c.getString could not get field

Question

c.getString(i+2) does not work;我錯過了這些代碼的東西？

錯誤：java.lang.IllegalStateException: get field slot from row 0 col 13 failed

...

static String [] lesson_value; 
    String query = "SELECT id, tag, lesson1, lesson2, lesson3, lesson4, lesson5," + 
        " lesson6, lesson7, lesson8, lesson9, lesson10,lesson11 " + 
        "from mytable order by id DESC limit 1"; 
      Cursor c = db.rawQuery(query,null); 
      if (c != null && c.moveToFirst()) { 
        for(int i=0; i<12; i++) { 
       if (c.getString(i+2) != null) { 
        lesson_value[i] = c.getString(i+2); 
} 
} 

Answer 1

我敢肯定，12在for環應該是一個11。有11節課，索引2到12包含在內，因爲你加了兩個，這意味着索引應該在0到10之間。

也可以運行從2到12包容的for循環不增加了兩個：

for (i = 2; i <= 12; i++) 
    justUse (i);