Delete Image from UIPageViewController - swift

Question

I have a PageViewController set up so that I can add photos from camera or library and the pageviewcontroller resets itself every time the imagepickercontroller is called so the pageviewcontrol updates and shows. It works perfectly (i think). What i know want to do is have the option to delete one of the photos then call the same reset.
The problem is, i can not get an accurate index value of the current image being displayed in the pageviewcontroller. I try to grab the index from the viewControllerBeforeViewController or AfterViewController or the pagecontrolleratindex... but the index does not follow correctly the way the pagecontrol is designed. I read about willtransitiontoviewcontrollers and didfinsihanimating, but those are not being called, i am thinking because i am getting the images from an array and not new view controllers.
My method to delete works, but the index is not accurate so even though the second image is shown the first image could be the one deleted.
Is there a good way to get the current displayed array index so i can delete the image from array? //this array holds images from imagepicker, i call the restartviewcontrollers evertime there is an imagepicked to update the number of pages and this works.
UPDATE
var pageViewController:UIPageViewController!
var pageImages: [UIImage]? = [] //this array holds images from imagepicker, i call the restartviewcontrollers evertime there is an imagepicked to update the number of pages and this works.
var deletePageIndex: Int = 0
func pageViewControllerAtIndex(index: Int) -> PhotoContentPageViewController {
if (self.pageImages!.count == 0 || index >= self.pageImages!.count) {
return PhotoContentPageViewController()
}
var vc = self.storyboard?.instantiateViewControllerWithIdentifier("PhotoPageContentStoryBoard") as! PhotoContentPageViewController
vc.imageFileName = pageImages![index] as! UIImage
vc.pageIndex = index
return vc
}
func restartViewController() {
var startVc = self.pageViewControllerAtIndex(0) as PhotoContentPageViewController
var viewControllers = NSArray(object: startVc)
self.pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: .Forward, animated: true, completion: nil)
}
func startViewControllers() {
self.pageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("PhotoPageViewControllerStoryBoard") as! UIPageViewController
self.pageViewController.dataSource = self
pageViewController.delegate = self
var startVc = self.pageViewControllerAtIndex(0) as PhotoContentPageViewController
var viewControllers = NSArray(object: startVc)
self.pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: .Forward, animated: true, completion: nil)
self.pageViewController.view.frame = CGRectMake(0, -10, self.view.frame.size.width, self.view.frame.size.height-30)
self.addChildViewController(self.pageViewController)
self.view.addSubview(self.pageViewController.view)
self.pageViewController.didMoveToParentViewController(self)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
var vc = viewController as! PhotoContentPageViewController
var index = vc.pageIndex as Int
if (index == 0 || index == NSNotFound) {
return nil
}
index--
return self.pageViewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
var vc = viewController as! PhotoContentPageViewController
var index = vc.pageIndex as Int
if (index == NSNotFound) {
return nil
}
index++
if (index == self.pageImages!.count) {
return nil
}
return self.pageViewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, willTransitionToViewControllers pendingViewControllers: [UIViewController]) {
}
func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if (!completed) {
return
}
}
`

Answer 1

If you actually are using a UIPageViewControllerDelegate, you can use willtransitiontoviewcontrollers but that method only works if you set the delegate property of the page view controller to your view controller. That way, you can simply get the index of the current view controller in page view controller and use it for deletion.
myPageViewController.delegate = self
And make sure your view controller implements UIPageViewControllerDelegate
UPDATE
Assuming that you have an array of you view controllers, you could implement your data source like this:
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
if let index = pages.indexOf(viewController)?.advancedBy(1) where index < pages.count {
return pages[index]
}
return nil
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
if let index = pages.indexOf(viewController)?.advancedBy(-1) where index > -1 {
return pages[index]
}
return nil
}