A nice post describing that is here http://lucasr.org/2012/04/05/performance-tips-for-androids-listview/ With an example of what is called a view holder to have a performance improvement. Also in the Google IO 2010 it is well explain from the developer itself http://www.youtube.com/watch?v=wDBM6wVEO70
On Sat, Jul 28, 2012 at 2:41 PM, bob <[email protected]> wrote: > Interesting… I usually just create a new View every time in getView… so > I've never run into that. > > > > On Saturday, July 28, 2012 6:10:50 AM UTC-5, Sergio Panico wrote: >> >> Hi all, >> I thank all for your answers. >> >> I've understood the "strange" behaviour that doesn't makes my ListView to >> refreshes correctly. >> >> Here is the link where I've found the solution: >> https://groups.google.com/**forum/?fromgroups#!topic/** >> android-developers/2Ub4yhyKumM<https://groups.google.com/forum/?fromgroups#!topic/android-developers/2Ub4yhyKumM> >> >> This topic clearly explains that, when the callback method "getView" is >> called, the parameter "convertView" is null only when ListView tries to >> draw the first 5 items, from "A" to "E". When I scroll down the content of >> the list, and the ListView draws the items 6 and 7, it "reuses" the views >> previoulsy created, hence "convertView" is not null and my getView >> implementation goes into "else" branch. >> >> What I've missed was to bind the "old" view, with the "new" model item >> getting showed. So the fix was simply to add, in this branch, the update of >> the bind between "recycled" view and model item. >> >> HTH >> Sergio >> >> >> >> Il giorno giovedì 26 luglio 2012 12:59:05 UTC+2, Sergio Panico ha scritto: >>> >>> Hi all, >>> I need your help to understand the refresh behaviour of a ListView where >>> I've defined a my custom view for the ListView's items. >>> >>> I think It's better explain it with an example: >>> my adapter contains 7 items: A, B, C, D, E, F, G correctly initialized, >>> filled and working. The associated ListView shows 5 (out of 7) items: A, B, >>> C, D, E. >>> The problem is that, when I scroll down the ListView's content instead >>> of showing me items F and G, I've got A and B items again. I understood >>> that this is "only" a viewing issue becouse the model elements associated >>> with the last two items, correctly belong to F and G items. :| >>> >>> Following the ovveride of getView(...) method of my adapter (extending >>> BaseAdapter): >>> >>> @Override >>> public View getView(int position, View convertView, ViewGroup >>> parent) { >>> MyItemView miv = (( MyItemView ) convertView); >>> >>> if (context == null) return null; >>> >>> if (convertView == null) { >>> miv = new MyItemView (........); >>> ..... >>> } else { >>> miv.refreshView(); //refresh the view content >>> } >>> >>> return miv; >>> } >>> >>> and the refreshView() method of MyItemView (extending LinearLayout): >>> >>> @Override >>> public void refreshView() { >>> label1.setText(......); >>> label2.setText(......); >>> label2.setText(......); >>> >>> invalidate(); >>> } >>> >>> Thanks a lot to all! >>> Bye >>> Sergio >>> >> -- > 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 > -- 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
