IOS facebook login using Xcode 5.1 - ios

Question

I have followed the instructions to integrate Facebook login in iOS from here. It worked initially and I was able to login but then it started showing a blank white screen in safari browser(I'm testing it on simulator). I have cleared the cache and and also unblock the cookies.Please help if anyone knows the solution.
Below is the code that I 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];
// Do any additional setup after loading the view, typically from a 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 any resources that can be recreated.
}
// This method will be called when the 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 that can occur during login
- (void)loginView:(FBLoginView *)loginView handleError:(NSError *)error {
NSString *alertMessage, *alertTitle;
// If the user should perform an action outside of you app to recover,
// the SDK will provide a message for the user, you just need to surface it.
// This conveniently handles cases like Facebook password change or unverified Facebook accounts.
if ([FBErrorUtility shouldNotifyUserForError:error]) {
alertTitle = #"Facebook error";
alertMessage = [FBErrorUtility userMessageForError:error];
// This code will handle session closures that happen outside of the app
// You can take a look at our error handling guide to know more about it
// https://developers.facebook.com/docs/ios/errors
} else if ([FBErrorUtility errorCategoryForError:error] == FBErrorCategoryAuthenticationReopenSession) {
alertTitle = #"Session Error";
alertMessage = #"Your current session is no longer valid. Please log in again.";
// If the user has cancelled a login, we will do nothing.
// You can also choose to show the user a message if cancelling login will result in
// the user not being able to complete a task they had initiated in your app
// (like accessing FB-stored information or posting to Facebook)
} else if ([FBErrorUtility errorCategoryForError:error] == FBErrorCategoryUserCancelled) {
NSLog(#"user cancelled login");
// For simplicity, this sample handles other errors with a generic message
// You can checkout our error handling guide for 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