Challenge: Preventing Repeat Answers: How to best save which question has been answered

Android Programming (3rd Edition) 3. The Activity Lifecycle
24

For me
In Question class
private int mAlreadyAnswer = 0;

public int getAlreadyAnswer() {
    return mAlreadyAnswer;
}

public void setAlreadyAnswer(int alreadyAnswer) {
    mAlreadyAnswer = alreadyAnswer;
}

and in MainActivity

private void checkAnswer(boolean userPressedTrue){
    boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();
    int answer = mQuestionBank[mCurrentIndex].getAlreadyAnswer();
    int messageResId = 0;

        if (userPressedTrue == answerIsTrue & answer == 0) {
            messageResId = R.string.correct_toast;
            mQuestionBank[mCurrentIndex].setAlreadyAnswer(1);


        } else if (userPressedTrue != answerIsTrue & answer == 0) {
            messageResId = R.string.incorrect_toast;
            mQuestionBank[mCurrentIndex].setAlreadyAnswer(1);

        } else {
            messageResId = R.string.alreadyAnswer;
        }

        Toast toast1 = Toast.makeText(this, messageResId, Toast.LENGTH_SHORT);
        toast1.setGravity(Gravity.TOP, 0, 0);
        toast1.show();
}

in @String
<string name=“alreadyAnswer”>You are already answer this question</string>