Я не показывал данные в макете?

Question

Я не показывал данные в макете, но в logcat показывается вывод. Я храню некоторые данные в базе данных реального времени firebase, и это работает, но эти извлеченные данные не могут отображаться в макете.

ShowQuiz Activity:

public class ShowQuizActivity extends AppCompatActivity implements View.OnClickListener {

    final static int INTERVAL = 1000;
    final static int TIMEOUT = 7000;

    int progressValue = 0;

    List<Question> questionList;
    CountDownTimer mCountDownTimer;

    ProgressBar progressBar;
    Button btnA,btnB,btnC,btnD;
    TextView  txtScore,txtQuestionNum,txtQuestion;

    int score = 0,index = 0,thisQuestion = 0,totalQuestion,correctAnswer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_show_quiz);

        questionList = new ArrayList<>();

        progressBar = findViewById(R.id.progressBar);

        txtQuestion = findViewById(R.id.question);
        txtQuestionNum = findViewById(R.id.quNum);
        txtScore = findViewById(R.id.score);

        btnA = findViewById(R.id.option1);
        btnB = findViewById(R.id.option2);
        btnC = findViewById(R.id.option3);
        btnD = findViewById(R.id.option4);

        btnA.setOnClickListener(this);
        btnB.setOnClickListener(this);
        btnC.setOnClickListener(this);
        btnD.setOnClickListener(this);

        DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
        DatabaseReference questionRef = rootRef.child("Question");
        ValueEventListener valueEventListener = new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                //List<Question> questionList = new ArrayList<>();
                for(DataSnapshot ds : dataSnapshot.getChildren()) {
                    Question q = ds.getValue(Question.class);
                    questionList.add(q);
                    String answer = q.getAnswer();
                    String option1 = q.getOption1();
                    String option2 = q.getOption2();
                    String option3 = q.getOption3();
                    String option4 = q.getOption3();
                    String question = q.getQuestion();
                    Log.d("=>", answer + "/" + option1 + "/" + option2 + "/" + option3 + "/" + option4 + "/" + question);
                }

                //Do what you need to do with your list
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Log.d("=>", databaseError.getMessage()); //Don't ignore errors!
            }
        };
        questionRef.addListenerForSingleValueEvent(valueEventListener);
    }

    @Override
    public void onClick(View view) {

        mCountDownTimer.cancel();

        if (index < totalQuestion){
            Button ClickedButton = (Button) view;
            if (ClickedButton.getText().equals(questionList.get(index).getAnswer())){

                score+=10;
                correctAnswer++;
                showQuestion(index++);
            }
            else {
                showQuestion(++index);
            }
            txtScore.setText(String.format("%d",score));
        }

    }

    private void showQuestion(int index) {

        if (index < totalQuestion){
            thisQuestion++;
            txtQuestionNum.setText(String.format("%d/%d",thisQuestion,totalQuestion));
            progressBar.setProgress(0);
            progressValue = 0;

            txtQuestion.setText(questionList.get(index).getQuestion());
            btnA.setText(questionList.get(index).getOption1());
            btnB.setText(questionList.get(index).getOption2());
            btnC.setText(questionList.get(index).getOption3());
            btnD.setText(questionList.get(index).getOption4());

        }
        else {
            Intent intent = new Intent(this,ScoreActivity.class);
            Bundle dataSend = new Bundle();
            dataSend.putInt("SCORE",score);
            dataSend.putInt("TOTAL",totalQuestion);
            dataSend.putInt("CORRECT",correctAnswer);
            intent.putExtras(dataSend);
            startActivity(intent);
            finish();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        totalQuestion = questionList.size();
        mCountDownTimer = new CountDownTimer(TIMEOUT,INTERVAL) {
            @Override
            public void onTick(long l) {
                progressBar.setProgress(progressValue);
                progressValue++;
            }

            @Override
            public void onFinish() {

                mCountDownTimer.cancel();
                showQuestion(++index);
            }
        };
        showQuestion(++index);
    }
}

Question class is here:
public class Question {

    private String answer,option1,option2,option3,option4,question;

    public Question() {

    }

    public Question(String answer, String option1, String option2, String option3, String option4, String question) {
        this.answer = answer;
        this.option1 = option1;
        this.option2 = option2;
        this.option3 = option3;
        this.option4 = option4;
        this.question = question;
    }

    public String getAnswer() {
        return answer;
    }

    public void setAnswer(String answer) {
        this.answer = answer;
    }

    public String getOption1() {
        return option1;
    }

    public void setOption1(String option1) {
        this.option1 = option1;
    }

    public String getOption2() {
        return option2;
    }

    public void setOption2(String option2) {
        this.option2 = option2;
    }

    public String getOption3() {
        return option3;
    }

    public void setOption3(String option3) {
        this.option3 = option3;
    }

    public String getOption4() {
        return option4;
    }

    public void setOption4(String option4) {
        this.option4 = option4;
    }

    public String getQuestion() {
        return question;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

}

Источник выходного изображения Logcat: https://i.pinimg.com/originals/48/d4/5d/48d45de210192fa3922c24151e3b21de.png Что я могу сделать? Пожалуйста, помогите мне. Спасибо