Using View Controller from storyboard programmatically in a Page View Controller - ios

Question

I have an app with a storyboard. I am using several View Controller with segues to choose from a table view depending on the item selected. I want to have a page view controller in which the pages will be one or more view controller from the storyboard, even repeating them. I am trying to init the Page View Controller like this:
....
self.dataSource=self;
UIViewController *initialViewController =[self viewControllerAtIndex:current];
NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];
[self setViewControllers:viewControllers direction:UIPageViewControllerNavigationOrientationHorizontal animated:NO completion:nil];
....
- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
if ((descriptions.count == 0) ||
(index >= descriptions.count)) {
return nil;
}
current=index;
// Create a new view controller and pass suitable data.
NSString *language = [[NSLocale preferredLanguages] objectAtIndex:0];
Description *description=[DBCompany getDescriptionById:language descriptionId:[[descriptions objectAtIndex:index] integerValue]];
UIViewController *viewController=nil;
if(description.frame==100){
viewController=[[Company100ViewController alloc] init];
((Company100ViewController*)viewController).companyId = companyId;
}
return viewController;
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
if ((descriptions.count == 0) ||
(current-1 < 0)) {
return nil;
}
return [self viewControllerAtIndex:current-1];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
if ((descriptions.count == 0) ||
(current >= descriptions.count)) {
return nil;
}
return [self viewControllerAtIndex:current+1];
}
However the viewcontroller appears in black. I think is because I am adding the UIviewcontroller class but not connecting it to any view, XIB, in my case with the storyboard.
How can I use the different view controller from the storyboard programmatically to use in a page view controller?

Answer 1

If you do viewController=[[Company100ViewController alloc] init] then yes this not a controller that is associated to a storyboard or an XIB. To load the controller with an XIB you have to do the following:
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
Company100ViewController * vc = (Company100ViewController *)[sb instantiateViewControllerWithIdentifier:#"vc-identifier"];
In the storyboard make sure you set the view controller's id to vc-identifier; whatever identifier you choose.

Answer 2

Swift 3
let sb = UIStoryboard(name: "MainStoryboard", bundle: nil)
let vc = sb.instantiateViewController(withIdentifier: "vc-identifier")

Answer 3

Swift
In case you want to init from a UIViewController object.
guard let vc = storyboard?.instantiateViewController(withIdentifier: "nameVC") else {
return
}
// add to current view
view.addSubview(vc.view)