listview - Android: Where is the correct place to make a http request in a List Adapter -

i have list adapter listview in 1 activity,

now want populate list view data obtain web service. correct place execute async request server obtain json data populate adapter?

1: before instantiate adapter , passing through constructor? dont know how refreshing work.

2: in adapter?

2.1: in adapters constructor?

2.2 in view?

here adapter far:

public class mydevicesadapter extends baseadapter {  private context mcontext; private string tag = "mydevicesadapter";  // keep objects in array private arraylist<mydevice> devices;  /**  * constructor creating devices list adapter  *   * @param context  *            context of calling class  */ public mydevicesadapter(context context) {     mcontext = context;     devices = new arraylist<mydevice>(); }  @override public int getcount() {     return devices.size(); }  @override public object getitem(int position) {     return devices.get(position); }  @override public long getitemid(int position) {     // todo auto-generated method stub     return 0; }  /**  * checks if list empty  */ public boolean isempty() {     return devices.isempty(); }  @override public view getview(final int position, view convertview, viewgroup parent) {      viewholder holder = null;     layoutinflater minflater = (layoutinflater) mcontext             .getsystemservice(activity.layout_inflater_service);      if (convertview == null) {         convertview = minflater.inflate(r.layout.my_device_item, null);         holder = new viewholder();          holder.imageview = (imageview) convertview                 .findviewbyid(r.id.my_device_item_imageview);         holder.txtname = (textview) convertview                 .findviewbyid(r.id.my_device_item_textview_name);          convertview.settag(holder);     } else {         holder = (viewholder) convertview.gettag();     }      // temp variable store current list item     final mydevice deviceitem = (mydevice) getitem(position);      //set image      //set name       //on click listener view     convertview.setonclicklistener(new onclicklistener() {         @override         public void onclick(view v) {         //log.d(tag, "deleting order in position : " + position);         //deleteorder(orders.get(position), position, v);         }     });      return null; }  /**  * private view holder class keeps reference view  * components. used increase performance of listview  */ private class viewholder {     imageview imageview;     textview txtname; } } 

here async request that's going fetch data:

network.login("mydevices",null, new asynchttpresponsehandler() {          @override         public void onsuccess(int statuscode, header[] headers,                 byte[] responsebody) {                   }             @override         public void onfailure(int statuscode, header[] headers,                 byte[] responsebody, throwable error) {             // response failed :(         }     }); 

somewhere else ;)

based on app can trigger download position. should work in seperat thread or using asynctask. not block ui. if data available notify listeners calling notifydatasetchanged() , done. ui been reloaded automatically after call.