I'm trying to add a series of UINavigationControllers to a single UIPageViewController as if adding swipe nav between pages. I did this with some success with standard view controllers, but I'm now trying to add nav controllers instead. Here's my Storyboard:
What I'd like to do is instantiate swipe nav (like Snapchat) between all pages in the 3rd row. Since they all lead to other view controllers, each is embedded within it's own nav controller. Here's my code:
class ViewController: UIViewController, UIPageViewControllerDataSource { // <-- Error here
// Sets up UIPageViewController. Must add to array count and instantiate new VCs.
var myNavControllers = Array(count: 3, repeatedValue:UINavigationController())
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
let pvc = segue.destinationViewController as! UIPageViewController
pvc.dataSource = self // <-- Error here
let storyboard = UIStoryboard(name: "Main", bundle: nil);
var vc0 = storyboard.instantiateViewControllerWithIdentifier("Nav1") as! UINavigationController
var vc1 = storyboard.instantiateViewControllerWithIdentifier("Nav2") as! UINavigationController
var vc2 = storyboard.instantiateViewControllerWithIdentifier("Nav3") as! UINavigationController
var vc3 = storyboard.instantiateViewControllerWithIdentifier("Nav4") as! UINavigationController
self.myNavControllers = [vc0, vc1, vc2, vc3]
pvc.setViewControllers([myNavControllers[1]], direction:.Forward, animated:true, completion:nil)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UINavigationController) -> UINavigationController? {
var currentIndex = find(self.myNavControllers, viewController)!+1
if currentIndex >= self.myNavControllers.count {
return nil
}
return self.myNavControllers[currentIndex]
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UINavigationController) -> UINavigationController? {
var currentIndex = find(self.myNavControllers, viewController)!-1
if currentIndex < 0 {
return nil
}
return self.myNavControllers[currentIndex]
}
}
Problem is, I'm getting two errors. One at class: ViewController declaration: Type 'ViewController' does not conform to protocol 'UIPageViewControllerDataSource'. The other at pvc.dataSource = self, with error: Cannot assign a value of type 'ViewController' to a value of type 'UIPageViewControllerDataSource?'
Can what I'm trying to do be accomplished? If so, do I need to alter my code somewhere or achieve this an entirely different way?
The protocol you have defined is in ViewController but that should be defined in UIPageViewController class.
class PageViewController: UIPageViewController, UIPageViewControllerDataSource {
}
For this, you need to create a new class which should be associated with Page View Controller that you have taken on storyboard.
Related
I'm basically trying to create a custom UITabBarController since I need some specific functionality. The TabBar itself is done and working, but I don't quite know how to display ViewControllers in this CustomTabBarViewController itself.
Assuming i have the following method:
func tabSelected(_ index: Int) {}
and knowing the height of my TabBar through tabbar.frame.size, how do I instantiate two ViewControllers above the TabBar and switch between them when the tabSelected method is called? A transition animation would be even nicer, but not really necessary.
NOTE: my TabBar doesn't inherit from UITabBarController, only from the regular UIViewController, to avoid further confusion.
Here I created sample project:
CustomTabBarViewController
You should have container view for child ViewControllers
Then you should have array with embed ViewControllers
You should call method in
CustomTabBarViewController which change ViewController inside
container view to ViewController from array of VCs at index which you pass as parameter of this method
Start with declaring outlet collection for your TabBar buttons and also get reference for container view where your ViewControllers will be showed
#IBOutlet var tabBarButtons: [UIButton]!
#IBOutlet weak var container: UIView!
then create array for your tab bar items
var items: [UIViewController]?
next create lazy variables for your controllers
private lazy var aVC: A = {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
return storyboard.instantiateViewController(withIdentifier: "a") as! A
}()
private lazy var bVC: B = {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
return storyboard.instantiateViewController(withIdentifier: "b") as! B
}()
.... this can be simplified by creating method which returns ViewController depending on VC’s identifier
After that append ViewControllers to your items array and also each add as child of your TabBarViewController
override func viewDidLoad() {
super.viewDidLoad()
items = [aVC, bVC]
items!.forEach { addChild($0) }
}
continue with declaring method for setting ViewController
private func setViewController(_ viewController: UIViewController) {
items!.forEach { $0.view.removeFromSuperview(); $0.willMove(toParent: nil) }
container.addSubview(viewController.view)
viewController.view.frame = container.bounds
viewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
viewController.didMove(toParent: self)
}
now add action for your tab bar buttons and get index of button. Then with this index call your tabSelected method
#IBAction func buttonPressed(_ sender: UIButton) {
if let index = tabBarButtons.index(of: sender) {
tabSelected(index)
}
}
inside tabSelected set VC from items depending on index of sender tab bar button
func tabSelected(_ index: Int) {
if let item = items?[index] {
setViewController(item)
}
}
finally in viewDidLoad set first item
override func viewDidLoad() {
...
