java - How to refresh the fragment inside viewpager dynamically? -

i have 1 viewpager(mainviewpager) inside mainactivity renders fragment contains viewpager(imageviewpager) , textview. imageviewpager renders fragment contains imageview , button. i've set onclick listener on imageview turns in fullscreen view of image button beneath.now onclick of buttton want return mainactivity condition on same page entered , same image viewed last in fullscreen.i able same page image starts 0.

basically hierarchy like:

mainactivity    --mainviewpager-->taskfragment                         --imageviewpager-->imagefragment(contains imageview                         --textview(set text returned mainactivity) 

my code: mainactivity.java

    public class mainactivity extends fragmentactivity {          private viewpager mviewpager;         private custompageradapter mpageradapter;         private int changedposition;          private string[] vehicles = new string[]{"audi q7", "honda accord", "hyundai i20", "maruti suzuki swift", "mahindra xuv 500",                 "swift dzire", "honda city", "honda civic", "mercedez benz", "rolls royce", "ferrari"};          private string[][] vehicle_info = new string[][]{                 {"http://www.hdwallpapers.in/walls/2010_abt_audi_q7_3_tdi_3-wide.jpg",                         "http://www.hdwallpapers.in/walls/2010_mtm_audi_s5_cabrio_michelle_edition-wide.jpg",                         "http://www.hdwallpapers.in/walls/2009_audi_tts_coupe_car-wide.jpg"},                 {"http://automobiles.honda.com/images/2015/accord-sedan/exterior-gallery/2015-honda-accord-sedan-sport-exterior-side1.jpg",                         "http://www.carprousa.com/wp-content/uploads/2015/01/hondainterior-e1421978263126.jpg",                         "http://www.carprousa.com/wp-content/uploads/2015/01/hondainterior2-e1421978365916.jpg"},                 ........... };           @override         protected void oncreate(bundle savedinstancestate) {             super.oncreate(savedinstancestate);             setcontentview(r.layout.activity_main);              mviewpager = (viewpager)findviewbyid(r.id.mainviewpager);             mpageradapter = new custompageradapter(getsupportfragmentmanager(), vehicles, vehicle_info);             mviewpager.setadapter(mpageradapter);          }          @override         protected void onactivityresult(int requestcode, int resultcode, intent data) {             super.onactivityresult(requestcode, resultcode, data);             if (requestcode == 0) {                  changedposition = data.getintextra("changed_position", 0);                 log.i("position 3:"," "+changedposition);                  taskfragment fragment = new taskfragment();                 bundle bundle = new bundle();                 bundle.putint("image_position", changedposition);                 fragment.setarguments(bundle);             }         }      } 

activity_main.xml

 <android.support.v4.view.viewpager         android:id="@+id/mainviewpager"         android:layout_width="match_parent"         android:layout_height="match_parent" >      </android.support.v4.view.viewpager> 

custompageradapter.java

public class custompageradapter extends fragmentstatepageradapter{      private string[] vehicles,selected_vehicle_info;     private string[][] vehicle_info;      public custompageradapter(fragmentmanager fragmentmanager,string[] vehicles,string[][] vehicle_info){         super(fragmentmanager);         this.vehicles = vehicles;         this.vehicle_info = vehicle_info;     }      @override     public fragment getitem(int position) {          selected_vehicle_info = vehicle_info[position];          taskfragment taskfragment = new taskfragment();          bundle bundle = new bundle();         bundle.putstring("item",vehicles[position]);         bundle.putstringarray("item_info",selected_vehicle_info);         taskfragment.setarguments(bundle);          return taskfragment;     }      @override     public int getcount() {         return vehicles.length;     } } 

taskfragment.java

public class taskfragment extends fragment {      private string vehicle;     private string[] vehicle_info;     private viewpager imageviewpager;     private imagepageradapter imagepageradapter;     private int changedimageposition;       @nullable     @override     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {          vehicle = getarguments().getstring("item");         vehicle_info = getarguments().getstringarray("item_info");          view view = inflater.inflate(r.layout.activity_task_fragment,container,false);         textview messagetextview = (textview) view.findviewbyid(r.id.textview);         messagetextview.settext(vehicle);          imageviewpager = (viewpager)view.findviewbyid(r.id.imageviewpager);          imagepageradapter = new imagepageradapter(getactivity(), vehicle_info);         imagepageradapter.notifydatasetchanged();         imageviewpager.setadapter(imagepageradapter);         imageviewpager.setcurrentitem(changedimageposition);          return view;     }      private class imagepageradapter extends pageradapter {          private activity activity;         private string[] vehicle_info;          public imagepageradapter(activity activity,string[] vehicle_info){             this.activity = activity;             this.vehicle_info = vehicle_info;         }          @override         public object instantiateitem(viewgroup container, final int position) {              layoutinflater inflater = layoutinflater.from(activity);             view view = inflater.inflate(r.layout.activity_image_fragment,container,false);             imageview imageview = (imageview) view.findviewbyid(r.id.imageview);              picasso.with(getcontext()).load(vehicle_info[position]).into(imageview);              if(imageview.getparent()!=null)                 ((viewgroup)imageview.getparent()).removeview(imageview);              ((viewpager) container).addview(imageview, 0);              imageview.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     intent intent = new intent(activity, imageinfullscreen.class);                     intent.putextra("images_url", vehicle_info);                     intent.putextra("image_position", position);                     activity.startactivityforresult(intent, 0);                 }             });             return imageview;         }          @override         public int getitemposition(object object) {             return position_none;         }          @override         public int getcount() {             return vehicle_info.length;         }          @override         public void destroyitem(viewgroup collection, int position, object view) {             collection.removeview((view) view);         }          @override         public boolean isviewfromobject(view view, object object) {             return view == object;         }     }  } 

imageinfullscreen.java

button.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 intent intent=new intent();                 intent.putextra("changed_position",changedimgposition);                 setresult(0,intent);}}); 

//and same adapter n all.

where ever want refresh view put following code

this.page_position = 0; imagepageradapter.notifydatasetchanged(); 

and in imagepageradapter override following function -

@override     public int getitemposition(object object) {         return position_none;     } 

position_none means whenever notifydatasetchanged called, adapter create fresh views rather using same views.

this should work in our case.