Android:Facebook android application -

my facebook android application crashes everytime try run on emulator..i following code facebook webiste here https://developers.facebook.com/docs/tutorials/androidsdk/3.0/scrumptious/authenticate/

i tried other tutorials no matter use ...everytime crashes.. here code

package com.example.fblogin;  import com.facebook.session; import com.facebook.sessionstate; import com.facebook.uilifecyclehelper;  import android.os.bundle; import android.app.activity; import android.content.intent; import android.support.v4.app.fragment; import android.support.v4.app.fragmentactivity; import android.support.v4.app.fragmentmanager; import android.support.v4.app.fragmenttransaction; import android.view.menu;  public class mainactivity extends fragmentactivity { private static final int splash = 0; private static final int selection = 1; private static final int fragment_count = selection +1; private boolean isresumed = false; private uilifecyclehelper uihelper; private session.statuscallback callback =      new session.statuscallback() {     @override     public void call(session session,              sessionstate state, exception exception) {         onsessionstatechange(session, state, exception);     } };     private fragment[] fragments = new fragment[fragment_count]; @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     uihelper = new uilifecyclehelper(this, callback);     uihelper.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      fragmentmanager fm = getsupportfragmentmanager();     fragments[splash] = fm.findfragmentbyid(r.id.splashfragment);     fragments[selection] = fm.findfragmentbyid(r.id.selectionfragment);      fragmenttransaction transaction = fm.begintransaction();     for(int = 0; < fragments.length; i++) {         transaction.hide(fragments[i]);     }     transaction.commit(); }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; }  private void showfragment(int fragmentindex, boolean addtobackstack) {     fragmentmanager fm = getsupportfragmentmanager();     fragmenttransaction transaction = fm.begintransaction();     (int = 0; < fragments.length; i++) {         if (i == fragmentindex) {             transaction.show(fragments[i]);         } else {             transaction.hide(fragments[i]);         }     }     if (addtobackstack) {         transaction.addtobackstack(null);     }     transaction.commit(); }   @override public void onresume() {     super.onresume();     uihelper.onresume();     isresumed = true; }  @override public void onpause() {     super.onpause();     uihelper.onpause();     isresumed = false; } @override public void onactivityresult(int requestcode, int resultcode, intent data) {     super.onactivityresult(requestcode, resultcode, data);     uihelper.onactivityresult(requestcode, resultcode, data); }  @override public void ondestroy() {     super.ondestroy();     uihelper.ondestroy(); }  @override protected void onsaveinstancestate(bundle outstate) {     super.onsaveinstancestate(outstate);     uihelper.onsaveinstancestate(outstate); } private void onsessionstatechange(session session, sessionstate state,             exception      exception) {     // make changes if activity visible     if (isresumed) {         fragmentmanager manager = getsupportfragmentmanager();         // number of entries in stack         int backstacksize = manager.getbackstackentrycount();         // clear stack         (int = 0; < backstacksize; i++) {             manager.popbackstack();         }         if (state.isopened()) {             // if session state open:             // show authenticated fragment             showfragment(selection, false);         } else if (state.isclosed()) {             // if session state closed:             // show login fragment             showfragment(splash, false);         }     } }   @override protected void onresumefragments() {     super.onresumefragments();     session session = session.getactivesession();      if (session != null && session.isopened()) {         // if session open,         // try show selection fragment         showfragment(selection, false);     } else {         // otherwise present splash screen         // , ask user login.         showfragment(splash, false);     } } } 

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