tabSelected(0)
}
Now you can fully customize your ViewController and make other epic stuff which you know from UITabBarController
Here's another approach:
1. In your CustomTabBarViewController define an array to hold the ViewControllers:
var viewControllers: [UIViewController]
Instantiate the view controllers and add them to the array:
// If you're not using storyboard:
let homeViewController = HomeViewController()
// If using storyboard:
let searchViewController = storyboard.instantiateViewController(withIdentifier: "SearchViewController")
viewControllers = [homeViewController, searchViewController, ...]
2. Define a variable to keep track of the tab button that is selected:
var selectedIndex: Int = 0
3. Implement your tabSelected method like so. I've explained each line in code:
func tabSelected(_ index: Int) {
let previousIndex = selectedIndex
selectedIndex = index
// Use previousIndex to access the previous ViewController from the viewControllers array.
let previousVC = viewControllers[previousIndex]
// Remove the previous ViewController
previousVC.willMove(toParentViewController: nil)
previousVC.view.removeFromSuperview()
previousVC.removeFromParentViewController()
// Use the selectedIndex to access the current ViewController from the viewControllers array.
let vc = viewControllers[selectedIndex]
// Add the new ViewController (Calls the viewWillAppear method of the ViewController you are adding)
addChildViewController(vc)
vc.view.frame = contentView.bounds
// contentView is the main view above your tab buttons
contentView.addSubview(vc.view)
// Call the viewDidAppear method of the ViewController you are adding using didMove(toParentViewController: self)
vc.didMove(toParentViewController: self)
}
What I have
I have a ViewController (TutorialViewController) and a UIPageViewController (TutorialPageViewController). There are also 3 extra views on the storyboard with StoryBoard ID's:
GreenViewController
BlueViewController
RedViewController
I have been following this tutorial (Kudos to the author, very well written).
On the Green View Controller I have defined a variable:
var passedVariable = ""
And in the ViewDidLoad I print it out.
Here are the two controllers that have the code:
UIViewController (TutorialViewController):
class TutorialViewController: UIViewController {
#IBOutlet weak var pageControl: UIPageControl!
#IBOutlet weak var containerView: UIView!
var tutorialPageViewController: TutorialPageViewController? {
didSet {
tutorialPageViewController?.tutorialDelegate = self
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let tutorialPageViewController = segue.destinationViewController as? TutorialPageViewController {
self.tutorialPageViewController = tutorialPageViewController
}
}
#IBAction func didTapNextButton(sender: UIButton) {
tutorialPageViewController?.scrollToNextViewController()
}
}
extension TutorialViewController: TutorialPageViewControllerDelegate {
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageCount count: Int) {
pageControl.numberOfPages = count
}
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageIndex index: Int) {
pageControl.currentPage = index
}
}
UIPageViewController
class TutorialPageViewController: UIPageViewController {
weak var tutorialDelegate: TutorialPageViewControllerDelegate?
//let vc0 = GreenViewController(nibName: "GreenViewController", bundle: nil)
private(set) lazy var orderedViewControllers: [UIViewController] = {
// The view controllers will be shown in this order
return [self.newColoredViewController("Green"),
self.newColoredViewController("Red"),
self.newColoredViewController("Blue"), self.newColoredViewController("Pink")]
}()
override func viewDidLoad() {
super.viewDidLoad()
//self.vc0.passedVariable = "Passed Data"
dataSource = self
delegate = self
if let initialViewController = orderedViewControllers.first {
scrollToViewController(initialViewController)
}
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageCount: orderedViewControllers.count)
}
/**
Scrolls to the next view controller.
*/
func scrollToNextViewController() {
if let visibleViewController = viewControllers?.first,
let nextViewController = pageViewController(self,
viewControllerAfterViewController: visibleViewController) {
scrollToViewController(nextViewController)
}
}
private func newColoredViewController(color: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("\(color)ViewController")
}
/**
Scrolls to the given 'viewController' page.
