android - OnClick() on buttons not working after I do something and return back to button's activity -

i have debugged , found flow of control never reaches onclick() method in main activity after come activity launched main activity.

suspecting gotta 'paused' or 'resumed' state.

in other words, main activity a. , activity launched b. so, launch , work on b. , when return (using hardware button 'back') onclick function doesnt seem called.

for privacy purpose have removed code displayed below give error if compiled, in actual code activity b , listviews call run fine .

please help! :)

my code:

import java.io.serializable; import java.util.arraylist;  import org.json.jsonobject; import android.os.bundle; import android.app.activity; import android.content.intent; import android.view.menu; import android.view.menuitem; import android.view.view; import android.view.view.onclicklistener;  public class main extends activity implements serializable,         onclicklistener {      // fetch  data in form of string url     public string internetdata;        public static arraylist<string> list;     public static boolean hasranonce;       @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          initialize();         // begin asynctask doinbackground          requestdata();     }      private void initialize() {         hasranonce = boolean.false;          list = new arraylist<string>();     }      private void requestdata() {             //string url, removed here          getmethodex requestobject = new getmethodex();         requestobject.setactivity(this);         requestobject.execute(string);     }      // function called onpostexecute of getmethodex     public void buildnodes() {          try {             // create json objects               rootnode = rootnode.createnode(jobject);              passlist.add(rootnode);         } catch (exception e) {             e.printstacktrace();         }      }      protected void startlist() {         // start new activity publishing results list         intent mylist = new intent(this, list.class);         mylist.putextra("passlist", passlist);         hasranonce = boolean.true;         startactivity(mylist);      } 

///##where facing problem possibly

    @override     public void onclick(view v) {           switch (v.getid()) {         case r.id.display:             startlist();         }     }      @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.activity_menu, menu);         return true;     }  } 

    try code    button.setonclicklistener(new onclicklistener() {                  public void onclick(view v) {                     // todo auto-generated method stub       intent mylist = new intent(this, list.class);             mylist.putextra("passlist", passlist);             hasranonce = boolean.true;             startactivity(mylist);                 }             });