java - How to make sure AsyncTask is executed -

i'm pretty new android development, feel have relatively simple question here , have managed tie down more complex parts overlook more simple bits. i've setup imageadapter class handles displaying images gridview in 1 of fragments. following tutorial displayed list of items in array.

i'm using asynctask populate arraylist, , converting arraylist standard array picasso can deal when displaying content.

my problem asynctask section of imageadapter not getting executed, imagearr[] picasso uses remaining empty.

how can make sure asynctask section of adapter executed?

i've tried this, doesn't seem working , think i'm little bit off...

    public void oncreate() {     new getprojects().execute(); } 

i've attached code bellow, appreciated!

note; servicehandler retrieving data @ url , turning string can parsed.

public class imageadapter extends baseadapter {   //json url private static string url = "www.myjsonsourceurl.com";  //json nodes  private static final string tag_logo = "logopath";  arraylist<string> imageurls = new arraylist<string>();  string[] imagearr = imageurls.toarray(new string[imageurls.size()]);   private context mcontext;  public imageadapter(context c) {     mcontext = c; }  public int getcount() {     return imagearr.length; }  public object getitem(int position) {     return null; }  public long getitemid(int position) {     return 0; }   public void oncreate() {     new getprojects().execute(); }   // create new imageview each item referenced adapter public view getview(int position, view convertview, viewgroup parent) {      imageview imageview;     if (convertview == null) {         // if it's not recycled, initialize attributes         imageview = new imageview(mcontext);         imageview.setlayoutparams(new gridview.layoutparams(185, 185));         imageview.setscaletype(imageview.scaletype.center_crop);         imageview.setpadding(3, 3, 3, 3);     } else {         imageview = (imageview) convertview;     }      picasso.with(mcontext).setindicatorsenabled(true);     picasso.with(mcontext).setloggingenabled(true);      picasso.with(mcontext).load(imagearr[position]).placeholder(r.drawable.ajaxloader).error(r.drawable.imageunavailable).into(imageview);     return imageview; }  // references our images //async task json making http call public class getprojects extends asynctask<void, void, void> {      @override     protected void onpreexecute() {         super.onpreexecute();         // nothing right       }      @override     protected void doinbackground(void... arg0) {         // creating service handler class instance         servicehandler sh = new servicehandler();          // making request url , getting response         string jsonstr = sh.makeservicecall(url, servicehandler.get);          log.d("response: ", "> " + jsonstr);          if (jsonstr != null) {             try {                 jsonarray json = new jsonarray(jsonstr);                   // looping through applications                 (int = 0; < json.length(); i++) {                      jsonobject p = json.getjsonobject(i);                      string logopath = p.getstring(tag_logo);                      imageurls.add(logopath);                  }             } catch (jsonexception e) {                 e.printstacktrace();             }         } else {             log.e("servicehandler", "couldn't data url");           }          return null;     }       @override     protected void onpostexecute(void result) {         super.onpostexecute(result);       }   } } 

you need call in activity or fragment list defined not in adapter this. move asynctask class activity , call there.

asynctask gives methods onpreexecute() , onpostexecute() can toast message task started or completed. , should call setadapter() in onpostexecute() of class.