android - How do I prevent viewpager from making network request, if the network request has already been made for all the pages -

i have viewpager 3 pages uses fragmentstatepageradapter. fragment each page same data changes depending on position of page. inflation logic each item on page defined in fragment's oncreateview, , thats why each time new instance of fragment inflated network calls repeated though have been made on previous visit page.

my question how prevent this. new android , know missing here, if approach wrong please point out how should prevent behavior.

some code : inside activity's oncreate

    viewpager mviewpager = (viewpager) findviewbyid(r.id.vpbooks);     pageradapter mpageradapter = new bookspageadapter(getsupportfragmentmanager(), mainactivity.this, extras);     mviewpager.setadapter(mpageradapter); 

inside viewpageradapter

public bookspageadapter(fragmentmanager fm, context context, bundle extras) {     super(fm);     this.extras = extras;     this.cls = extras.getstringarray("cls");     this.context = context; }  @override public fragment getitem(int position) {     return bookspagefrag.newinstance(extras, cls[position]); }  @override public int getcount() {     return cls.length; } 

inside fragment :

@override public void oncreateview(bundle savedinstancestate) {     super.oncreate(savedinstancestate);      url = getarguments().getstring("url");     urlfare = getarguments().getstring("fare");     log.d("url sapf", url);     queue = volley.newrequestqueue(this.getactivity());     getbooks();// here network calls made } 

so want if fragement particular cls[position] instantiated , data fetched on revisiting same position should not make new network calls

you need use parcelable . think using list array of class object .follow following steps

1.) implement parcelable in class object
2.)in onsavedinstancestate use following code

 @override public void onsaveinstancestate(bundle outstate) {     super.onsaveinstancestate(outstate);     outstate.putparcelablearraylist("key", mlistparcel); }` 

3.) in oncreate method use code

@override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {     super.oncreateview(inflater, container, savedinstancestate);    /*set recyclerview stuff here*/    if(savedinstancestate!=null)     {          //fragment has been loaded earlier\          marraylist=savedinstancestate.getparcelablearraylist("key");          //use list here       }     else     {          //fragment new          // make request here     } }