3-5

MainActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    // ここから追加
    countLabel = findViewById(R.id.countLabel);
    questionLabel = findViewById(R.id.questionLabel);
    answerBtn1 = findViewById(R.id.answerBtn1);
    answerBtn2 = findViewById(R.id.answerBtn2);
    answerBtn3 = findViewById(R.id.answerBtn3);
    answerBtn4 = findViewById(R.id.answerBtn4);