Using WHERE Clause SQLite database in Android?

This is my code:

public int getIdMotChuDe(String tenChuDe) {
        int IDChuDe = 0;
        try
        {
            Cursor c = null;
            c = database.rawQuery("SELECT ChuDeID FROM DanhSachChuDe WHERE TenChuDe = ?", new String[] {tenChuDe});
            c.moveToFirst();
            IDChuDe = c.getInt(c.getColumnIndex("ChuDeID"));
            c.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return IDChuDe;
    }

I'm trying to get ChuDeID from DanhSachChuDe table with condition in WHERE clause. But i don't know why this function always return 0. Help me please. Thanks! Sorry because my english.