java - 从 SQLite 数据库生成随机输出

Question

您好，我目前有一个数据库，其中存储了 5 个问题和答案。我想在应用程序每次运行时随机输出三个问题。我有以下代码，但我的应用程序在加载时崩溃

public List<Question> getAllQuestions() {
        List<Question> quesList = new ArrayList<Question>();
        int nQuestions = 3; //select COUNT(*) from questions

        Random random = new Random();
        int id = random.nextInt(nQuestions);

        String selectQuery = "SELECT  id FROM " + TABLE_QUEST;
        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.setQUESTION(cursor.getString(1));
                quest.setANSWER(cursor.getString(2));
                quest.setOPTA(cursor.getString(3));
                quest.setOPTB(cursor.getString(4));
                quest.setOPTC(cursor.getString(5));
                quesList.add(quest);
            } while (cursor.moveToNext());{
                 id = random.nextInt(nQuestions);
            }
        }
        // return quest list
        return quesList;
    }

Answer 1

抱歉，我写这个作为答案，但我没有对问题发表评论的权限，所以我想告诉你，首先，你将永远成为前 3 个随机添加的问题之一问题，因为对于您用作限制的随机 id 3 id = random.nextInt(nQuestions); 而不是 nQuestions (对您来说是 3，您应该使用 questList.size()并对从0到questList.size()的数字执行3次