如何在Android中使用json数组限制问题的显示

Question

hey guys im developing a quiz where i have 50 questions randomly stored using json array, now my problem is all those 50 questions are displayed everytime the user will play.is it possible to limit them if iwant only 10 questions to display?...i have 50 questions stored because it is randomly selected but i want only 10 to display..please help me guys..thanks so much!

public class Question1<JsonObject> extends Activity {



Intent menu = null;
BufferedReader bReader = null;
static JSONArray quesList = null;
static int index = 50;



/** 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 {



        List<JSONObject> question = new ArrayList<JSONObject>();
         int n = Math.min(10, quesList.length());
         for(int i = 0; i < n; i++) {
             JSONObject questions1 = quesList.getJSONObject(i);
             question.add(questions1);


        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()throws JSONException{

      Random rnd = new Random();

        for (int i = quesList.length() - 1; i >= 0; i--)
        {
          int j = rnd.nextInt(i + 1);
          // Simple swap
          Object object = quesList.get(j);
          quesList.put(j, quesList.get(i));
          quesList.put(i, object);
        }
        return quesList;


}

Answer 1

Try to put it this way:

List<JSONObject> question = null;

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());
     }

    question = new ArrayList<JSONObject>();
     int n = Math.min(10, quesList.length());
     for(int i = 0; i < n; i++) {
         JSONObject questions1 = quesList.getJSONObject(i);
         question.add(questions1);

} catch (Exception e) {

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

}

}

Looks like naming in Your program is messed up. There's no specific code, but I assume that You need to use List<JSONObject> question instead of quesList .