Add UIViewController as subview of UIScrollView - ios

Question

I am building an app with some scrolling inside. In short, this is my configuration:
1) class_1: a view with a set of elements inside (something similar to camera row) listed by using a collection view
2) class_2: a modal view called by class_1 where I show each singular element selected (from class_1). Inside the same class I have also implemented the horizontal scroll of all the elements
3) class_3: a simple viewcontroller with an imageview inside which will contain the element I will show in class_2
Running my app looks like class_3 is not added as subview of class_2 and all the singular content I try to load are not visible.
Below is my class_2 code
Interface:
#import <UIKit/UIKit.h>
#import "class_3.h"
#interface class_2 : UIViewController
#property (strong, nonatomic) IBOutlet UIPageControl *pageControl;
#property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
#property (weak, nonatomic) NSArray *imageList;
#end
Implementation:
#interface class_2 () {
NSMutableArray *_viewControllers;
}
- (void)loadScrollViewWithImage:(NSUInteger)indexImage;
#end
#implementation class_2
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// _imageList is passed from class_1 when I call class_2. Contains an array of images
self.pageControl.numberOfPages = [_imageList count];
self.pageControl.currentPage = 0;
// I store inside an array N objects as the number f images I have to show. At the beginning the array has only null objects, then it will contains the views based on the images I have scrolled.
//I am storying my images inside a view because maybe I will show more controls and not just the image. It will be much easier manage them.
_viewControllers = [[NSMutableArray alloc] init];
for (NSUInteger i = 0; i < [_imageList count]; i++) {
[_viewControllers addObject:[NSNull null]];
}
// I set some properties of my scrollview defined as outlet
self.scrollView.frame = CGRectMake(0, 0, 320, 345);
self.scrollView.contentSize = CGSizeMake(CGRectGetWidth(self.scrollView.frame) * [_imageList count], CGRectGetHeight(self.scrollView.frame));
self.scrollView.pagingEnabled = YES;
// this is set to NO, I switched to YES just now for debug (at least I can see how big the area is since there are no images visible)
self.scrollView.showsHorizontalScrollIndicator = YES;
self.scrollView.showsVerticalScrollIndicator = NO;
self.scrollView.scrollsToTop = NO;
self.scrollView.delegate = self;
// for testing now I always take the first and second elements of my array. I load both so when I move from the first image to the second is already there and there is no gap/flashing effect
[self loadScrollViewWithImage:0];
[self loadScrollViewWithImage:1];
}
#pragma mark - Private methods
- (void)loadScrollViewWithImage:(NSUInteger)indexImage {
// I scrolled until the last image, from here I can only go back
if (indexImage >= [_imageList count])
return;
// I replace the placeholder (null) object
class_3 *controller = [_viewControllers objectAtIndex:indexImage];
if ((NSNull *)controller == [NSNull null]) {
controller = [[class_3 alloc] init];
[_viewControllers replaceObjectAtIndex:indexImage withObject:controller];
}
// I add the controller's view to the scroll view - in case this is the first time I'm scrolling this image
if (controller.view.superview == nil) {
// I set my controller frame as the scrollview works as container
CGRect frame = self.scrollView.frame;
frame.origin.x = CGRectGetWidth(frame) * indexImage;
frame.origin.y = 0;
controller.view.frame = frame;
// I finally add my viewcontroller as child of my superview and subview of the scrollview
[self addChildViewController:controller];
[self.scrollView addSubview:controller.view];
[controller didMoveToParentViewController:self];
// I set an image corrisponding with the element selected from class_1
controller.imageView.image = [_imageList objectAtIndex:indexImage]
// I also tried with a fake image...just in case. No one of them is visible
//controller.imageView.image = [UIImage imageNamed:#"tempPhoto"];
}
}
My class_3 is a viewcontroller which hosts only an image view shoulb be populated with the corresponding image selezted before.
The pagecontroller is used to show where I scrolling (letf/right) and how many elements there are. The scrolling is phisically managed with the scrollview.
Here is my class_3 definition
Interface:
#import <UIKit/UIKit.h>
#import "class_3.h"
#interface class_3 : UIViewController
#property (strong, nonatomic) IBOutlet UIImageView *imageView;
#end
Implementation (nothing really impressive)
#import "class_3.h"
#interface class_3 ()
#end
#implementation class_3
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.imageView.image = [UIImage imageNamed:#"tempPhoto"];
}
#end
What am I missing?
Tnx

Answer 1

Your class_3 should be a UIView, instead of a UIViewController, subclass. See here