Kotlin : Start crash

// Application package
package com.madijason.quizzer

// Import all resources
import android.app.Dialog
import android.content.DialogInterface
import android.content.SharedPreferences
import android.icu.text.CaseMap
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.EditText
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
import kotlin.random.Random

// Beginning of the MainActivity class
class MainActivity : AppCompatActivity() {

    // This function is called at the creation of the activity
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        Toast.makeText(applicationContext, "Welcome on Quizzer !", Toast.LENGTH_SHORT).show()
        setLevel()
        checkAnswer()
    }

    // Variables declared
    private val questions = arrayOf<String>("Who is Steve Job ?", "What is Kotlin ?", "What is WHO ?")
    private val firstQuestionAnswer = arrayOf<String>("The creator of Apple", "The creator of Microsoft", "A random guy", "A serial killer")
    private val secondQuestionAnswer = arrayOf<String>("A company", "The best hacker", "The creator of Microsoft", "A thief")
    private val thirdQuestionAnswer = arrayOf<String>("World Humanity Organisation", "A word", "World Health Organisation", "World Heart Ocean")
    private var currentQuestion = 0
    private var userPoint = 0
    private var first_done = false

    // This function is called in the "onCreate" for setup the questions
    private fun setLevel() {
        // Take a random number
        val randomNumber = (1..3).random()
        // Check the random number and setup the question
        if (randomNumber == 1) {
            currentQuestion = 1
            question.text = questions[1]
            first_answer.text = firstQuestionAnswer[1]
            second_answer.text = firstQuestionAnswer[2]
            third_answer.text = firstQuestionAnswer[3]
            fourth_answer.text = firstQuestionAnswer[4]
        } else if (randomNumber == 2) {
            currentQuestion = 2
            question.text = questions[2]
            first_answer.text = secondQuestionAnswer[1]
            second_answer.text = secondQuestionAnswer[2]
            third_answer.text = secondQuestionAnswer[3]
            fourth_answer.text = secondQuestionAnswer[4]
        } else if (randomNumber == 3) {
            currentQuestion = 3
            question.text = questions[3]
            first_answer.text = thirdQuestionAnswer[1]
            second_answer.text = thirdQuestionAnswer[2]
            third_answer.text = thirdQuestionAnswer[3]
            fourth_answer.text = thirdQuestionAnswer[4]
        }
    }

    // This function is called in the "onCreate" for setup the questions
    // Check answer and change level
    private fun checkAnswer() {
        first_answer.setOnClickListener {
            if (currentQuestion == 1) {
                userPoint += 1
                Toast.makeText(applicationContext, "Bravo, you win one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                // Next level
                currentQuestion = 2
                question.text = questions[2]
                first_answer.text = secondQuestionAnswer[1]
                second_answer.text = secondQuestionAnswer[2]
                third_answer.text = secondQuestionAnswer[3]
                fourth_answer.text = secondQuestionAnswer[4]
                first_done = true
            } else if (currentQuestion == 2) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 3
                question.text = questions[3]
                first_answer.text = thirdQuestionAnswer[1]
                second_answer.text = thirdQuestionAnswer[2]
                third_answer.text = thirdQuestionAnswer[3]
                fourth_answer.text = thirdQuestionAnswer[4]
            } else if (currentQuestion == 3) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                if (first_done == false)
                    question.text = questions[1]
                    first_answer.text = firstQuestionAnswer[1]
                    second_answer.text = firstQuestionAnswer[2]
                    third_answer.text = firstQuestionAnswer[3]
                    fourth_answer.text = firstQuestionAnswer[4]
            }
        }
        second_answer.setOnClickListener {
            if (currentQuestion == 1) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 2
                question.text = questions[2]
                first_answer.text = secondQuestionAnswer[1]
                second_answer.text = secondQuestionAnswer[2]
                third_answer.text = secondQuestionAnswer[3]
                fourth_answer.text = secondQuestionAnswer[4]
            } else if (currentQuestion == 2) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 3
                question.text = questions[3]
                first_answer.text = thirdQuestionAnswer[1]
                second_answer.text = thirdQuestionAnswer[2]
                third_answer.text = thirdQuestionAnswer[3]
                fourth_answer.text = thirdQuestionAnswer[4]
            } else if (currentQuestion == 3) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                if (first_done == false)
                    question.text = questions[1]
                    first_answer.text = firstQuestionAnswer[1]
                    second_answer.text = firstQuestionAnswer[2]
                    third_answer.text = firstQuestionAnswer[3]
                    fourth_answer.text = firstQuestionAnswer[4]
            }
        }
        third_answer.setOnClickListener {
            if (currentQuestion == 2) {
                userPoint += 1
                Toast.makeText(applicationContext, "Bravo, you win one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 3
                question.text = questions[3]
                first_answer.text = thirdQuestionAnswer[1]
                second_answer.text = thirdQuestionAnswer[2]
                third_answer.text = thirdQuestionAnswer[3]
                fourth_answer.text = thirdQuestionAnswer[4]
            } else if (currentQuestion == 1) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 2
                question.text = questions[2]
                first_answer.text = secondQuestionAnswer[1]
                second_answer.text = secondQuestionAnswer[2]
                third_answer.text = secondQuestionAnswer[3]
                fourth_answer.text = secondQuestionAnswer[4]
            } else if (currentQuestion == 3) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                if (first_done == false)
                    question.text = questions[1]
                    first_answer.text = firstQuestionAnswer[1]
                    second_answer.text = firstQuestionAnswer[2]
                    third_answer.text = firstQuestionAnswer[3]
                    fourth_answer.text = firstQuestionAnswer[4]
            }
        }
        fourth_answer.setOnClickListener {
            if (currentQuestion == 1) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 2
                question.text = questions[2]
                first_answer.text = secondQuestionAnswer[1]
                second_answer.text = secondQuestionAnswer[2]
                third_answer.text = secondQuestionAnswer[3]
                fourth_answer.text = secondQuestionAnswer[4]
            } else if (currentQuestion == 2) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                currentQuestion = 3
                question.text = questions[3]
                first_answer.text = thirdQuestionAnswer[1]
                second_answer.text = thirdQuestionAnswer[2]
                third_answer.text = thirdQuestionAnswer[3]
                fourth_answer.text = thirdQuestionAnswer[4]
            } else if (currentQuestion == 3) {
                userPoint -= 1
                Toast.makeText(applicationContext, "Wrong, you lose one coin", Toast.LENGTH_SHORT).show()
                Toast.makeText(applicationContext, "Now, you have : ${userPoint.toString()}", Toast.LENGTH_SHORT).show()
                if (first_done == false)
                    question.text = questions[1]
                    first_answer.text = firstQuestionAnswer[1]
                    second_answer.text = firstQuestionAnswer[2]
                    third_answer.text = firstQuestionAnswer[3]
                    fourth_answer.text = firstQuestionAnswer[4]
            }
        }
    }
}