如何在android中使用JSON數組在測驗中隨機提問？

Question

我正在開發一個測驗，其中存儲了50個問題，並且希望用戶每次玩游戲時都能在測驗中隨機顯示。我該怎么做？ 是否可以使用json隨機化問題？請幫助我..我非常感謝您的幫助..謝謝。

public class Question1 extends Activity {

Intent menu = null;
BufferedReader bReader = null;
static JSONArray quesList = null;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.question10);

    Thread thread = new Thread() {
        public void run() {
            try {
                Thread.sleep(1 * 1000);
                finish();
                loadQuestions();
                Intent intent = new Intent(Question1.this,
                        Question2.class);
                Question1.this.startActivity(intent);
            } catch (Exception e) {
            }
        }
    };
    thread.start();

}

private void loadQuestions() throws Exception {
    try {
        InputStream questions = this.getBaseContext().getResources()
                .openRawResource(R.raw.questions);
        bReader = new BufferedReader(new InputStreamReader(questions));
        StringBuilder quesString = new StringBuilder();
        String aJsonLine = null;
        while ((aJsonLine = bReader.readLine()) != null) {
            quesString.append(aJsonLine);
        }
        Log.d(this.getClass().toString(), quesString.toString());
        JSONObject quesObj = new JSONObject(quesString.toString());
        quesList = quesObj.getJSONArray("Questions");
        Log.d(this.getClass().getName(),
                "Num Questions " + quesList.length());
    } catch (Exception e) {

    } finally {
        try {
            bReader.close();
        } catch (Exception e) {
            Log.e("", e.getMessage().toString(), e.getCause());
        }

    }

}

public static JSONArray getQuesList(){

    return quesList;



}

}

public class Question2 extends Activity {
/** Called when the activity is first created. */


TextView question, items = null;
RadioButton answer1 = null;
RadioButton answer2 = null;
RadioButton answer3 = null;
RadioGroup answers = null;
int selectedAnswer = -1;
int quesIndex = 0;
int numEvents = 0;
int selected[] = null;
int correctAns[] = null;
boolean review = false;
Button next = null;
int score;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.startquiz);


    try {

        items = (TextView)findViewById(R.id.displayitems);
        question = (TextView) findViewById(R.id.displayquestion);
        answer1 = (RadioButton) findViewById(R.id.option1);
        answer2 = (RadioButton) findViewById(R.id.option2);
        answer3 = (RadioButton) findViewById(R.id.option3);
        answers = (RadioGroup) findViewById(R.id.QueGroup1);


        next = (Button) findViewById(R.id.selected);
        next.setOnClickListener(nextListener);

        selected = new int[Question1.getQuesList().length()];
        java.util.Arrays.fill(selected, -1);
        correctAns = new int[Question1.getQuesList().length()];
        java.util.Arrays.fill(correctAns, -1);

        this.showQuestion(0, review);



    } catch (Exception e) {
        Log.e("", e.getMessage().toString(), e.getCause());
    }

}

private void showQuestion(int qIndex, boolean review) {
    try {
        JSONObject aQues = Question1.getQuesList().getJSONObject(
                qIndex);
        String quesValue = aQues.getString("Question");
        if (correctAns[qIndex] == -1) {
            String correctAnsStr = aQues.getString("CorrectAnswer");
            correctAns[qIndex] = Integer.parseInt(correctAnsStr);
        }

        question.setText(quesValue.toCharArray(), 0, quesValue.length());
        answers.check(-1);
        answer1.setTextColor(Color.BLACK);
        answer2.setTextColor(Color.BLACK);
        answer3.setTextColor(Color.BLACK);
        JSONArray ansList = aQues.getJSONArray("Answers");
        String aAns = ansList.getJSONObject(0).getString("Answer");
        answer1.setText(aAns.toCharArray(), 0, aAns.length());
        aAns = ansList.getJSONObject(1).getString("Answer");
        answer2.setText(aAns.toCharArray(), 0, aAns.length());
        aAns = ansList.getJSONObject(2).getString("Answer");
        answer3.setText(aAns.toCharArray(), 0, aAns.length());
        Log.d("", selected[qIndex] + "");
        if (selected[qIndex] == 0)
            answers.check(R.id.option1);
        if (selected[qIndex] == 1)
            answers.check(R.id.option2);
        if (selected[qIndex] == 2)
            answers.check(R.id.option3);

        setText();
        if (quesIndex == (Question1.getQuesList().length() - 1))
            next.setEnabled(false);

        if (quesIndex < (Question1.getQuesList().length() - 1))
            next.setEnabled(true);

        if (review) {
            Log.d("review", selected[qIndex] + "" + correctAns[qIndex]);
            ;
            if (selected[qIndex] != correctAns[qIndex]) {
                if (selected[qIndex] == 0)
                    answer1.setTextColor(Color.RED);
                if (selected[qIndex] == 1)
                    answer2.setTextColor(Color.RED);
                if (selected[qIndex] == 2)
                    answer3.setTextColor(Color.RED);
            }
            if (correctAns[qIndex] == 0)
                answer1.setTextColor(Color.GREEN);
            if (correctAns[qIndex] == 1)
                answer2.setTextColor(Color.GREEN);
            if (correctAns[qIndex] == 2)
                answer3.setTextColor(Color.GREEN);
        }
    } catch (Exception e) {
        Log.e(this.getClass().toString(), e.getMessage(), e.getCause());
    }
}


private void setAnswer() {
    if (answer1.isChecked())
        selected[quesIndex] = 0;
    if (answer2.isChecked())
        selected[quesIndex] = 1;
    if (answer3.isChecked())
        selected[quesIndex] = 2;



    Log.d("", Arrays.toString(selected));
    Log.d("", Arrays.toString(correctAns));

}

private OnClickListener nextListener = new OnClickListener() {
    public void onClick(View v) {
        setAnswer();

        for(int i=0; i<correctAns.length; i++){

            if ((correctAns[i] != -1) || (correctAns[i] == selected[i]))
            {
                if (correctAns[i] == selected[i])
                score++;
                Toast.makeText(getApplicationContext(), "Your answer is correct!", Toast.LENGTH_SHORT).show();
            }else
        {
            Toast.makeText(getApplicationContext(), "Your answer is wrong...", Toast.LENGTH_SHORT).show();
        }

        quesIndex++;
        if (quesIndex >= Question1.getQuesList().length())
            //quesIndex = Question1.getQuesList().length() - 1;

        showQuestion(quesIndex, review);
        }

    }
};
private void setText() {
    this.setTitle("Question     " + (quesIndex + 1) + "out of     "
            + Question1.getQuesList().length());
    items.setGravity(250);
}

public void reload() {

Intent intent = getIntent();
overridePendingTransition(0, 0);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
finish();

overridePendingTransition(0, 0);
startActivity(intent);
}

}

Answer 1

使用((int) Math.random() * <size of your array>)為問題數組生成隨機索引