IOS How to access uipageviewcontroller from its children?

Question

I have the below classes, the first contains an instance of UIPageViewController and the second is the view controller of the childs

@interface GuidePager : UIViewController     <UIPageViewControllerDataSource, UIPageViewControllerDelegate>
@property (strong, nonatomic) UIPageViewController *pageController;
@property NSArray *viewControllers;
- (void)flipToPage:(NSString *)index;

@end

AND

@interface GuidePagerChild : UIViewController <UIWebViewDelegate>

@end

I need to call flipToPage of the GuidePager from GuidePagerChild where GuidePagerChild.

Please help.

Answer 1

Add a delegate protocol for the child:

@protocol GuidePagerChildDelegate;

@interface GuidePagerChild : UIViewController <UIWebViewDelegate>
@property (nonatomic, weak) id<GuidePagerChildDelegate> delegate;   
@end

@protocol GuidePagerChildDelegate <NSObject>
@required
- (void)guidePagerChild:(GuidePagerChild *)child flipToPage:(NSString *)index
@end

Then:

@interface GuidePager : UIViewController <
    GuidePagerChildDelegate,  // Add the new protocol to the list.
    UIPageViewControllerDataSource, 
    UIPageViewControllerDelegate
>
@property (strong, nonatomic) UIPageViewController *pageController;
@property NSArray *viewControllers;
- (void)flipToPage:(NSString *)index;

@end

Then when you create the child:

GuidePagerChildDelegate *child = [[GuidePagerChild alloc] init];  // Or however you create it.
child.delegate = self;  // Assuming you create it from within GuidePager.  If not, get a pointer to GuidePager and set it as the delegate.

Then:

@implementation GuidePager

...

- (void)guidePagerChild:(GuidePagerChild *)child flipToPage:(NSString *)index 
{
     [self flipToPage:index];
}

...

@end