UIPageViewController call zoom X1 before viewControllerAfterViewController - ios

Question

I want to reset zoom factor applied to imageView/scrollView before calling viewControllerAfterViewController.
I have an UIPageViewController "SecondViewController" and another UIViewController "ImageViewController". To explain hierarchy I prefer show some code :
#import "ImageViewController.h"
#import "SecondViewController.h"
#interface SecondViewController ()
#end
#implementation SecondViewController
#synthesize pageViewController;
#synthesize imgModelArray;
- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController
{
return imgModelArray.count;
}
- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
{
return 0;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[[self view] setBackgroundColor:[UIColor colorWithRed: 40/255.0 green:40/255.0 blue:40/255.0 alpha:1.0]];
// Init model and pageViewController
self.imgModelArray = [NSMutableArray arrayWithObjects:
[[ImageModel alloc] initWith:#"piaggo.jpg":#"softCat"],
[[ImageModel alloc] initWith:#"crumble.jpg":#"funnyDog"],
[[ImageModel alloc] initWith:#"piaggo.jpg":#"sleepingCat"],
[[ImageModel alloc] initWith:#"crumble.jpg":#"goodDog"],
[[ImageModel alloc] initWith:#"piaggo.jpg":#"softCat"],
[[ImageModel alloc] initWith:#"crumble.jpg":#"funnyDog"],
[[ImageModel alloc] initWith:#"piaggo.jpg":#"sleepingCat"],
[[ImageModel alloc] initWith:#"crumble.jpg":#"goodDog"], nil];
self.pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll
navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal
options:[NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:50.0f] forKey:UIPageViewControllerOptionInterPageSpacingKey]];
self.pageViewController.delegate = self;
self.pageViewController.dataSource = self;
// Init ImageViewController - Load Model - Create page 1
ImageViewController *imageViewController = [[ImageViewController alloc] init];
imageViewController.model = [imgModelArray objectAtIndex:0];
NSArray *viewControllers = [NSArray arrayWithObject:imageViewController];
[self.pageViewController setViewControllers:viewControllers
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:nil];
[self addChildViewController:pageViewController];
[self.view addSubview:pageViewController.view];
[pageViewController didMoveToParentViewController:self];
self.view.gestureRecognizers = pageViewController.gestureRecognizers;
}
// Return an ImageViewController with previous data model
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)vcFrom
{
ImageViewController *imgVc = (ImageViewController *)vcFrom;
NSUInteger currentIndex = [imgModelArray indexOfObject:[imgVc model]];
if (currentIndex == 0)
{
return nil;
}
ImageViewController *previousImgViewController = [[ImageViewController alloc] init];
previousImgViewController.model = [imgModelArray objectAtIndex:currentIndex - 1];
return previousImgViewController;
}
// Return an ImageViewController with next data model
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)vcFrom
{
ImageViewController *imgVc = (ImageViewController *)vcFrom;
[imgVc zoomX1];
NSUInteger currentIndex = [imgModelArray indexOfObject:[imgVc model]];
if (currentIndex == imgModelArray.count - 1)
{
return nil;
}
ImageViewController *nextImgViewController = [[ImageViewController alloc] init];
nextImgViewController.model = [imgModelArray objectAtIndex:currentIndex + 1];
return nextImgViewController;
}
#end
I want to call zoomX1 method (localized in ImageViewController.m), just before this one : "viewControllerAfterViewController"
What kind of event could do this ?
zoomX1 work well excepted when I am using viewControllerAfterViewController.
When I call zoomx1 inside "viewControllerAfterViewController", my view is disappearing...
But the values for height and width are not 0. Help me please !
In ImageViewController.m : zoomX1
- (void)zoomX1{
// Figure out the rect we want to zoom to, then zoom to X1
UIImage *currentImage = [UIImage imageNamed:model.imageName];
CGSize currentImgSize = currentImage.size;
CGFloat w = currentImgSize.width;
CGFloat h = currentImgSize.height;
CGFloat x = 0;
CGFloat y = 0;
CGRect rectToZoomTo = CGRectMake(x, y, w, h);
[self.scrollView zoomToRect:rectToZoomTo animated:YES];
}
EDITED (2X) :
I think I have a problem with UIPanGestureRecognizer.
In "SecondViewController.view" and "pageViewController" : PanGesture is used to move to next/previous "ImageViewController" with "viewControllerAfterViewController" and "viewControlleBeforeViewController"
In "ImageViewController.scrollView" : PanGesture is used to move to a specific area when I zoomed on an image.
I didn't add programmatically a PanGesture. I just want to keep the panGesture inside scrollView which is reponsible of moving inside an Image. And keep the other panGesture linked at view level which is responsible of switching page. I think they are private Apple's method.
But when I pan inside scrollView there is a problem.

Answer 1

I had a similar problem in one of my projects and what I did I added an extra target to the UISwipeGestureRecognizer of the UIPageViewController. You can try this (it may be a considered by other developers a hack but I don't think so).
In viewDidLoad or other init/setup methods you can try something like this:
for(UIGestureRecognizer *gesture in yourPageViewController.gestureRecognizers) {
if([gesture isKindOfClass:[UISwipeGestureRecognizer class]]) {
[gesture addTarget:self action:#selector(zoomX1)]
}
}