public void updateQuestion() {
        String content = library.getQuestions().get(library.getQuestionIndex()).getContent();
        String a = library.getQuestions().get(library.getQuestionIndex()).getAnswerA();
        String b = library.getQuestions().get(library.getQuestionIndex()).getAnswerB();
        String c = library.getQuestions().get(library.getQuestionIndex()).getAnswerC();
        String d = library.getQuestions().get(library.getQuestionIndex()).getAnswerD();
        taQuestion.setText(content);
        btA.setText(a);
        btB.setText(b);
        btC.setText(c);
        btD.setText(d);
    }