EMPageViewController is a full replacement for UIPageViewController with the features and predictability you’ve always wanted from a page view controller.
EMPageViewController gives your delegate messages for every step of the page transition process: before, during, and after. This makes it very easy for you to incorporate animations or any other events that are highly dependent on the progress of transitioning a page.
In addition to the ability scroll to any view controller, you can also easily scroll to the next or previous page without gestures if your app has navigation buttons.
EMPageViewController is not a subclass of UIPageViewController. Instead, it's a subclass of UIViewController with a UIScrollView, written in Swift, and it has common sense delegate and data source methods that will make the development of your page-based iOS app a breeze.
- Xcode 6.1+
- iOS 7+
- iPhone, iPad, and iPod Touch
Simply include EMPageViewController.swift into your project.
Learn how to use EMPageViewController in your project by cloning this repository and opening the Xcode project file Greetings.xcodeproj in Examples/Greetings. The code for initializing EMPageViewController and implementing its delegate and data source is located in RootViewController.swift.
EMPageViewController allows for page navigation through different view controllers, or "pages". View controllers can be navigated via swiping gestures, or called programmatically.
Properties for providing view controllers and receiving messages during navigation.
The object that provides view controllers on an as-needed basis throughout the navigation of the page view controller. If the data source is nil, gesture based scrolling will be disabled and all view controllers must be provided through selectViewController:direction:animated:completion:.
Declaration
weak var dataSource:EMPageViewControllerDataSource!The object that receives messages throughout the navigation of the page view controller.
Declaration
weak var delegate:EMPageViewControllerDelegate?Methods for initializing and navigating the page view controller.
Sets the view controller that will be selected after the animation. This method is also used to provide the first view controller that will be selected in the page view controller. If a data source has been set, the view controllers to the left and/or right of the selected view controller will also be loaded but not appear yet.
Declaration
func selectViewController(viewController: UIViewController, direction: EMPageViewControllerNavigationDirection, animated: Bool, completion: ((transitionSuccessful: Bool) -> Void)?)| Parameter | Description |
|---|---|
selectViewController |
The view controller to be selected |
direction |
The direction of the navigation and animation if applicable |
animated |
A Boolean whether or not to animate the transition |
completion |
A block that's called after the transition is finished. The block parameter transitionSuccessful is true if the transition to the selected view controller was completed successfully. |
Transitions to the view controller right of the currently selected view controller. Also described as going to the next page.
Declaration
func scrollForwardAnimated(animated: Bool, completion: ((transitionSuccessful: Bool) -> Void)?)| Parameter | Description |
|---|---|
animated |
A Boolean whether or not to animate the transition |
completion |
A block that's called after the transition is finished. The block parameter transitionSuccessful is true if the transition to the selected view controller was completed successfully. If false, the transition returned to the view controller it started from. |
Transitions to the view controller left of the currently selected view controller. Also described as going to the previous page.
Declaration
func scrollReverseAnimated(animated: Bool, completion: ((transitionSuccessful: Bool) -> Void)?)| Parameter | Description |
|---|---|
animated |
A Boolean whether or not to animate the transition |
completion |
A block that's called after the transition is finished. The block parameter transitionSuccessful is true if the transition to the selected view controller was completed successfully. If false, the transition returned to the view controller it started from. |
The EMPageViewControllerDataSource protocol is adopted to provide the view controllers that are displayed when the user scrolls through pages. Methods are called on an as-needed basis.
Each method returns a UIViewController object or nil if there are no view controllers to be displayed.
If the data source is nil, gesture based scrolling will be disabled and all view controllers must be provided through selectViewController:direction:animated:completion:.
Called to optionally return a view controller that is to the left of a given view controller.
Declaration
func em_pageViewController(pageViewController: EMPageViewController, viewControllerLeftOfViewController viewController: UIViewController) -> UIViewController?Parameters
| Parameter | Description |
|---|---|
pageViewController |
The page view controller |
viewController |
The point of reference view controller |
Return value
The view controller that is to the left of the given viewController, or nil if there is no view controller to be displayed.
Called to optionally return a view controller that is to the right of a given view controller.
Declaration
func em_pageViewController(pageViewController: EMPageViewController, viewControllerRightOfViewController viewController: UIViewController) -> UIViewController?Parameters
| Parameter | Description |
|---|---|
pageViewController |
The page view controller |
viewController |
The point of reference view controller |
Return value
The view controller that is to the right of the given viewController, or nil if there is no view controller to be displayed.
The EMPageViewControllerDelegate protocol is adopted to receive messages for all major events of the page transition process.
Called before scrolling to a new view controller.
This method will not be called if the start view controller is nil. A common scenario where this will occur is when you initialize the page view controller and use selectViewController:direction:animated:completion: to load the first controller.
Declaration
optional func em_pageViewController(pageViewController: EMPageViewController, willStartScrollingFrom startViewController: UIViewController, destinationViewController: UIViewController)Parameters
| Parameter | Description |
|---|---|
pageViewController |
The page view controller |
startViewController |
The currently selected view controller the transition is starting from |
destinationViewController |
The view controller being scrolled to where the transition will end |
Note If bouncing is enabled, it is possible this method will be called more than once for one page transition. It can be called before the initial scroll to the destination view controller (which is when it is usually called), and it can also be called when the scroll momentum carries over slightly to the view controller after the original destination view controller.
Called whenever there has been a scroll position change in a page transition. This method is very useful if you need to know the exact progress of the page transition animation.
This method will not be called if the start view controller is nil. A common scenario where this will occur is when you initialize the page view controller and use selectViewController:direction:animated:completion: to load the first controller.
Declaration
optional func em_pageViewController(pageViewController: EMPageViewController, isScrollingFrom startViewController: UIViewController, destinationViewController: UIViewController, progress: CGFloat)Parameters
| Parameter | Description |
|---|---|
pageViewController |
The page view controller |
startViewController |
The currently selected view controller the transition is starting from |
destinationViewController |
The view controller being scrolled to where the transition will end |
progress |
The progress of the transition, where 0 is a neutral scroll position, >= 1 is a complete transition to the right view controller, and <= -1 is a complete transition to the left view controller. Values may be greater than 1 or less than -1 if the scroll velocity is quick enough. |
Called after a page transition attempt has completed.
Declaration
optional func em_pageViewController(pageViewController: EMPageViewController, didFinishScrollingFrom startViewController: UIViewController?, destinationViewController: UIViewController, transitionSuccessful: Bool)Parameters
| Parameter | Description |
|---|---|
pageViewController |
The page view controller |
startViewController |
The currently selected view controller the transition is starting from |
destinationViewController |
The view controller that was been attempted to be selected |
transitionSuccessful |
A Boolean whether the transition to the destination view controller was successful or not. If true, the new selected view controller is destinationViewController. If false, the transition returned to the view controller it started from, so the selected view controller is startViewController. |
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Copyright (c) 2015 Erik Malyak
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