Question

我正在尝试进行多重答案测验。我关注了这个网站： Simple Quiz Game

在Multiple Activity中，我添加了这个：

    QuestionsDbHelper db = new QuestionsDbHelper(this);
    questionsList = db.getAllQuestions();
    currentQuestion=questionsList.get(questionId);

正如你在最后一行所看到的，我得到了这个错误。在QuestionsDbHelper中，我添加了问题，但仍然无法在Activity上显示它们。我已经描述了Manifest文件中的Activity。我从Debug中可以理解的是我的Array是空的，但是我已经插入了问题列表。

有什么想法吗？

Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
            at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251)
            at java.util.ArrayList.get(ArrayList.java:304)
            at com.game.mlm.q2game.MultipleMode.onCreate(MultipleMode.java:36)

我发布的代码没有onCreate和onUpgrade，因为它们非常基本。这是我的QuestionsDbhelper代码：

public void addQuestions(Questions question){
    Log.d("add Questions" , question.toString());

 //   SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_QUESTION, question.getQuestion());
    values.put(KEY_ANSWER, question.getAnswer());
    values.put(KEY_FBUTTON, question.getFirstButton());
    values.put(KEY_SBUTTON, question.getSecondButton());
    values.put(KEY_THBUTTON, question.getThirdButton());

    dbase.insert(TABLE_QUESTIONS, null, values);


}
public List<Questions> getAllQuestions(){
    List<Questions> questionsList = new ArrayList<Questions>();
   //SELECT ALL FROM QUERY
    String selectQuery = "SELECT * FROM " + TABLE_QUESTIONS;
    dbase= this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    //LOOPING THROUGH ALL ROWS AND ADDING TO LIST
    if (cursor.moveToFirst()) {
        do {
            Questions question = new Questions();
            question.setId(cursor.getInt(0));
            question.setQuestion(cursor.getString(1));
            question.setAnswer(cursor.getString(2));
            question.setFirstButton(cursor.getString(3));
            question.setSecondButton(cursor.getString(4));
            question.setThirdButton(cursor.getString(5));
            questionsList.add(question);
        }
        while (cursor.moveToNext());
    }
    Log.d( "getAllQuestions()", questionsList.toString() );
    return questionsList;
}
public int rowcount() {
    int row = 0;
    String selectQuery = "SELECT * FROM " + TABLE_QUESTIONS;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    row = cursor.getCount();
    //  cursor.close();
    return row;
}

Answer 1

您是否检查过问题是否正确？您可能没有使用的问题ID的数据

Answer 2

首先检查数据库中的rowCount返回值。如果是，则使用

将光标移动到第一个位置

 cursor.moveToFirst();

Answer 3

使用getAllQuestions()中的QuestionsDbHelper class方法中的这一行。

String Query = "select * from <table name>";
db = openDataBase();
Cursor cursor = db.rawQuery(Query, null);
// Log.d(LOG_TAG, "Cursor Length: " + cursor.getCount());
while (cursor.moveToNext()) {
<Get all data from table>
}

从SQLite Android获取问题

3 个答案: