此SQLite查询有什么问题？

Question

I can guarantee that the database has all the columns and values I am looking for.

The query comes back with a CursorOutOfBounds . Does anyone have any ideas why and what I should test?

    Cursor c = db.rawQuery("SELECT * FROM table WHERE _id="+nextvalue+"" , null);
    c.moveToFirst();
    numval = c.getInt(c.getColumnIndex("_id"));                 
    c.close();

Logcat output

11-22 00:08:36.614: ERROR/AndroidRuntime(25405): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0

Answer 1

The query is returning an empty result set. There are no records with the id of nextvalue (whatever that is). You should check that moveToFirst() succeeded:

if (c.moveToFirst()) {
    numval = c.getInt(c.getColumnIndex("_id"));
} else {
    // no results returned
}
c.close();

Answer 2

Does the statement is in bindview of CursorAdapter ? if it is, try to remove c.moveToFirst()