skyhigh: thanks for your reply! > > I haven't tried to do a lazy background image load like you are doing, > > but have done some code that uses a holder/wrapper to store the layout > > findViewById which is a nice optimization so that it doesn't have to > > call inflate and findViewById again when each row is displayed. My > > understanding is that when you do this it will allocate enough views > > for each of the rows that are visible on the screen, and then as a row > > scrolls off the screen, it will reuse the already initialized view for > > a new row that is scrolling onto the screen.
As you can see, I have used a view holder pattern too; as was explained in the Google I/O conference by Romain. > > In looking at your code I think you may have a problem because of the > > way that the views for each row get reused when they disappear from > > sight. The same view that was used for a row that just disappeared > > can be reused for a new row that is appearing as the list scrolls. > > Your getView routine is handling this by detecting that the > > convertView is non-null when it has already been filled in when this > > view was used by a previous row. However you don't have any mechanism > > to detect when a view has been reused and is now displaying a > > different row and the URL has changed to a different URL while the > > background AsyncTask was retrieving the image. By the time the > > AsyncTask finishes retrieving the image, the view that it saved the > > reference to, in order to set the image, could have been reused to > > display a different row in the list. If you can add code to check if > > it is still the expected URL prior to setting the image I think it > > might solve your problem. If the URL has changed then skip setting > > the lazy image on that view, and just add the image to your cache. Thanks for pointing this out; I was able to recreate the situation that you've described by inserting a delay in the doInBackground() method of AsyncTask. Result: When I scrolled a few dozen rows and stopped, the icons in the new Frame displayed the older icons first and then the list was refreshed. I could probably work around this by: 1. Tag the view with some unique Id and when setting the image in the AsyncTask, find the View by Tag, and then proceed with setImage(..). 2. I think, I could optimize the implementation further by not loading the image when the list is scrolling; similar to what SlowAdapter does. -- 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] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