- parameter viewController: the view controller to show.
*/
private func scrollToViewController(viewController: UIViewController) {
setViewControllers([viewController],
direction: .Forward,
animated: true,
completion: { (finished) -> Void in
// Setting the view controller programmatically does not fire
// any delegate methods, so we have to manually notify the
// 'tutorialDelegate' of the new index.
self.notifyTutorialDelegateOfNewIndex()
})
}
/**
Notifies '_tutorialDelegate' that the current page index was updated.
*/
private func notifyTutorialDelegateOfNewIndex() {
if let firstViewController = viewControllers?.first,
let index = orderedViewControllers.indexOf(firstViewController) {
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageIndex: index)
}
}
}
// MARK: UIPageViewControllerDataSource
extension TutorialPageViewController: UIPageViewControllerDataSource {
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
// User is on the first view controller and swiped left to loop to
// the last view controller.
guard previousIndex >= 0 else {
return orderedViewControllers.last
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count
// User is on the last view controller and swiped right to loop to
// the first view controller.
guard orderedViewControllersCount != nextIndex else {
return orderedViewControllers.first
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
extension TutorialPageViewController: UIPageViewControllerDelegate {
func pageViewController(pageViewController: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers: [UIViewController],
transitionCompleted completed: Bool) {
notifyTutorialDelegateOfNewIndex()
}
}
protocol TutorialPageViewControllerDelegate: class {
/**
Called when the number of pages is updated.
- parameter tutorialPageViewController: the TutorialPageViewController instance
- parameter count: the total number of pages.
*/
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageCount count: Int)
/**
Called when the current index is updated.
- parameter tutorialPageViewController: the TutorialPageViewController instance
- parameter index: the index of the currently visible page.
*/
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageIndex index: Int)
}
What I have tried
I have tried declaring the View Controller first like so:
let vc0 = GreenViewController(nibName: "GreenViewController", bundle: nil)
And then passing the data like so:
override func viewDidLoad() {
vc0.passedVariable = "This was passed, Dance with Joy"
}
Nothing is printing out in the console.
I also tried changing the bundle above to:
bundle: NSBundle.mainBundle()
Still nada
Question
I plan to load data on the TutorialViewController from an alamofire request, I want to pass that data to one of the ViewControllers (green, blue, red)
How do I pass data that has been acquired from the TutorialViewController to one of the child views that will load?
First, I want to thank you for checking out my tutorial and all of the nice things you said about it.
Second, I have a solution for you! I went ahead and committed the solution to the GitHub repo I linked in the tutorial. I will also post the code here.
(1) Create a UIViewController subclass to add custom properties to. For this example, I chose to add a UILabel since it's the easiest to view when running the app.
class ColoredViewController: UIViewController {
#IBOutlet weak var label: UILabel!
}
(2) Inside Main.storyboard, change the custom class for each UIViewController "page" to ColoredViewController in the Identity Inspector.
(3) Add a UILabel to each "page" and constraint it however you'd like. I chose to vertically and horizontally center it in the container. Don't forget to link the UILabel to ColoredViewController's #IBOutlet weak var label: UILabel!.
(4) Optional: I deleted the default "Label" text in each one that way if we never set the label's text in code, we will not show "Label" to the user.
(5) We need to do some TLC to TutorialPageViewController so it knows that orderedViewControllers is now a ColoredViewController array. To make things easy, I'm just going to paste the entire class:
class TutorialPageViewController: UIPageViewController {
weak var tutorialDelegate: TutorialPageViewControllerDelegate?
private(set) lazy var orderedViewControllers: [ColoredViewController] = {
// The view controllers will be shown in this order
return [self.newColoredViewController("Green"),
self.newColoredViewController("Red"),
self.newColoredViewController("Blue")]
}()
override func viewDidLoad() {
super.viewDidLoad()
dataSource = self
delegate = self
if let initialViewController = orderedViewControllers.first {
scrollToViewController(initialViewController)
}
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageCount: orderedViewControllers.count)
}
/**
Scrolls to the next view controller.
*/
func scrollToNextViewController() {
if let visibleViewController = viewControllers?.first,
let nextViewController = pageViewController(self,
viewControllerAfterViewController: visibleViewController) {
scrollToViewController(nextViewController)
}
}
private func newColoredViewController(color: String) -> ColoredViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("\(color)ViewController") as! ColoredViewController
}
/**
Scrolls to the given 'viewController' page.
