SQLiteDatabase null value

Hey I use SQLiteDatabase to store the value of the checkbox weither 1 or 0 and based on the DB value I set or unset the checkbox ,it is working perfectly but the problem occurs when it return null value ?! actually I have a list of events once the user click on that event , the details of that event will be displayed. At the beginning the DB is empty but once the user click or unclick checkbox, theses values will be stored and the last value will be shown next time