Question

I’ve read several related posts and even posted and answer here but it seems like I was not able to solve the problem.

I have 3 Activities:
Act1 (main)
Act2
Act3

When going back and forth Act1->Act2 and Act2->Act1 I get no issues
When going Act2->Act3 I get no issues
When going Act3->Act2 I get occasional crashes with the following error: java.lang.IllegalStateException: trying to requery an already closed cursor android.database.sqlite.SQLiteCursor@.... This is a ListView cursor.

What I tried:
1. Adding stopManagingCursor(currentCursor);to the onPause() of Act2 so I stop managing the cursor when leaving Act2 to Act3

protected void onPause() 
{
    Log.i(getClass().getName() + ".onPause", "Hi!");

    super.onPause();
    saveState();

    //Make sure you get rid of the cursor when leaving to another Activity
    //Prevents: ...Unable to resume activity... trying to requery an already closed cursor
    Cursor currentCursor = ((SimpleCursorAdapter)getListAdapter()).getCursor();
    stopManagingCursor(currentCursor);
}

2. When returning back from Act3 to Act2 I do the following:

   private void populateCompetitorsListView()
   {
   ListAdapter currentListAdapter = getListAdapter();
   Cursor currentCursor = null;
   Cursor tournamentStocksCursor = null;

   if(currentListAdapter != null)
   {
   currentCursor = ((SimpleCursorAdapter)currentListAdapter).getCursor();
   
   if(currentCursor != null)
   {
       //might be redundant, not sure
                   stopManagingCursor(currentCursor);
   
       // Get all of the stocks from the database and create the item list
       tournamentStocksCursor = mDbHelper.retrieveTrounamentStocks(mTournamentRowId);
               ((SimpleCursorAdapter)currentListAdapter).changeCursor(tournamentStocksCursor);
       }   
       else
       {
           tournamentStocksCursor = mDbHelper.retrieveTrounamentStocks(mTournamentRowId);
       }
   }
   else
   {
       tournamentStocksCursor = mDbHelper.retrieveTrounamentStocks(mTournamentRowId);
   }
   
       startManagingCursor(tournamentStocksCursor);        
   
       //Create an array to specify the fields we want to display in the list (only name)
       String[] from = new String[] {StournamentConstants.TblStocks.COLUMN_NAME, StournamentConstants.TblTournamentsStocks.COLUMN_SCORE};
   
       // and an array of the fields we want to bind those fields to (in this case just name)
       int[] to = new int[]{R.id.competitor_name, R.id.competitor_score};
   
       // Now create an array adapter and set it to display using our row
       SimpleCursorAdapter tournamentStocks = new SimpleCursorAdapter(this, R.layout.competitor_row, tournamentStocksCursor, from, to);
   
       //tournamentStocks.convertToString(tournamentStocksCursor);
       setListAdapter(tournamentStocks);       
   }
   

So I make sure I invalidate the cursor and use a different one. I found out that when I go Act3->Act2 the system will sometimes use the same cursor for the List View and sometimes it will have a different one.

This is hard to debug and I was never able to catch a crashing system while debugging. I suspect this has to do with the time it takes to debug (long) and the time it takes to run the app (much shorter, no pause due to breakpoints).

In Act2 I use the following Intent and expect no result:

protected void onListItemClick(ListView l, View v, int position, long id) 
{       
    super.onListItemClick(l, v, position, id);

    Intent intent = new Intent(this, ActivityCompetitorDetails.class);

    intent.putExtra(StournamentConstants.App.competitorId, id);
    intent.putExtra(StournamentConstants.App.tournamentId, mTournamentRowId);   

    startActivity(intent);
}

Moving Act1->Act2 Act2->Act1 never gives me trouble. There I use startActivityForResult(intent, ACTIVITY_EDIT); and I am not sure – could this be the source of my trouble?

I would be grateful if anyone could shed some light on this subject. I am interested in learning some more about this subject.

Thanks,D.

Answer 1

I call this a 2 dimensional problem: two things were responsible for this crash:
1. I used startManagingCursor(mItemCursor); where I shouldn’t have.
2. I forgot to initCursorAdapter() (for autocomplete) on onResume()

//@SuppressWarnings("deprecation")
private void initCursorAdapter()
{
    mItemCursor = mDbHelper.getCompetitorsCursor("");      
    startManagingCursor(mItemCursor); //<= this is bad!

    mCursorAdapter = new CompetitorAdapter(getApplicationContext(), mItemCursor);       

    initItemFilter();
}

Now it seems to work fine. I hope so…