- parameter viewController: the view controller to show.
*/
private func scrollToViewController(viewController: UIViewController) {
setViewControllers([viewController],
direction: .Forward,
animated: true,
completion: { (finished) -> Void in
// Setting the view controller programmatically does not fire
// any delegate methods, so we have to manually notify the
// 'tutorialDelegate' of the new index.
self.notifyTutorialDelegateOfNewIndex()
})
}
/**
Notifies '_tutorialDelegate' that the current page index was updated.
*/
private func notifyTutorialDelegateOfNewIndex() {
if let firstViewController = viewControllers?.first as? ColoredViewController,
let index = orderedViewControllers.indexOf(firstViewController) {
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageIndex: index)
}
}
}
// MARK: UIPageViewControllerDataSource
extension TutorialPageViewController: UIPageViewControllerDataSource {
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let coloredViewController = viewController as? ColoredViewController,
let viewControllerIndex = orderedViewControllers.indexOf(coloredViewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
// User is on the first view controller and swiped left to loop to
// the last view controller.
guard previousIndex >= 0 else {
return orderedViewControllers.last
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let coloredViewController = viewController as? ColoredViewController,
let viewControllerIndex = orderedViewControllers.indexOf(coloredViewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count
// User is on the last view controller and swiped right to loop to
// the first view controller.
guard orderedViewControllersCount != nextIndex else {
return orderedViewControllers.first
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
extension TutorialPageViewController: UIPageViewControllerDelegate {
func pageViewController(pageViewController: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers: [UIViewController],
transitionCompleted completed: Bool) {
notifyTutorialDelegateOfNewIndex()
}
}
protocol TutorialPageViewControllerDelegate: class {
/**
Called when the number of pages is updated.
- parameter tutorialPageViewController: the TutorialPageViewController instance
- parameter count: the total number of pages.
*/
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageCount count: Int)
/**
Called when the current index is updated.
- parameter tutorialPageViewController: the TutorialPageViewController instance
- parameter index: the index of the currently visible page.
*/
func tutorialPageViewController(tutorialPageViewController: TutorialPageViewController,
didUpdatePageIndex index: Int)
}
(6) Inside TutorialViewController: let's set the label.text. I chose to use viewDidLoad, but feel free to stuff this logic inside a network request completion block.
override func viewDidLoad() {
super.viewDidLoad()
if let greenColoredViewController = tutorialPageViewController?.orderedViewControllers.first {
greenColoredViewController.label.text = "Hello world!"
}
}
Hope this helps!
Obviously, according the comments, there's still confusion how this can be solved.
I'll try to introduce one approach and explain way this might make sense. Note though, that there are a few other viable approaches which can solve this problem.
The root view controller
First we take a look at the "root" controller which is an instance of TutorialViewController. This one is responsible to fetch/get/obtain/retrieve a "model". The model is and instance of pure data. It must be appropriate to define and initialise the page view controllers. Since we have a number of pages, it makes sense this model is some kind of array or list of some kind of objects.
For this example, I use an array of strings - just in order to illustrate how this can be implemented. A real example would obtain an array of likely more complex objects, where each of it will be rendered in its own page. Possibly, the array has been fetched from a remote resource with a network request.
In this example, the strings happen to be the "colour" of the page view controllers. We create an appropriate property for class TutorialViewController:
class TutorialViewController: UIViewController {
#IBOutlet weak var pageControl: UIPageControl!
#IBOutlet weak var containerView: UIView!
private let model = ["Red", "Green", "Blue"]
...
Note that the property has private access: nobody else than the class itself should fiddle around with it.
Passing the Model from the Root Controller to its Embedded View Controller
The embedded view controller is an instance of TutorialPageViewController.
The root view controller passes the model to the embedded view controller in the method prepareForSegue. The embedded view controller must have an appropriate property which is suitable for its view of the model.
Note: A model may have several aspects or views. The model which has been initialised by the root view controller may not be appropriate to be passed as is to any of its presented view controllers. Thus, the root view controller may first filter, copy, reorder, or transform its model in order to make it suitable for the presented view controller.
Here, in this example, we take the model as is:
In class TutorialViewController:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let tutorialPageViewController = segue.destinationViewController as? TutorialPageViewController {
self.tutorialPageViewController = tutorialPageViewController
self.tutorialPageViewController!.model = self.model
}
}
Note that the TutorialViewController has itself a property (here model) which is set by the presenting view controller.
