禁用ListView滚动到顶部

Question

I have a listview to which items are added dynamically to the top of the list. I show some latest events occurring at the top of the list. The problem is, these events occur very frequently, like 5 events in a second. This makes the list go down. Suppose user is looking at one event, then when new event occurs it pushes the event he was reading below, and that disappears. I want the new events to be added at the top but it should be shown only when he scrolls up. I call notifydatasetchanged on the adapter once new events occur and this pushes the list down. Is there anyway I can freeze the scrolling. I tried to disable the scrolling by setTranscriptMode. But it doesn't seem to help. Kindly give me some hints and point me

Answer 1

What you can do is try to get the visible position of ListView on the screen using getFirstVisiblePosition() and then set the Adapter again with setSelection of position you got.

int position = mListView.getFirstVisiblePosition();
mListView.setAdapter(adapter);
mListView.setSelection(position + 1);

I guess you would need (position + 1) because you are adding items on top of the List for every single item added to List.

Answer 2

To show latest events as you require you need to set android:transcriptMode="normal" This will by default set the focus to last item whenever data set is changed.

http://developer.android.com/reference/android/widget/AbsListView.html#attr_android:transcriptMode

Also I you want to freeze scrolling then you can set setOnScrollListener() and update the list only then.