如何在循环中使用游标？ [复制]

Question

问题是我无法加载我的图像，也许我在这里遇到了问题。也许这段代码会出错“java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0”抱歉，我无法描述我的问题 T_T。我是安卓新手。

quest.setImage(Utility.getPhoto(cursor.getBlob(1))); //也许我得到了 这里有问题

DbHelper.java

public List<Question> getAllQuestions(){
            List<Question> quesList = new ArrayList<Question>();
            String selectQuery = "SELECT * FROM " + TABLE_QUEST + " ORDER BY RANDOM() LIMIT 5";
            dbase=this.getReadableDatabase();
            Cursor cursor = dbase.rawQuery(selectQuery, null);
            // looping through all rows and adding to list
            //==============================================
            if (cursor.moveToFirst()) {
                do {
                    Question quest = new Question();

                    quest.setID(cursor.getInt(0));
                    quest.setImage(Utility.getPhoto(cursor.getBlob(1)));
                    quest.setQUESTION(cursor.getString(2));
                    quest.setANSWER(cursor.getString(3));
                    quest.setOPTA(cursor.getString(4));
                    quest.setOPTB(cursor.getString(5));
                    quest.setOPTC(cursor.getString(6));
                    quesList.add(quest);
                } while (cursor.moveToNext());
            }
            // return quest list
            return quesList;
        }

问题.java

    public Bitmap getBitmap(){
     return bmp;
}
    public void setImage(Bitmap img){
    bmp = img;
}

实用程序.java

public class Utility {
    // convert from bitmap to byte array
    public static byte[] getBytes(Bitmap bitmap) {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        bitmap.compress(CompressFormat.PNG, 0, stream);
        return stream.toByteArray();
    }

    // convert from byte array to bitmap
    public static Bitmap getPhoto(byte[] image) {
        return BitmapFactory.decodeByteArray(image, 0, image.length);
    }
}

Answer 1

您的查询似乎没有返回您期望的所有 7 列。

列出查询中的所有实际列名（始终是一个好习惯），这样它会更快地失败并提供更具描述性的消息。

String selectQuery = "SELECT fielName1, fieldName2, "
    + " ..., lastFieldName FROM " + TABLE_QUEST + " ORDER BY RANDOM() LIMIT 5";