Here, the model is an array of strings. It should be obvious that the number of elements in the array should later become the number of pages in the page view controller. It should also be clear that each element is rendered on the corresponding page in a content view controller. Thus, we can say an element in the array serves as the "model" for each page.
We need to provide the property model in the TutorialPageViewController:
class TutorialPageViewController: UIPageViewController {
internal var model: [String]?
Note that the access is either public or internal, so that any presenting view controller can set it.
Passing the Model from the TutorialViewController to each Content View Controller
A page view controller (TutorialViewController) is responsible to create an array of content view controllers whose view render the page.
An easy approach to create the array of view controllers utilising a lazy property is shown below:
class TutorialPageViewController: UIPageViewController {
internal var model: [String]?
private(set) lazy var orderedViewControllers: [UIViewController] = {
// The view controllers will be shown in this order
assert(self.model != nil)
return self.model!.map {
self.newColoredViewController($0)
}
}()
The important part is here:
return self.model!.map {
self.newColoredViewController($0)
}
Here, we create N view controllers passing it the model (a String) in its factory function.
map returns an array of view controllers - suitable for the page view controller.
Once this has been implemented, the example works as in its original form.
You might now change the "factory" function which creates a view controller given a string as argument. For example you might set a label:
private func newColoredViewController(color: String) -> UIViewController {
let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("MyContentViewController") as! MyContentViewController
vc.label = color
return vc
}
Here, again label is the "model" of the view controller. It's totally up the view controller how label will be rendered - if at all.
Based on some of the comments, I can see that there is one small snippet missing from #Jeff's answer that could help clarify how to actually transfer data from the TutorialPageViewController to the ColoredViewController. He likely assumed that this part of the answer was inferred. This can, however be frustrating if you don't know what to do from here.
With that being said, I'm going to piggy back off of his answer. Let's say, for example, that we want to change the text of the label inside the ColoredViewController from the TutorialPageViewController. We will set the text value to the background color of that particular view controller.
1) Start by defining the variable inside the ColoredViewController class and setting the label text to that value.
class ColoredViewController: UIViewController {
#IBOutlet weak var label: UILabel!
var labelText: String?
override func viewDidLoad() {
super.viewDidLoad()
if let text = labelText {
label.text = text
}
// Do any additional setup after loading the view.
}
}
2) Set the value of labelText in the newColoredViewController method that we already created inside the TutorialPageViewController class
private func newColoredViewController(color: String) -> ColoredViewController {
let newController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "\(color)ViewController") as! ColoredViewController
newController.labelText = label
return newController
}
The previously empty label inside the view controller will now display the color value.
Note: You don't necessarily have to have 3 separate view controllers for this example to apply to your particular application. You could have 1 view controller that is serving as a template for each page within the page view controller. In this case, you would not reference the new view controller in the newColoredViewController method with a variable value but instead with the static name of the one content view controller you want to use.
Using the following code, I have a series of view controllers embedded in a page view controller that I'm swiping through. I just can't find a way to segue to another view controller via a bar button press. I'm planning on writing a separate function for each bar button icon in each view controller.
class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
private var pages: [UIViewController]!
override func viewDidLoad() {
super.viewDidLoad()
self.dataSource = self
self.delegate = self
self.pages = [
self.storyboard!.instantiateViewControllerWithIdentifier("FirstNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("SecondNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("ThirdNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("FourthNav") as! UINavigationController
]
let startingViewController = self.pages.first! as UIViewController
self.setViewControllers([startingViewController], direction: .Forward, animated: false, completion: nil)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
// if currently displaying last view controller, return nil to indicate that there is no next view controller
return (index == self.pages.count - 1 ? nil : self.pages[index + 1])
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
// if currently displaying first view controller, return nil to indicate that there is no previous view controller
return (index == 0 ? nil : self.pages[index - 1])
}
}
Change your implementation of PageViewController to the following (I made some changes in the methods you already implemented, and I added a new instance method.)
class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
private var pages: [UINavigationController]!
private var currentPageIndex: Int!
