Android SQLite SQLiteOpenHelper IllegalStateException - DB Already Closed Error

Question

This has been driving me crazy for a few days now. I have an android application that is pretty complex. It uses multiple threads to pull data from a server and populate t

Answer 1

I had also the same problem 'db already closed exception with a cursor invalid statement in fillWindow() and IllegalStatementException'. What I did was I put my cursor (w/c also comes from SimpleCursorAdapter) to an instance variable instead of a method variable then on my onStop and onPause methods I call stopManagingCursor then on my onResume and onStart methods I call startManagingCursor.

It solved my problem for me and I didn't find any error or warning messages in my logcat after that :) Hope this helps anyone also.

Answer 2

use CursorAdapter.changeCursor(null) ,Can slow the emergence of this bug,But can not completely solve the problom ,Unknown period of time will appear again. This has been driving me crazy too!

Answer 3

Since this question has gotten a good deal of attention, I wanted to answer it and describe what I've learned and what worked for me to correct this problem in my large, database-driven application:

1. Do NOT use managed cursors. There's a reason why they're deprecated. They're completely problematic. Realistically, there's very few scenarios where you actually need to use a managed cursor anyway. Instead, run your query and populate an object with the results. If you're querying for multiple row, create an ArrayList<> of your object to hold all the rows. What I do now is create a function that runs the query and passes me back my ArrayList<> rather than a cursor in the return. I close the cursor within the function and I'm done. For a ListViews, you'll no longer be able to use a SimpleCursorAdapter. Just convert all of these to a BaseAdapter and use your ArrayList<> object to populate it.

2. DO NOT FORGET TO CLOSE ALL YOUR CURSORS. This can also wreak havoc on your app's db connections. I thought I was doing this but, sure enough, found a spot that I wasn't explicitly closing a cursor. So, go through your app and double check all of them.

I'm also using a singleton DatabaseHelper object. I declare a static DatabaseHelper object within my SQLiteOpenHelper class so that I'm getting the same instance every time.

I now have a stable running app that no longer gets these DB errors. I hope this information is helpful to some of you.