YTPageController

YTPageController introduces a neat and general solution to perform smooth transitions when scrolling between view controllers, like what Apple did in their Music app:

YTPageController can act as a drop-in replacement of UIPageViewController in your next app, and you no longer need listening to the contentOffset changes and changing the tint colors or frames your self.

Introduction

YTPageController provides a property named pageCoordinator, which is similar to transitionCoordinator in UIViewController, for you to perform your own animations during the page transtion.

For example, to animate a UISegmentedControl, you can simply add these lines your YTPageControllerDelegate:

// Called before a transition starts
- (void)pageController:(YTPageController *)pageController willStartTransition:(id<YTPageTransitionContext>)context {
    // Add your own animations using `pageCoordinator`
    [pageController.pageCoordinator animateAlongsidePagingInView:self.segmentedControl animation:^(id<YTPageTransitionContext>  _Nonnull context) {
        // Update your segmented control according to the context object.
        self.segmentedControl.userInteractionEnabled = NO;
        self.segmentedControl.selectedSegmentIndex = [context toIndex];
    } completion:^(id<YTPageTransitionContext>  _Nonnull context) {
        if ([context isCanceled]) {
            // If transition canceled, restore to the previous state
            self.segmentedControl.selectedSegmentIndex = [context fromIndex];
        }
        self.segmentedControl.userInteractionEnabled = YES;
    }];
}

YTPageController works perfectly with UIKit or third party UI controls, such as AKASegmentedControl:

BetterSegmentedControl:

or any view that can be animated:

Refer to the example project for detailed information.

Basic usage

You have two ways to quickly setup YTPageController:

In code

You can use YTPageController as a child view controller or just by subclassing it. In either way, you must provide your view controllers by setting the dataSource property:

pageController.dataSource = /* your data source object */

...or viewControllers property:

pageController.viewControllers = /* an array of child view controllers */

If you set both properties, dataSource will take the priority.

Using storyboard

You can also set up YTPageController in storyboard without any code, like what you did before with UITabBarController:

Since Apple hasn't provided a custom relationship segue, you need to follow these steps to simulate it:

1. Drag a custom segue from YTPageController to one of your child view controllers and change its class to YTPageControllerSegue;
2. Name the identifier of this segue with the format YTPage_{index}, such as YTPage_0, YTPage_1, YTPage_2, ...

YTPageController will find and perform all these segues in runtime to add the connected view controllers to its child view controllers.

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

iOS 8.0 or above. May be working from iOS 6.0, but I haven't tested it.

Installation

YTPageController is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "YTPageController"

Author

Yeatse CC, iyeatse@gmail.com

License

YTPageController is available under the MIT license. See the LICENSE file for more info.