MainActivity.kt

package com.borntodev.trithep.pueanterngijakaira

import android.Manifest
import android.content.Intent
import android.content.pm.PackageManager
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.support.v4.app.ActivityCompat
import android.support.v4.content.ContextCompat
import android.text.TextUtils
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    var MY_PERMISSIONS_REQUEST_READ_CONTACTS = 21

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        TypefaceUtil.overrideFont(this, "SERIF", "fonts/mitr_regular.ttf")
        setContentView(R.layout.activity_main)

        requestPermission()

        btn_question_submit.setOnClickListener {
            var intent = Intent(this,AnswerActivity::class.java)
            var question = et_question.text.toString().trim()

            if(!TextUtils.isEmpty(question)){
                intent.putExtra("question",question)
                startActivity(intent)
                et_question.setText("")
            }

        }
    }

    private fun requestPermission(){
        // Here, thisActivity is the current activity
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {

            // Permission is not granted
            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                // Show an explanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.
            } else {
                // No explanation needed, we can request the permission.
                ActivityCompat.requestPermissions(this,
                    arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE),
                    MY_PERMISSIONS_REQUEST_READ_CONTACTS)

                // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
                // app-defined int constant. The callback method gets the
                // result of the request.
            }
        } else {
            // Permission has already been granted
        }
    }
}