Database io exception: FileSystemError(12)

[pedjasmek]

I am developing an app that uses multiple screen.The main screen has one button which I use to read some data from the database.If some value is not inserted into one database table,second screen is displayed containing a text field to enter that value and a button for storing it into the database.When this second screen is displayed and the button on that screen is pressed,the value is stored in the database and the main screen is showed again.But when I press the button on the main screen in order to read the data from the database,io exception FileSystemError(12) occurs.Can someone help me with this?

[Chaoss]

check your database connection, is it still closed?

[pedjasmek]

I've checked it and found one place that is entered only once but I didn't place the close() method there.Problem is solved.This is what happens when you have a large code and you use the database a lot
Thanks