java - NullPointerException thrown from Fragment -

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• what nullpointerexception, , how fix it? 12 answers

here's fragment class code has logout button.

import android.app.fragment; import android.content.intent; import android.os.bundle; import android.view.layoutinflater; import android.view.view; import android.view.viewgroup; import android.widget.button;  import com.marshall.gruppo.r; import com.marshall.gruppo.helper.sqlitehandler; import com.marshall.gruppo.helper.sessionmanager;  public class mypagefragment extends fragment implements view.onclicklistener {      button logout;     view view;     sessionmanager session;     sqlitehandler db;      public mypagefragment(){}      @override     public view oncreateview(layoutinflater inflater, viewgroup container,                              bundle savedinstancestate) {         view rootview = inflater.inflate(r.layout.fragment_mypage, container, false);         logout = (button) view.findviewbyid(r.id.logout);         logout.setonclicklistener(this);         return rootview;     }      @override     public void onclick(view v) {         switch(v.getid()) {             case r.id.logout:                 logoutuser();                 break;         }     }     private void logoutuser() {         session.setlogin(false);         db.deleteusers();         intent intent = new intent(getactivity().getapplicationcontext(), loginactivity.class);         startactivity(intent);         getactivity().finish();     } } 

but when run code, throws nullpointerexception following log.

07-10 13:03:25.521  13363-13363/com.marshall.gruppo e/androidruntime﹕ fatal exception: main     process: com.marshall.gruppo, pid: 13363     java.lang.nullpointerexception             @ com.marshall.gruppo.ui.mypagefragment.oncreateview(mypagefragment.java:28)             @ android.app.fragment.performcreateview(fragment.java:1700)             @ android.app.fragmentmanagerimpl.movetostate(fragmentmanager.java:890)             @ android.app.fragmentmanagerimpl.movetostate(fragmentmanager.java:1062)             @ android.app.backstackrecord.run(backstackrecord.java:684)             @ android.app.fragmentmanagerimpl.execpendingactions(fragmentmanager.java:1453)             @ android.app.fragmentmanagerimpl$1.run(fragmentmanager.java:443)             @ android.os.handler.handlecallback(handler.java:733)             @ android.os.handler.dispatchmessage(handler.java:95)             @ android.os.looper.loop(looper.java:146)             @ android.app.activitythread.main(activitythread.java:5602)             @ java.lang.reflect.method.invokenative(native method)             @ java.lang.reflect.method.invoke(method.java:515)             @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1283)             @ com.android.internal.os.zygoteinit.main(zygoteinit.java:1099)             @ dalvik.system.nativestart.main(native method) 

when writing code did not show errors, wonder has fault.. according log, part throws exception.

logout = (button) view.findviewbyid(r.id.logout); 

any advice on issue?

in code using view.findviewbyid. here view null. that's why getting nullpointerexception.

instead of code:

view rootview = inflater.inflate(r.layout.fragment_mypage, container, false);

    logout = (button) view.findviewbyid(r.id.logout); 

try code:

view rootview = inflater.inflate(r.layout.fragment_mypage, container, false);         logout = (button) rootview.findviewbyid(r.id.logout);