[Kotlin Quiz ver2] 4-2

MainActivity.kt

    override fun onCreate(savedInstanceState: Bundle?) {
        /* 省略 */

        binding.answerBtn1.setOnClickListener { checkAnswer(it) }
        binding.answerBtn2.setOnClickListener { checkAnswer(it) }
        binding.answerBtn3.setOnClickListener { checkAnswer(it) }
        binding.answerBtn4.setOnClickListener { checkAnswer(it) }

        showNextQuiz()
    }