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什么是indexoutofboundsexception？我该怎么修[重复]（1个答案）
18天前关门了。
我使用dbhelper类和以下方法

public List<List<String>> getReservations (String username) {
        List<List<String>> reservations = new ArrayList<List<String>>();
        List<String> row = new ArrayList();
        SQLiteDatabase database = this.getReadableDatabase();
        Cursor c1 = database.rawQuery("SELECT * FROM Reservations WHERE username LIKE '" + username + "'", null);
        while(c1.moveToNext()) {
            row.add(c1.getString(1)); //parkingname
            row.add(c1.getString(2)); //date
            row.add(c1.getString(3)); //time
            reservations.add(row);
            row.clear();
        }
        c1.close();
        return reservations;
    }

我的数据库已填充（100%确定，其他方法有效） db.execSQL("CREATE TABLE Reservations(username VARCHAR, parkingname VARCHAR, date VARCHAR, timeslot VARCHAR);"); 现在每当我尝试

List<List<String>> values = database.getReservations(username);
        text = (TextView) findViewById(R.id.myreservations);
        if(!values.isEmpty()) {
            String b = String.valueOf(values.size());
            List<String> lista = values.get(0); //crashes here
            String a = lista.get(0);
            text.setText(b + a);
        }

应用程序崩溃

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myparking/com.example.myparking.MyReservations}: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0