How do I use UIPageViewController to load separate XIBs?

Question

I'm delving into the new world of UIPageViewControllers and there are a lot of tutorials out there, however all of them seem to create one view, and then just use new instances of it with different content.

I'd really like to be able to create multiple XIBs and then just chain them together with the UIPageViewController but it's too new and I can't get my head around the way it works.

Answer 1

Well, here's a long answer that you should be able to copy and paste. (This code was adapted from Erica Sadun (https://github.com/erica/iOS-5-Cookbook))

First, create a new class of type UIPageViewController. Call it BookController. Now paste the following code in your .h file.

// Used for storing the most recent book page used
#define DEFAULTS_BOOKPAGE   @"BookControllerMostRecentPage"

@protocol BookControllerDelegate <NSObject>
- (id) viewControllerForPage: (int) pageNumber;
@optional
- (void) bookControllerDidTurnToPage: (NSNumber *) pageNumber;
@end

@interface BookController : UIPageViewController <UIPageViewControllerDelegate, UIPageViewControllerDataSource>
+ (id) bookWithDelegate: (id) theDelegate;
+ (id) rotatableViewController;
- (void) moveToPage: (uint) requestedPage;
- (int) currentPage;

@property (assign) id <BookControllerDelegate> bookDelegate;
@property (nonatomic, assign) uint pageNumber;

and in your .m file:

#define IS_IPHONE   ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
#define SAFE_ADD(_Array_, _Object_) {if (_Object_ && [_Array_ isKindOfClass:[NSMutableArray class]]) [pageControllers addObject:_Object_];}
#define SAFE_PERFORM_WITH_ARG(THE_OBJECT, THE_SELECTOR, THE_ARG) (([THE_OBJECT respondsToSelector:THE_SELECTOR]) ? [THE_OBJECT performSelector:THE_SELECTOR withObject:THE_ARG] : nil)


#pragma Utility Class - VC that Rotates
@interface RotatableVC : UIViewController 
@end
@implementation RotatableVC
- (void) loadView 
{
    [super loadView]; 
    self.view.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
    self.view.backgroundColor = [UIColor whiteColor];
}
- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation 
{
    return YES;
}
@end


#pragma Book Controller
@implementation BookController
@synthesize bookDelegate, pageNumber;

#pragma mark Debug / Utility
- (int) currentPage
{
    int pageCheck = ((UIViewController *)[self.viewControllers objectAtIndex:0]).view.tag;
    return pageCheck;
}

#pragma mark Page Handling

// Update if you'd rather use some other decision style
- (BOOL) useSideBySide: (UIInterfaceOrientation) orientation
{
    BOOL isLandscape = UIInterfaceOrientationIsLandscape(orientation);
    return isLandscape;
}

// Store the new page and update the delegate
- (void) updatePageTo: (uint) newPageNumber
{   
    pageNumber = newPageNumber;

    [[NSUserDefaults standardUserDefaults] setInteger:pageNumber forKey:DEFAULTS_BOOKPAGE];
    [[NSUserDefaults standardUserDefaults] synchronize];

    SAFE_PERFORM_WITH_ARG(bookDelegate, @selector(bookControllerDidTurnToPage:), [NSNumber numberWithInt:pageNumber]);

}

// Request controller from delegate
- (UIViewController *) controllerAtPage: (int) aPageNumber
{
    if (bookDelegate && 
        [bookDelegate respondsToSelector:@selector(viewControllerForPage:)])
    {
        UIViewController *controller = [bookDelegate viewControllerForPage:aPageNumber];
        controller.view.tag = aPageNumber;
        return controller;
    }
    return nil;
}

// Update interface to the given page
- (void) fetchControllersForPage: (uint) requestedPage orientation: (UIInterfaceOrientation) orientation
{
    BOOL sideBySide = [self useSideBySide:orientation];
    int numberOfPagesNeeded = sideBySide ? 2 : 1;
    int currentCount = self.viewControllers.count;

    uint leftPage = requestedPage;
    if (sideBySide && (leftPage % 2)) leftPage--;