override func viewDidLoad() {
super.viewDidLoad()
self.dataSource = self
self.delegate = self
self.pages = [
self.storyboard!.instantiateViewControllerWithIdentifier("FirstNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("SecondNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("ThirdNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("FourthNav") as! UINavigationController
]
(self.pages[0].topViewController as! FirstViewController).parentPageViewController = self
(self.pages[1].topViewController as! SecondViewController).parentPageViewController = self
(self.pages[2].topViewController as! ThirdViewController).parentPageViewController = self
(self.pages[3].topViewController as! FourthViewController).parentPageViewController = self
self.currentPageIndex = 0
let startingViewController = self.pages.first! as UINavigationController
self.setViewControllers([startingViewController], direction: .Forward, animated: false, completion: nil)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
self.currentPageIndex = index
// if currently displaying last view controller, return nil to indicate that there is no next view controller
return (self.currentPageIndex == self.pages.count - 1 ? nil : self.pages[self.currentPageIndex + 1])
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
self.currentPageIndex = index
// if currently displaying first view controller, return nil to indicate that there is no previous view controller
return (index == 0 ? nil : self.pages[index - 1])
}
func displayPageForIndex(index: Int, animated: Bool = true) {
assert(index >= 0 && index < self.pages.count, "Error: Attempting to display a page for an out of bounds index")
// nop if index == self.currentPageIndex
if self.currentPageIndex == index { return }
if index < self.currentPageIndex {
self.setViewControllers([self.pages[index]], direction: .Reverse, animated: true, completion: nil)
} else if index > self.currentPageIndex {
self.setViewControllers([self.pages[index]], direction: .Forward, animated: true, completion: nil)
}
self.currentPageIndex = index
}
}
Now, in each of your child view controllers, add two pieces of code:
A property that maintains a weak reference to the parent PageViewController instance.
weak var parentPageViewController: PageViewController!
An IBAction to which you connect each of your bar button items. You may need to change the body of this method depending on how your Storyboard is set up.
#IBAction func barButtonTapped(sender: UIBarButtonItem) {
var newIndex = -1
switch sender.title! {
case "First":
newIndex = 0
case "Second":
newIndex = 1
case "Third":
newIndex = 2
case "Fourth":
newIndex = 3
default: break
}
self.parentPageViewController.displayPageForIndex(newIndex)
}
Does each controller need to be embedded in a UINavigationController? You could just have a UINavigationController embed a single UIViewController, that view controller references a pageviewcontroller and a barButtonItem, when the barButtonItem is tapped trigger an action that tells the pageviewcontroller to change indexes.
Or if you want to go with your current plan of action which is a barButtonItem in each UINavigationController, write a protocol with a delegate method didSelectBarButtonAtIndex or something, then give each UINavigationController a delegate property, have the pageviewcontroller conform to the protocol and become the delegate for each nav controller. Then when a bar button is tapped, call the delegate method, which should make the page controller change it's index.
Courtesy of Using UIPageViewController with swift and multiple view controllers, I'm embedding navigation controllers in a UIPageViewController so I can horizontally scroll thru them (like swipe nav). Problem:
When I reach the first or last nav controller, and then swipe in the opposite direction, the 2nd-to-first/last nav controller will duplicate. So I'll have 5 nav controllers. For example:
Starting at FirstNav, swipe left all the way to FourthNav. When I swipe right through the array of controllers from FourthNav, the sequence will be: ThirdNav, ThirdNav, SecondNav, FirstNav. Can anyone find out what's going on?
class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
var index = 0
var identifiers: NSArray = ["FirstNav", "SecondNav", "ThirdNav", "FourthNav"]
override func viewDidLoad() {
super.viewDidLoad()
self.dataSource = self
self.delegate = self
let startingViewController = self.viewControllerAtIndex(self.index)
let viewControllers: NSArray = [startingViewController]
self.setViewControllers(viewControllers as [AnyObject], direction: UIPageViewControllerNavigationDirection.Forward, animated: false, completion: nil)
}
func viewControllerAtIndex(index: Int) -> UINavigationController! {
if index == 0 {
return self.storyboard!.instantiateViewControllerWithIdentifier("FirstNav") as! UINavigationController
}
if index == 1 {
return self.storyboard!.instantiateViewControllerWithIdentifier("SecondNav") as! UINavigationController
}
if index == 2 {
return self.storyboard!.instantiateViewControllerWithIdentifier("ThirdNav") as! UINavigationController
}
if index == 3 {
return self.storyboard!.instantiateViewControllerWithIdentifier("FourthNav") as! UINavigationController
}
return nil
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let identifier = viewController.restorationIdentifier
let index = self.identifiers.indexOfObject(identifier!)
