Question

第一个问题是Question_oceans，见下面的代码。试图让用户注意到它无法获得＆＃34; Prevoius＆＃34;按下按钮时的问题，因为这是第一个问题＆＃34;我得到一个错误。

private Question[] mQuestionBank = new Question[]{
        new Question(R.string.question_oceans, true),
        new Question(R.string.question_mideast, false),
        new Question(R.string.question_africa, false),
        new Question(R.string.question_americas, true),
        new Question(R.string.question_asia, true),
};

private int mCurrentIndex = 0;

private void updateQuestion() {
    int question = mQuestionBank[mCurrentIndex].getTextResId();
    mQuestionTextView.setText(question);
}

private void lastQuestion(boolean userPressedPrevious) {
    boolean answerIsYes = mQuestionBank[mCurrentIndex].isAnswerTrue();

    int messageQuesId = 0;

    if (userPressedPrevious == answerIsYes) {
        messageQuesId = R.string.not_previous;
    } else {
        updateQuestion();
    }

    Toast.makeText(this, messageQuesId, Toast.LENGTH_SHORT).show();
}

private void checkAnswer(boolean userPressedTrue) {
    boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();

    int messageResId = 0;

    if (userPressedTrue == answerIsTrue) {
        messageResId = R.string.correct_toast;
    } else {
        messageResId = R.string.incorrect_toast;
    }

    Toast.makeText(this, messageResId, Toast.LENGTH_SHORT).show();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_quiz);

    mQuestionTextView = (TextView) findViewById(R.id.question_text_view);

    mTrueButton = (Button) findViewById(R.id.true_button);
    mTrueButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkAnswer(true);
        }

    });

    mFalseButton = (Button) findViewById(R.id.false_button);
    mFalseButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkAnswer(false);
        }
    });

    mPreviousButton = (Button) findViewById(R.id.previous_button);
    mPreviousButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mCurrentIndex = (mCurrentIndex - 1) % mQuestionBank.length;
            updateQuestion();
            lastQuestion(true);
        }
    });
    updateQuestion();

    mNextButton = (Button) findViewById(R.id.next_button);
    mNextButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mCurrentIndex = (mCurrentIndex + 1) % mQuestionBank.length;
            updateQuestion();
        }
    });

    updateQuestion();

Answer 1

也许你应该使用try catch语句。如果再次运行它，您可能会看到一个logcat错误，告诉您它是什么问题。在捕获中，你可以做一个Toast说，＆＃34;抱歉，以前的问题不可用＆＃34;。祝你好运！

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