    // Only check against current page when count is appropriate
    if (currentCount && (currentCount == numberOfPagesNeeded))
    {
        if (pageNumber == requestedPage) return;
        if (pageNumber == leftPage) return;
    }

    // Decide the prevailing direction by checking the new page against the old
    UIPageViewControllerNavigationDirection direction = (requestedPage > pageNumber) ? UIPageViewControllerNavigationDirectionForward : UIPageViewControllerNavigationDirectionReverse;
    [self updatePageTo:requestedPage];

    // Update the controllers
    NSMutableArray *pageControllers = [NSMutableArray array];
    SAFE_ADD(pageControllers, [self controllerAtPage:leftPage]);    
    if (sideBySide)
        SAFE_ADD(pageControllers, [self controllerAtPage:leftPage + 1]);

    [self setViewControllers:pageControllers direction: direction animated:YES completion:nil];
}

// Entry point for external move request
- (void) moveToPage: (uint) requestedPage
{
    [self fetchControllersForPage:requestedPage orientation:(UIInterfaceOrientation)[UIDevice currentDevice].orientation];
}

#pragma mark Data Source

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    [self updatePageTo:pageNumber + 1];
    return [self controllerAtPage:(viewController.view.tag + 1)];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
    [self updatePageTo:pageNumber - 1];
    return [self controllerAtPage:(viewController.view.tag - 1)];
}

#pragma mark Delegate

- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation
{
    NSUInteger indexOfCurrentViewController = 0;
    if (self.viewControllers.count)
        indexOfCurrentViewController = ((UIViewController *)[self.viewControllers objectAtIndex:0]).view.tag;
    [self fetchControllersForPage:indexOfCurrentViewController orientation:orientation];

    BOOL sideBySide = [self useSideBySide:orientation];
    self.doubleSided = sideBySide;

    UIPageViewControllerSpineLocation spineLocation = sideBySide ? UIPageViewControllerSpineLocationMid : UIPageViewControllerSpineLocationMin;
    return spineLocation;
}

-(void)dealloc{
    self.bookDelegate = nil;
}

#pragma mark Class utility routines
// Return a UIViewController that knows how to rotate
+ (id) rotatableViewController
{
    UIViewController *vc = [[RotatableVC alloc] init];
    return vc;
}

// Return a new book
+ (id) bookWithDelegate: (id) theDelegate
{
    BookController *bc = [[BookController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];

    bc.dataSource = bc;
    bc.delegate = bc;
    bc.bookDelegate = theDelegate;

    return bc;
}

This Class can now be used to control any book you create in any project, and for multiple books in a single project. For each book, create a delegate UIPageViewController with the @interface:

@interface NameOfBookController : UIPageViewController <BookControllerDelegate>

In the .m file of this delegate, include:

// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView
{
    [super loadView];
    CGRect appRect = [[UIScreen mainScreen] applicationFrame];
    self.view = [[UIView alloc] initWithFrame: appRect];
    self.view.backgroundColor = [UIColor whiteColor];
    self.view.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

    // Establish the page view controller
    bookController = [BookController bookWithDelegate:self];
    bookController.view.frame = (CGRect){.size = appRect.size};
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    // Add the child controller, and set it to the first page
    [self.view addSubview:bookController.view];
    [self addChildViewController:bookController];
    [bookController didMoveToParentViewController:self];
}

Then add:

- (id) viewControllerForPage: (int) pageNumber
{    

    // Establish a new controller

    UIViewController *controller;


    switch (pageNumber) {
        case 0:
            view1 = [[FirstViewController alloc] init];
            view1.view.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
            controller = view1;
//rinse and repeat with each new view controller
            break;
        case 1:
            //etc.
            break;
        default:
            return nil;
            break;
    }
    return controller;
}

For the record, this code is not memory-safe. If using ARC, add in your @autoreleasePool{}; if not, don't forget your retain/release cycle.

I hope this helps!