CODEWITHSUNDEEP
androidlistview
aakash
aakash

Reputation: 991

Android ListView scrolling to top

I have a ListView with custom rows. When any of these rows is clicked, the ListView's data is regenerated. I'd like the list to scroll back to the top when this happens.

I initially tried using setSelection(0) in each row's OnClickListener to achieve this but was unsuccessful (I believe because the ListView loses its scroll position when its data is invalidated - so my call to setSelection is undone. I still don't understand how the ListView decides where to scroll to after invalidation, though).

The only working solution I know of was given by Romain Guy here: http://groups.google.com/group/android-developers/browse_thread/thread/127ca57414035301

It involves (View.post)ing the call to _listView.setSelection(0). I found this to perform quite poorly. The newly generated list shows up with its scroll location unchanged and there is a considerable delay before it scrolls back to the top.

Is there any better way to achieve this functionality?

Any help would be much appreciated.

Thanks!

Upvotes: 79

Views: 74858

Answers (8)

Sampath Kumar
Sampath Kumar

Reputation: 4463

This one worked fine when you want to focus the edittext from listview header

listview.setSelectionFromTop(0,0);

If you want to select the particular index view from listview then 

listview.setSelection(index); // o for top

Upvotes: 2

Hafiz Fahad Munir
Hafiz Fahad Munir

Reputation: 527

On some different requirement. If you want to scroll up just like while chatting. 

        mListView.smoothScrollToPosition(mAdapter.getCount());

Upvotes: 2

Dmitry Polomoshnov
Dmitry Polomoshnov

Reputation: 5374

If you need instant scroll just after ListView adapter's data was changed, pay attention that it might not be yet populated. In this case you should post() your setSelection() or setSelectionAfterHeaderView() via Handler so it will be called later in the queue.

listView.Handler.post(new Runnable() {
            @Override
            public void run() {
                listView.setSelectionAfterHeaderView();    
            }
        });

This worked for me.

Upvotes: 5

radhoo
radhoo

Reputation: 2955

I simply use listview.setSelection(0);

Works fine for me.

Upvotes: 42

N20084753
N20084753

Reputation: 2170

I have tried lot but this one worked for me 

list.smoothScrollToPosition(0);

Upvotes: 102

D. B.
D. B.

Reputation: 1436

call listView.setSelectionAfterHeaderView(); to scroll to top

Upvotes: 134

shaobin0604
shaobin0604

Reputation: 1219

as a workaround, you can create a new adapter containing the new regenerated data, then call ListView.setAdapter. after that call ListView.setSelection(n).

btw, the solution provided by commonsware is worked.

Upvotes: 2

CommonsWare
CommonsWare

Reputation: 1007658

Personally, I recommend you find a different UI pattern. It is possible that users will find your current "click, and the list changes in situ" approach intuitive, but I am skeptical.

You could try subclassing ListView and overriding layoutChildren() to chain to the superclass, then call setSelection(0) in the case where that is needed. If the "considerable delay" is due to just the post() call, this should clear it up.

Upvotes: 4

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