Question

我需要提出问题，列：活动，课程和屏幕等于例如：“1”，“2”，“3”。注意：问题也是一栏。

我的代码应该返回一个字符串=“4”但正在返回：

android.database.sqlite.SQLiteCursor@547e1a74

代码：

databaseHelper = Database.getInstance(getApplicationContext());

long id4 = databaseHelper4.insertData("1", "2", "3","4", "5", "6", "7", "8");
String question = databaseHelper4.getQuestion("1", "2", "2");
Message.message(IntroActivity.this, question);

数据库：

public String getQuestion(String activity, String lesson, String screen){

    SQLiteDatabase db = helper.getWritableDatabase();
    String[] columns = {DatabaseHelper.QUESTION};
    Cursor cursor = db.query(DatabaseHelper.TABLE_NAME, columns, DatabaseHelper.ACTIVITY +
    "=?" + " AND " + DatabaseHelper.LESSON + "=?" + " AND " + DatabaseHelper.SCREEN +
    "=?", new String[]{activity, lesson, screen}, null, null, null, null);

    return cursor.toString();

}

Answer 1

下面：

return cursor.toString();

Cursor.toString()方法返回Cursor的字符串表示，而不是Cursor包含的值。

从游标获取QUESTION列值：

cursor.moveToFirst();
String question = cursor.getString(cursor.getColumnIndex(
                                               DatabaseHelper.QUESTION));

Answer 2

而不是返回cursor.toString()，您应该返回

cursor.getString(cursor.getColumnIndex(DatabaseHelper.QUESTION));

致电cursor.moveToFirst();

后

public String getQuestion(String activity, String lesson, String screen){

   SQLiteDatabase db = helper.getWritableDatabase();
   String[] columns = {DatabaseHelper.QUESTION};
   Cursor cursor = db.query(DatabaseHelper.TABLE_NAME, columns, DatabaseHelper.ACTIVITY +
   "=?" + " AND " + DatabaseHelper.LESSON + "=?" + " AND " + DatabaseHelper.SCREEN +
   "=?", new String[]{activity, lesson, screen}, null, null, null, null);

     cursor.moveToFirst()
     return cursor.getString(cursor.getColumnIndex(DatabaseHelper.QUESTION));;

}

如何使用带有WHERE子句的query（）？

2 个答案: