how to add two view controllers in UIPageViewcontroller

I m using `UIPageViewController` on iPad where I need to show a `firstviewController` in the first page and `ContentViewController` in the next page in landscape. If I set the `NSArray` with two `viewControllers` the app is crashes at `[self.pagviewController setViewController:]` with the following exception: The number of provided view controllers (2) doesn't match the number required (1) for the requested spine location (UIPageViewControllerSpineLocationMin) Below is the code: ``` #pragma mark - UIPageViewControllerDataSource Methods - (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController { NSUInteger currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)viewController textContents]]; if(currentIndex == 0) { return nil; } ContentViewController *contentViewController = [[ContentViewController alloc] init]; contentViewController.textContents = [self.modelArray objectAtIndex:currentIndex - 1]; return contentViewController; } - (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController { NSUInteger currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)viewController textContents]]; if(currentIndex == self.modelArray.count-1) { return nil; } ContentViewController *contentViewController = [[ContentViewController alloc] init]; contentViewController.textContents = [self.modelArray objectAtIndex:currentIndex + 1]; return contentViewController; } //#pragma mark - UIPageViewControllerDelegate Methods - (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation { if(UIInterfaceOrientationIsPortrait(orientation)) { //Set the array with only 1 view controller UIViewController *currentViewController = [self.pageViewController.viewControllers objectAtIndex:0]; NSArray *viewControllers = [NSArray arrayWithObject:currentViewController]; [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL]; //Important- Set the doubleSided property to NO. self.pageViewController.doubleSided = NO; //Return the spine location return UIPageViewControllerSpineLocationMin; } else { NSArray *viewControllers = nil; ContentViewController *currentViewController = [self.pageViewController.viewControllers objectAtIndex:0]; NSUInteger currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)currentViewController textContents]]; if(currentIndex == 0 || currentIndex %2 == 0) { UIViewController *nextViewController = [self pageViewController:self.pageViewController viewControllerAfterViewController:currentViewController]; viewControllers = [NSArray arrayWithObjects:currentViewController, nextViewController, nil]; } else { UIViewController *previousViewController = [self pageViewController:self.pageViewController viewControllerBeforeViewController:currentViewController]; viewControllers = [NSArray arrayWithObjects:previousViewController, currentViewController, nil]; } //Now, set the viewControllers property of UIPageViewController [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL]; return UIPageViewControllerSpineLocationMid; } } - (void)viewDidLoad { [super viewDidLoad]; appDelegate = (AppDelegate *) [[UIApplication sharedApplication] delegate]; //Instantiate the model array self.modelArray = [[NSMutableArray alloc] init]; self.vcs = [[NSMutableArray alloc]init]; for (int index = 1; index <= 2 ; index++) { [self.modelArray addObject:[NSString stringWithFormat:@"Page %d",index]]; } //Step 1 //Instantiate the UIPageViewController. self.pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil]; //Step 2: //Assign the delegate and datasource as self. self.pageViewController.delegate = self; self.pageViewController.dataSource = self; //Step 3: //Set the initial view controllers. appDelegate.contentViewController.textContents = [self.modelArray objectAtIndex:0]; NSArray *viewControllers = [NSArray arrayWithObjects:appDelegate.firstViewController,appDelegate.contentViewController,nil]; [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil]; //Step 4: //ViewController containment steps //Add the pageViewController as the childViewController [self addChildViewController:self.pageViewController]; //Add the view of the pageViewController to the current view [self.view addSubview:self.pageViewController.view]; //Call didMoveToParentViewController: of the childViewController, the UIPageViewController instance in our case. [self.pageViewController didMoveToParentViewController:self]; //Step 5: // set the pageViewController's frame as an inset rect. CGRect pageViewRect = self.view.bounds; pageViewRect = CGRectInset(pageViewRect, 40.0, 40.0); self.pageViewController.view.frame = pageViewRect; //Step 6: //Assign the gestureRecognizers property of our pageViewController to our view's gestureRecognizers property. self.view.gestureRecognizers = self.pageViewController.gestureRecognizers; } ```