Hi,
I guess Robert is right since my code look like this (inside an
AsyncTask), but the exception appears from time to time, not always but
enought for being annoying.
....
int i=0;
do
{
Plan aux= new Plan((SoapObject)itemsSeccion.getProperty(i));
planes.add(aux);
publishProgress();
i++;
}while(i<5);
......
@Override
protected void onProgressUpdate(Void... values)
{
arrayAdapter.notifyDataSetChanged();
}
...
So, is there any new advice for this?
Regards.
2009/11/20 Romain Guy <[email protected]>
> As soon as you change the count you must notifyDatasetChanged().
>
> On Fri, Nov 20, 2009 at 10:59 PM, Robert Woodruff <[email protected]>
> wrote:
> > Hi Romain,
> >
> >
> >
> > Thanks for the info. I think you are saying that the small example below,
> > all of which runs on the UI thread, will cause the exception to be
> thrown?
> > Right?
> >
> >
> >
> >> 1. Change the count in the base adapter
> >
> >> 2. notifyDataSetChanged() // Which captures a count and will react some
> >> time in the future
> >
> >> 3. Immediately change the count in the base adapter, again
> >
> >
> >
> > Even though the count is only ever changed in the UI thread? It may
> explain
> > why the exception is being thrown in one of my apps by ListView even
> though
> > the adapter count is only ever changed in the UI thread.
> >
> >
> >
> > Say there is a thread running, in an AsyncTask, gathering data to be
> placed
> > in the adapter. It reaches a point to report that data is to be added to
> the
> > Adapter. The AsyncTask.doInBackground() calls publishProgress() which
> > queues a Handler on the UI thread to eventually call onProgressUpdate().
> >
> >
> >
> > Eventually the onProgressUpdate() Handler runs on the UI thread and
> causes
> > the adapter count to change. But notifyDataSetChanged() was called before
> > the publishProgress () Handler runs and the Handler runs before the
> ListView
> > Handler comes around to update the list. So ListView throws an exception
> > because it sees a different count than when notifyDataSetChanged() was
> > called. But the Adapter count was changed always on the UI thread.
> >
> >
> >
> > This brings back the question: When is it safe to change the count in a
> > BaseAdapter()? It seems like there should be a semaphore or listener or
> > something that says "Now it is OK to change the count/Now it is NOT OK to
> > change the count" Or maybe notifyDataSetChanged() could tell the ListView
> it
> > to suspend operations, update the count and continue operations.
> >
> >
> >
> > If I am not too far off base with this it would be good to know when it
> is
> > safe to change the adapter count.
> >
> >
> >
> > Thank you,
> >
> > On Fri, Nov 20, 2009 at 4:14 PM, Romain Guy <[email protected]>
> wrote:
> >>
> >> > 1. Change the count in the base adapter
> >> > 2. notifyDataSetChanged() // Which will react some time in the future
> >> > 3. immediately change the count in the base adapter, again
> >>
> >> > Or another way: when does the ListView grab the BaseAdapter count?
> Does
> >> > it
> >> > grab it on the call to notifyDataSetChanged() or whenever it later
> >> > starts
> >> > the update operation?
> >>
> >> It grabs it in notifyDatasetChanged(). Also, the count change must
> >> happen on the UI thread.
> >>
> >> >
> >> > Thank you,
> >> >
> >> > On Thu, Nov 19, 2009 at 2:24 PM, Dianne Hackborn <[email protected]
> >
> >> > wrote:
> >> >>
> >> >> As the exception says:
> >> >>
> >> >> throw new IllegalStateException("The content of the
> >> >> adapter has changed but "
> >> >> + "ListView did not receive a notification.
