IOS facebook login using Xcode 5.1 -

i have followed instructions integrate facebook login in ios here. worked , able login started showing blank white screen in safari browser(i'm testing on simulator). have cleared cache , and unblock cookies.please if knows solution.

below code used in loginviewcontroller:

#import "viewcontroller.h" #import <facebooksdk/facebooksdk.h>  @interface viewcontroller () @property (strong, nonatomic) iboutlet fbprofilepictureview *profilepictureview; @property (strong, nonatomic) iboutlet uilabel *namelabel; @property (strong, nonatomic) iboutlet uilabel *statuslabel; @end  @implementation viewcontroller  - (void)viewdidload {     [super viewdidload];     // additional setup after loading view, typically nib.     fbloginview *loginview = [[fbloginview alloc] initwithreadpermissions:@[@"basic_info", @"email", @"user_likes"]];     loginview.frame = cgrectoffset(loginview.frame, (self.view.center.x - (loginview.frame.size.width / 2)), 5);     loginview.delegate = self;     [self.view addsubview:loginview]; }  - (void)didreceivememorywarning {     [super didreceivememorywarning];     // dispose of resources can recreated. } // method called when user information has been fetched - (void)loginviewfetcheduserinfo:(fbloginview *)loginview                             user:(id<fbgraphuser>)user {     self.profilepictureview.profileid = user.id;     self.namelabel.text = user.name; } // logged-in user experience - (void)loginviewshowingloggedinuser:(fbloginview *)loginview {     self.statuslabel.text = @"you're logged in as"; } // logged-out user experience - (void)loginviewshowingloggedoutuser:(fbloginview *)loginview {     self.profilepictureview.profileid = nil;     self.namelabel.text = @"";     self.statuslabel.text= @"you're not logged in!"; } // handle possible errors can occur during login - (void)loginview:(fbloginview *)loginview handleerror:(nserror *)error {     nsstring *alertmessage, *alerttitle;      // if user should perform action outside of app recover,     // sdk provide message user, need surface it.     // conveniently handles cases facebook password change or unverified facebook accounts.     if ([fberrorutility shouldnotifyuserforerror:error]) {         alerttitle = @"facebook error";         alertmessage = [fberrorutility usermessageforerror:error];          // code handle session closures happen outside of app         // can take @ our error handling guide know more         // https://developers.facebook.com/docs/ios/errors     } else if ([fberrorutility errorcategoryforerror:error] == fberrorcategoryauthenticationreopensession) {         alerttitle = @"session error";         alertmessage = @"your current session no longer valid. please log in again.";          // if user has cancelled login, nothing.         // can choose show user message if cancelling login result in         // user not being able complete task had initiated in app         // (like accessing fb-stored information or posting facebook)     } else if ([fberrorutility errorcategoryforerror:error] == fberrorcategoryusercancelled) {         nslog(@"user cancelled login");          // simplicity, sample handles other errors generic message         // can checkout our error handling guide more detailed information         // https://developers.facebook.com/docs/ios/errors     } else {         alerttitle  = @"something went wrong";         alertmessage = @"please try again later.";         nslog(@"unexpected error:%@", error);     }      if (alertmessage) {         [[[uialertview alloc] initwithtitle:alerttitle                                     message:alertmessage                                    delegate:nil                           cancelbuttontitle:@"ok"                           otherbuttontitles:nil] show];     } }  @end