//if the index is the end of the array, return nil since we dont want a view controller after the last one
if index == identifiers.count - 1 {
return nil
}
//increment the index to get the viewController after the current index
self.index = self.index + 1
return self.viewControllerAtIndex(self.index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let identifier = viewController.restorationIdentifier
let index = self.identifiers.indexOfObject(identifier!)
//if the index is 0, return nil since we dont want a view controller before the first one
if index == 0 {
return nil
}
//decrement the index to get the viewController before the current one
self.index = self.index - 1
return self.viewControllerAtIndex(self.index)
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return 0
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return 0
}
}
The issue has to do with your calculation of the index variable in your pageViewController(_:viewControllerBeforeViewController:) and pageViewController(_:viewControllerAfterViewController:) methods. To simplify that logic and the overall logic of your page view controller, you should change your implementation to the following:
class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
private var pages: [UIViewController]!
override func viewDidLoad() {
super.viewDidLoad()
self.dataSource = self
self.delegate = self
self.pages = [
self.storyboard!.instantiateViewControllerWithIdentifier("FirstNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("SecondNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("ThirdNav") as! UINavigationController,
self.storyboard!.instantiateViewControllerWithIdentifier("FourthNav") as! UINavigationController
]
let startingViewController = self.pages.first! as UIViewController
self.setViewControllers([startingViewController], direction: .Forward, animated: false, completion: nil)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
// if currently displaying last view controller, return nil to indicate that there is no next view controller
return (index == self.pages.count - 1 ? nil : self.pages[index + 1])
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let index = (self.pages as NSArray).indexOfObject(viewController)
// if currently displaying first view controller, return nil to indicate that there is no previous view controller
return (index == 0 ? nil : self.pages[index - 1])
}
}
You don't even need to maintain an index instance variable, and this implementation does not do so. But you could, if you wanted. This solution also instantiates a single instance of each UINavigationController instead of instantiating a new one every time the user attempts to scroll to a different page, which conserves memory and preserves the state of the view controllers as the user scrolls between them.
Please excuse the non-descriptive pages variable name. I didn't want to create a conflict with UIPageViewController's viewControllers property.
I have two view controllers with an id of firstController and secondController. I want to be able to slide between them using a page controller but I don't know how to do this. I have looked at tutorials but they are for making little tutorial bits at the start of your apps not the actual app.
So how would I link them up so that I can swipe between them?
Here is the code wich you need. I also searched very long to find this. It works very fine. Maybe you want to change "as?" to "as!" to force a downcast of the destination ViewControllers, but don't do it if you are planning a segue later.
import UIKit
class ViewController: UIViewController, UIPageViewControllerDataSource {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
var myViewControllers = Array(count: 4, repeatedValue:UIViewController())
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
let pvc = segue.destinationViewController as? UIPageViewController
pvc?.dataSource = self
let storyboard = UIStoryboard(name: "Main", bundle: nil);
var vc0 = storyboard.instantiateViewControllerWithIdentifier("Infoseite") as! UIViewController
var vc1 = storyboard.instantiateViewControllerWithIdentifier("Anmeldung2") as! UIViewController
var vc2 = storyboard.instantiateViewControllerWithIdentifier("Anmeldung3") as! UIViewController
var vc3 = storyboard.instantiateViewControllerWithIdentifier("Anmeldung4") as! UIViewController
storyboard.instantiateViewControllerWithIdentifier("Anmeldung4")
self.myViewControllers = [ vc0, vc1, vc2, vc3]
pvc?.setViewControllers([myViewControllers[1]], direction:.Forward, animated:false, completion:nil)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
var currentIndex = find(self.myViewControllers, viewController)!+1
if currentIndex >= self.myViewControllers.count {
return nil
}
return self.myViewControllers[currentIndex]
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
var currentIndex = find(self.myViewControllers, viewController)!-1
if currentIndex < 0 {
return nil
}
return self.myViewControllers[currentIndex]
}
You can simply delete vc3 and vc4. You only have to watch out that every vc3 and vc4 is deleted and that you write "Array(count: 2,"...
Use a gesture recognizer to see when the user has swiped a direction...
Won't let me post images, so take a look here.
Then change the view controller using something like this...
let secondViewController = self.storyboard.instantiateViewControllerWithIdentifier("SecondViewController") as SecondViewController
self.navigationController.pushViewController(secondViewController, animated: true)
You could also use a segue of course. (performSegueWithIdentifier method)