> >> >> Make
> >> >> sure the content of "
> >> >> + "your adapter is not modified from a
> >> >> background
> >> >> thread, but only "
> >> >> + "from the UI thread. [in ListView(" +
> getId()
> >> >> +
> >> >> ", " + getClass()
> >> >> + ") with Adapter(" + mAdapter.getClass() +
> >> >> ")]");
> >> >>
> >> >> You can't modify an adapter from a background thread; this must be
> done
> >> >> on
> >> >> the main thread.
> >> >>
> >> >> This exception is not adding a restriction; it is making it more
> >> >> obvious
> >> >> when you do something that would always break in weird, subtle,
> and/or
> >> >> horrible ways.
> >> >>
> >> >> On Thu, Nov 19, 2009 at 5:56 AM, WoodManEXP <[email protected]>
> >> >> wrote:
> >> >>>
> >> >>> For Google about BaseAdapter class
> >> >>>
> >> >>> In Android 1.6 and 2.0 the BaseAdapter class has apparently been
> >> >>> modified to throw an exception when it sees the Adapter.getCount()
> >> >>> method return a number different than what it picked up when
> >> >>> BaseAdapter.notifyDataSetChanged() was called (at least I did not
> >> >>> observe this behavior in pre 1.6).
> >> >>>
> >> >>> So now the question is, when should one call notifyDataSetChanged()
> or
> >> >>> more importantly, when can the count in the Adapter be safely
> changed?
> >> >>>
> >> >>> Consider the case of an app with a background thread delivering data
> >> >>> to a BaseAdapter at a rate faster than the ListView responds to
> >> >>> notifyDataSetChanged(). Because notifyDataSetChanged() is a
> >> >>> synchronous call and the ListView updates are taking place sometime
> in
> >> >>> the indeterminate future on the UI thread, how can an app know when
> it
> >> >>> is safe to change the adapter count?
> >> >>>
> >> >>> If the app changes the count while the ListView is updating itself
> the
> >> >>> exception will be thrown (and there is no way to catch the
> exception).
> >> >>>
> >> >>> Is there a way to know when it is safe to change the count in the
> >> >>> BaseAdapter?
> >> >>>
> >> >>> --
> >> >>> You received this message because you are subscribed to the Google
> >> >>> Groups "Android Developers" group.
> >> >>> To post to this group, send email to
> >> >>> [email protected]
> >> >>> To unsubscribe from this group, send email to
> >> >>> [email protected]<android-developers%[email protected]>
> >> >>> For more options, visit this group at
> >> >>> http://groups.google.com/group/android-developers?hl=en
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> Dianne Hackborn
> >> >> Android framework engineer
> >> >> [email protected]
> >> >>
> >> >> Note: please don't send private questions to me, as I don't have time
> >> >> to
> >> >> provide private support, and so won't reply to such e-mails. All
> such
> >> >> questions should be posted on public forums, where I and others can
> see
> >> >> and
> >> >> answer them.
> >> >>
> >> >> --
> >> >> You received this message because you are subscribed to the Google
> >> >> Groups "Android Developers" group.
> >> >> To post to this group, send email to
> >> >> [email protected]
> >> >> To unsubscribe from this group, send email to
> >> >> [email protected]<android-developers%[email protected]>
> >> >> For more options, visit this group at
> >> >> http://groups.google.com/group/android-developers?hl=en
> >> >
> >> > --
> >> > You received this message because you are subscribed to the Google
> >> > Groups "Android Developers" group.
> >> > To post to this group, send email to
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> >> > To unsubscribe from this group, send email to
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> >>
> >>
> >>
> >> --
> >> Romain Guy
> >> Android framework engineer
> >> [email protected]
> >>
> >> Note: please don't send private questions to me, as I don't have time
> >> to provide private support. All such questions should be posted on
> >> public forums, where I and others can see and answer them
> >>
> >> --
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> >
> > --
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>
>
>
> --
> Romain Guy
> Android framework engineer
> [email protected]
>
> Note: please don't send private questions to me, as I don't have time
> to provide private support. All such questions should be posted on
> public forums, where I and others can see and answer them
>
> --
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>
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