iosobjective-cuipageviewcontrolleriphone-6pagecontrol

Strange behavior of Page View Controller on iPhone 6 and iPhone 6 Plus


I trying to implement page view controller with three pages. I already did it, it works very well on iPhones with 3.5- and 4-inch displays, but something wrong happens with 4.7- and 5.5-inch displays.

I found that hiding of standard Page Control of UIPageViewController is reason of this bug: when page control gets hidden the view of UIPageVC changes his height (+ height of Page Control View).

My page content view controllers has constraints for background image view to fit to all sizes.

This is first page: This is first page

This is second page: This is second page

This is third page, ok, we've reached last page: This is third page

But look what happens when we return to the second page (View of page content controller fully moved at few pixels to the left): This is again second page

Swipe to the first page - the same result: This is again first page

BUT! Look what we have when after the first page we go to the second page! Now view of page content controller at the right position by x: This is second page

Go to the last page: This is the last page

Let's come back to the second page! Holy ****! View gets moved by something again: This is the second page

Go to the first page, all in the 'right' (BAD) positions: This is the first page

Go back to the second page from first page. All in the good and right positions: This is the second page

So, my question is what is going on with this UIPageViewController? I thought that my constraints gets broken but I have nothing in my logs about it, in storyboard there are no error related to constraints.

When I use two methods "presentationCountForPageViewController:, presentationIndexForPageViewController:" all is good but above the button appears a white line of height equal to Page Control view's height (so, I need to hide it by erasing two methods listed above).

Thanks in advance for you future suggestions!


Solution

  • I fixed it! But not by the right way because it is iOS-side bug.

    So, when you trying to hide Page Control View of your UIPageViewController the private 'pageSpacing' property gets broken on iPhone 6 and iPhone 6 Plus by unexpected reason. It is hard to see and understand it from views. In my case for iPhone 6 InterPageSpacing property has been decreased by 4 and for iPhone 6 Plus - by 6 values. So, if you'll try to to set pageSpacing property for iPhone 4 or 5 you'll see a white line between pages but on 6 and 6 Plus this line disappears and view of second controller moves to few pixels left.

    For now I just set different values for UIPageViewControllerOptionInterPageSpacingKey while initialize my UIPageViewController:

    - (id)initWithTransitionStyle:(UIPageViewControllerTransitionStyle)style navigationOrientation:(UIPageViewControllerNavigationOrientation)navigationOrientation options:(NSDictionary *)options
    {
        NSMutableDictionary *dictionary = [NSMutableDictionary new];
        NSNumber *pageSpacing =
        IS_IPHONE_4_OR_LESS
        ? @(0)
        : IS_IPHONE_5
        ? @(0)
        : IS_IPHONE_6
        ? @(4)
        : @(6);
    
        [dictionary setValue:pageSpacing forKey:UIPageViewControllerOptionInterPageSpacingKey];
    
        self = [super initWithTransitionStyle:style navigationOrientation:navigationOrientation options:dictionary];
        return self;
    }
    

    Yes, fix is dirty but I didn't find another way to fix it, especially as it is bug of Apple.