CursorWrapper有0行

Question

我在使用自定义CursorWrapper从我的SQLitedatabase获取＆＃34; question＆＃34;对象时遇到问题。我使用一个查询函数返回CursorWrapper，其中所有行都有问题，这些行具有给定的章节索引，并且学习的整数是0.必须存在我在查询函数中找不到的语法错误，因为QuestionCursor来自于此函数有0行，数据库中有三个符合条件的问题。如果你能发现错误会很棒。

我的SQLiteAssetHelper中的查询函数，它返回一个有0行的QuestionsCursor：

public QuestionCursor queryUnlearnedQuestions(int chapterId) {
    Cursor wrapped = getReadableDatabase().query
            (TABLE_QUESTIONS,
            null,
            COLUMN_QUESTIONS_CHAPTER_ID + " = ? AND " + COLUMN_QUESTIONS_LEARNED + " = ? ",
            new String[] {String.valueOf(chapterId), String.valueOf(0)},
            null,
            null,
            COLUMN_QUESTIONS_QUESTION_ID + " asc");
    return new QuestionCursor(wrapped);
}

自定义CursorWrapper

public static class QuestionCursor extends CursorWrapper {
    public QuestionCursor(Cursor cursor) {
        super(cursor);
        // TODO Auto-generated constructor stub
    }

    public Question getQuestion(){
        if(isBeforeFirst()||isAfterLast()) return null;

        Question question = new Question();

        question.setQuestionId(getInt(getColumnIndex(COLUMN_QUESTIONS_QUESTION_ID)));
        question.setCategoryId(getInt(getColumnIndex(COLUMN_QUESTIONS_CHAPTER_ID)));
        question.setDescription(getString(getColumnIndex(COLUMN_QUESTIONS_DESCRIPTION)));
        question.setQuestionText(getString(getColumnIndex(COLUMN_QUESTIONS_QUESTION_TEXT)));
        question.setAnswerText(getString(getColumnIndex(COLUMN_QUESTIONS_ANSWER_TEXT)));
        question.setIsLearned((getInt(getColumnIndex(COLUMN_QUESTIONS_LEARNED)) == 1) ? true:false);
        question.setCorrectAnswers(getInt(getColumnIndex(COLUMN_QUESTIONS_CORRECT_ANSWERS)));
        question.setFalseAnswers(getInt(getColumnIndex(COLUMN_QUESTIONS_FALSE_ANSWERS)));
        question.setLastAnswerDate(new Date(getLong(getColumnIndex(COLUMN_QUESTIONS_LAST_ANSWER_DATE))));

        return question;
    }
}

Singleton调用该函数并将对象放入具有固定长度的ArrayList中。

public ArrayList<Question> getUnlearnedQuestions(int chapterId, int maxlength) {    
    ArrayList<Question> unlearnedQuestions = new ArrayList<Question>();     
    QuestionCursor cursor = mHelper.queryUnlearnedQuestions(chapterId);         

    Log.d(TAG, ""+cursor.getCount()); // returns 0

    for(cursor.moveToFirst(); cursor.getPosition() < maxlength; cursor.moveToNext()){           
            if(!cursor.isAfterLast()){
                unlearnedQuestions.add(cursor.getQuestion());   
            }else{
                break;
            }
    }
    cursor.close();
    return unlearnedQuestions;  
}

整个LearnMode活动，尚未完成。

public class LearnModeActivity extends FragmentActivity {

public static String    EXTRA_CHAPTER_ID = "LearnFragment.chapter_id";  
private static String   TAG              = "LearnModeActivity";     
private static int      LEARN_ARRAY_LENGTH = 7;

private int                 mChapterId;             
private ArrayList<Question> mQuestionList;

private ViewPager           mViewPager;

protected void onCreate(Bundle args) {
    // TODO Auto-generated method stub
    super.onCreate(args);
    mViewPager = new ViewPager(this);
    mViewPager.setId(R.id.view_pager);
    setContentView(mViewPager);

    mQuestionList = ChapterManager.get(this).getUnlearnedQuestions(mChapterId, LEARN_ARRAY_LENGTH);

    Log.d(TAG, "Question List size: "+ mQuestionList.size()); //returns 0

    FragmentManager fm = getSupportFragmentManager();
    mViewPager.setAdapter(new FragmentStatePagerAdapter(fm) {

        @Override
        public int getCount() {
                    //should return mQuestionList.size(); Changed it to three, otherwise getCount is 0 and I get a blank screen and there is no IndexOutOfBondException
            return 3;


        }

        @Override
        public Fragment getItem(int pos) {
            //Indexoutofboundsexception right here
            Question question = mQuestionList.get(pos); 


            return LearnModeFragment.newInstance(question.getQuestionId());
        }
    });

    mViewPager.setOnPageChangeListener(new OnPageChangeListener() {

        @Override
        public void onPageSelected(int index) {
            Question question = mQuestionList.get(index);
            setTitle(question.getQuestionId()+". "+question.getDescription());
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
            // TODO Auto-generated method stub              
        }
    });
}

}

提前致谢