android - View is null in Fragment -

i have number of fragments within viewpager in 1 of activities. these fragments have text on them. goal update text on fragments when event happens in activity.

i have tried things, cannot seem find view work with. in below code have tried save view oncreateview private field. works when creating fragment, when try , call refresh mview null.

refresh implemented in interface. viewpager has 2 different fragments, implemented interface allow me cast unknown fragment call refresh.

i have tried write below code best illustrate problem. can set text "hello" on refresh, activity crash because mview null.

    private view mview = null;      @override     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {         if (container == null) { return null; }                  view view = inflater.inflate(r.layout.view_account_general, container, false);         mview = view;         setcontent();         return view;     }      private void setcontent() {         if (mview == null) return;         ((textview) mview.findviewbyid(r.id.mid)).settext("hello");     }      @override     public void refresh() {         ((textview) mview.findviewbyid(r.id.mid)).settext("test");     } 

what doing wrong , should doing instead? fragments new me , haven't programmed android in long time. intention update value of textview when refresh method called.

thank attempts @ helping me issue!

edit: requested, exception trace.

fatal exception: main java.lang.nullpointerexception     @ com.jordanmoore.finances.accountgeneralfragment.refresh(accountgeneralfragment.java:85)     @ com.jordanmoore.finances.accountactivity.onoptionsitemselected(accountactivity.java:222)     @ android.app.activity.onmenuitemselected(activity.java:2534)     @ android.support.v4.app.fragmentactivity.onmenuitemselected(fragmentactivity.java:361)     @ com.android.internal.policy.impl.phonewindow.onmenuitemselected(phonewindow.java:964)     @ com.android.internal.view.menu.menubuilder.dispatchmenuitemselected(menubuilder.java:735)     @ com.android.internal.view.menu.menuitemimpl.invoke(menuitemimpl.java:149)     @ com.android.internal.view.menu.menubuilder.performitemaction(menubuilder.java:874)     @ com.android.internal.view.menu.menupopuphelper.onitemclick(menupopuphelper.java:156)     @ android.widget.adapterview.performitemclick(adapterview.java:298)     @ android.widget.abslistview.performitemclick(abslistview.java:1090)     @ android.widget.abslistview$performclick.run(abslistview.java:2863)     @ android.widget.abslistview$1.run(abslistview.java:3538)     @ android.os.handler.handlecallback(handler.java:615)     @ android.os.handler.dispatchmessage(handler.java:92)     @ android.os.looper.loop(looper.java:213)     @ android.app.activitythread.main(activitythread.java:4786)     @ java.lang.reflect.method.invokenative(native method)     @ java.lang.reflect.method.invoke(method.java:511)     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:789)     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:556)     @ dalvik.system.nativestart.main(native method) 

bottom line- fragment should in control of refreshing it's own view. activity should never call "refresh" method in fragment, because it's painful , error-prone determine when fragment initialized , ready render.

in case, activity broadcast "update", fragments register receive. long ensure register after preconditions have been met, , unregister before preconditions become invalid, things work. e.g., follow typical pattern of registering in onresume() on unregistering in onpause().