODO: Rename and change types and number of parameters
        @JvmStatic
        fun newInstance(param1: String) =
                TextFragment().apply {
                    arguments = Bundle().apply {
                        putString(ARG_PARAM1, param1)
                    }
                }
    }
}