android - Not understanding whether to use notifyDataSetChanged() when elements in listview are updated? -

i have android application uses listview adapter of custom objects.

oncreate of activity if list of objects available populate adapter previous objects , make async call fetch new objects , populate adapter.

while populating adapter again old list of elements removed , new added. have not used notifydatasetchanged().

private customadapter listadapter; private gridview gridview;              // oncreateview of fragment if find old list in singleton populate list , shows on screen               function oncreateview()             {              ...             ...              listadapter = new customadapter(getactivity(),                     countersingleton.getinstance(getactivity())                             .getobjects());             gridview.setadapter(listadapter);              ....             ...             new asnyctask().execute();             }               class asnyctask             {                  // fetch new list , replace old list shown                  list<objects> newlist = fetchnewlist();                 listadapter = new customadapter(                                         getactivity(), newlist);                 gridview.setadapter(listadapter);              } 

few questions here:

1. do need use notifydatasetchanged() in asnyctask class after populate adapter creating new instance of it.

2. will old list removed , replaced new list per above code.

do need use notifydatasetchanged() in asnyctask class after populate adapter creating new instance of it.

no need call notifydatasetchanged() because calling setadapter method listview new data-source

will old list removed , replaced new list per above code.

yes listview populate new data.

note: instead of calling setadapter method again-2 showing new data. create method inside adapter update current adapter new data.like:

public void addnewitems(list<objects> itemlist){    1. clear data current adapter     example if using arraylist       arraylist_object.clearall();   2. add itemlist  in arraylist_object      arraylist_object.addall(itemlist);    3. call this.notifydatasetchanged() } 

now call addnewitems update current apdater data asnyctask using same object created first time when listview populated :

listadapter.addnewitems(newlist)