android - Nullpointer exception while adding the banner Ad -

i trying display banner ad in game using revmob display both banner ad , fullscreen ad. full screen ads displaying banner ad not displaying getting null poinet exception in view.addview(banner).

enter code herepublic class mainactivity extends activity { private ccglsurfaceview mglsurfaceview; private boolean iscreated = false; public static framelayout m_rootlayout;  public static string application_id = "514c7c57cee0500d00000001"; public static revmob revmob;  // used display toast messages , not necessary app @override protected void oncreate(bundle savedinstancestate) {     if (!iscreated) {         iscreated = true;     } else {         return;     }      super.oncreate(savedinstancestate);      setrequestedorientation(activityinfo.screen_orientation_portrait);     requestwindowfeature(window.feature_no_title);     getwindow().setflags(windowmanager.layoutparams.flag_fullscreen,             windowmanager.layoutparams.flag_fullscreen);      setcontentview(r.layout.activity_main);      revmob = revmob.start(this, application_id);     displayrevmob();       mglsurfaceview = new ccglsurfaceview(this);     setcontentview(mglsurfaceview);       ccdirector.shareddirector().attachinview(mglsurfaceview);      getscaledcoordinate();      global.assetmanager = getassets();     global.context = this;     global.loaduserinfo();     ccscene scene = ccscene.node();     scene.addchild(new splashscene(), -1);      ccdirector.shareddirector().runwithscene(scene);         //-------------iap-----------------------     log.d(tag1, "creating iab helper.");         mhelper = new iabhelper(this, base64encodedpublickey);         mhelper.enabledebuglogging(true);         log.d(tag1, "starting setup.");         mhelper.startsetup(new iabhelper.oniabsetupfinishedlistener() {             public void oniabsetupfinished(iabresult result) {                 log.d(tag, "setup finished.");                  if (!result.issuccess()) {                     // oh noes, there problem.                     complain("problem setting in-app billing: " + result);                     return;                 }                  // hooray, iab set up. now, let's inventory of stuff own.                 log.d(tag, "setup successful. querying inventory.");                 mhelper.queryinventoryasync(mgotinventorylistener);             }         });         revmobbanner banner = revmob.createbanner(this);        viewgroup view = (viewgroup) findviewbyid(r.id.banner);        view.addview(banner);   }    public void displayrevmob(){     revmob.showfullscreen(this);    }   } 

logcat:

    04-20 14:05:53.591: e/androidruntime(1066): fatal exception: main 04-20 14:05:53.591: e/androidruntime(1066): java.lang.runtimeexception: unable start activity componentinfo{com.game.puzzlegame/com.game.puzzlegame.mainactivity}: java.lang.nullpointerexception 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread.performlaunchactivity(activitythread.java:1956) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:1981) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread.access$600(activitythread.java:123) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread$h.handlemessage(activitythread.java:1147) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.os.handler.dispatchmessage(handler.java:99) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.os.looper.loop(looper.java:137) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread.main(activitythread.java:4424) 04-20 14:05:53.591: e/androidruntime(1066):     @ java.lang.reflect.method.invokenative(native method) 04-20 14:05:53.591: e/androidruntime(1066):     @ java.lang.reflect.method.invoke(method.java:511) 04-20 14:05:53.591: e/androidruntime(1066):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:784) 04-20 14:05:53.591: e/androidruntime(1066):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:551) 04-20 14:05:53.591: e/androidruntime(1066):     @ dalvik.system.nativestart.main(native method) 04-20 14:05:53.591: e/androidruntime(1066): caused by: java.lang.nullpointerexception 04-20 14:05:53.591: e/androidruntime(1066):     @ com.game.puzzlegame.mainactivity.oncreate(mainactivity.java:122) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activity.performcreate(activity.java:4465) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1049) 04-20 14:05:53.591: e/androidruntime(1066):     @ android.app.activitythread.performlaunchactivity(activitythread.java:1920) 04-20 14:05:53.591: e/androidruntime(1066):     ... 11 more 

xml

<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  android:orientation="vertical" >   <linearlayout android:id="@+id/banner"            android:layout_width="wrap_content"            android:layout_height="wrap_content" >  </linearlayout>  </linearlayout> 

the problem in here:

viewgroup view = (viewgroup) findviewbyid(r.id.banner); view.addview(banner); 

apparently findviewbyid() returns null, means view called banner not found in xml layout file.

you have r.layout.activity_main set content view. ensure, have view banner id in file.