Disable UIPageViewController bounce

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Searched a lot for this one, but couldn\'t find a proper solution yet.

Is it possible to disable the bounce effect of a UIPageViewController and still

The only working solution, 2020

Below is a complete solution that, unlike with other answers, doesn't require you to write/test your own code for tracking the index of the currently displayed page.

Assuming that your pages are stored in sourcePageViewControllers immutable array and after you've created your UIPageViewController as myPageViewController:

let scrollView = myPageViewController.view.subviews.compactMap({ $0 as? UIScrollView }).first!
scrollView.delegate = <instance of YourScrollViewDelegateClass>

And then:

extension YourScrollViewDelegateClass: UIScrollViewDelegate {

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard sourcePageViewControllers.count > 1 else {
            scrollView.isScrollEnabled = false
            return
        }
        
        guard let viewControllers = myPageViewController.viewControllers, viewControllers.count != 0 else { return }

        let baseRecord =
            viewControllers
            .map { [superview = myPageViewController.view!] viewController -> (viewController: UIViewController, originX: CGFloat) in
                let originX = superview.convert(viewController.view.bounds.origin, from: viewController.view).x
                return (viewController: viewController, originX: originX)
            }
            .sorted(by: { $0.originX < $1.originX })
            .first!

        guard let baseIndex = sourcePageViewControllers.firstIndex(of: baseRecord.viewController) else { return }
        let baseViewControllerOffsetXRatio = -baseRecord.originX/scrollView.bounds.width

        let progress = (CGFloat(baseIndex) + baseViewControllerOffsetXRatio)/CGFloat(sourcePageViewControllers.count - 1)
        if !(0...1 ~= progress) {
            scrollView.isScrollEnabled = false
            scrollView.isScrollEnabled = true
        }
    }

}

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渐次进展

2020-11-27 04:43

Edited answer of Dong Ma, where:

added - respects layout direction (Hebrew for example)
fixed - wrong counting currentIndex when swipes very quick

Info:

Written in Swift 5.0
Builded and tested in Xcode 10.2.1
iOS 12.0

How to:

Let's assume we have a UIViewController where UIPageViewController is added as child VC.

class ViewController: UIViewController {
    var pageNavigationController: UIPageViewController! 

    private var lastPosition: CGFloat
    private var nextIndex: Int
    var currentIndex: Int     

    // rest of UI's setups  
}

Set ViewController as delegate of UIPageViewController:

extension ViewController: UIPageViewControllerDataSource {

    func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
        guard
            let currentVisibleViewController = pageViewController.viewControllers?.first,
            let nextIndex = pageViewControllers.firstIndex(of: currentVisibleViewController)
        else {
            return
        }

        self.nextIndex = nextIndex
    }

    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
        if completed, let currentVisibleViewController = pageViewController.viewControllers?.first, let newIndex = pageViewControllers.firstIndex(of: currentVisibleViewController) {
            self.currentIndex = newIndex
        }

        self.nextIndex = self.currentIndex
    }
}

Set ViewController as datasource of UIPageController:

extension ViewController: UIPageViewControllerDataSource {

    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        // provide next VC
    }

    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        // provide prev VC
    }

    // IMPORTANT: that's the key why it works, don't forget to add it
    func presentationIndex(for pageViewController: UIPageViewController) -> Int {
        return currentIndex
    }
}

"Disable" bouncing by setting ViewController as delegate of UIPageViewController's UIScrollView:

// MARK: - UIScrollViewDelegate (disable bouncing for UIPageViewController)
extension BasePaginationVC: UIScrollViewDelegate {

    func attachScrollViewDelegate() {
        for subview in pageNavigationController.view.subviews {
            if let scrollView = subview as? UIScrollView {
                scrollView.delegate = self
                lastPosition = scrollView.contentOffset.x
                break
            }
        }
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        switch UIView.userInterfaceLayoutDirection(for: view.semanticContentAttribute) {
        case .leftToRight:
            if nextIndex > currentIndex {
                if scrollView.contentOffset.x < (lastPosition - (0.9 * scrollView.bounds.size.width)) {
                    currentIndex = nextIndex
                }
            } else {
                if scrollView.contentOffset.x > (lastPosition + (0.9 * scrollView.bounds.size.width)) {
                    currentIndex = nextIndex
                }
            }

            if currentIndex == 0 && scrollView.contentOffset.x < scrollView.bounds.size.width {
                scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0)
            } else if currentIndex == pageViewControllers.count - 1 && scrollView.contentOffset.x > scrollView.bounds.size.width {
                scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0)
            }
        case .rightToLeft:
            if nextIndex > currentIndex {
                if scrollView.contentOffset.x > (lastPosition + (0.9 * scrollView.bounds.size.width)) {
                    currentIndex = nextIndex
                }
            } else {
                if scrollView.contentOffset.x < (lastPosition - (0.9 * scrollView.bounds.size.width)) {
                    currentIndex = nextIndex
                }
            }

            if currentIndex == pageViewControllers.count - 1 && scrollView.contentOffset.x < scrollView.bounds.size.width {
                scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0)
            } else if currentIndex == 0 && scrollView.contentOffset.x > scrollView.bounds.size.width {
                scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0)
            }
        @unknown default:
            fatalError("unknown default")
        }

        lastPosition = scrollView.contentOffset.x
    }

    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
        switch UIView.userInterfaceLayoutDirection(for: view.semanticContentAttribute) {
        case .leftToRight:
            if currentIndex == 0 && scrollView.contentOffset.x <= scrollView.bounds.size.width {
                targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0)
            } else if currentIndex == pageViewControllers.count - 1 && scrollView.contentOffset.x >= scrollView.bounds.size.width {
                targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0)
            }
        case .rightToLeft:
            if currentIndex == pageViewControllers.count - 1 && scrollView.contentOffset.x <= scrollView.bounds.size.width {
                targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0)
            } else if currentIndex == 0 && scrollView.contentOffset.x >= scrollView.bounds.size.width {
                targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0)
            }
        @unknown default:
            fatalError("unknown default")
        }
    }
}

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日久生厌

2020-11-27 04:44

UIPageViewController doesn't actually do much for you. You can use a UIScrollView with view controllers quite easily, and disable the bounce on that.

Just do something like

int x=0;
for (NSString *storyboardID in storyboardIDs){
        UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:storyboardID];
        [self addChildViewController:vc];
        vc.view.frame = CGRectMake(x++*vc.view.frame.size.width, 0, vc.view.frame.size.width, vc.view.frame.size.height);
        [self.scrollView addSubview:vc.view];
        [vc didMoveToParentViewController:self];
        self.scrollView.contentSize = CGSizeMake(storyboardIDs.count*vc.view.frame.size.width, vc.view.frame.size.height);
}

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刺人心

2020-11-27 04:44

@Dong Ma's approach is perfect but it can be a little bit improved and simplified.

Code to put into viewDidLoad:

for subview in view.subviews {
    if let scrollView = subview as? UIScrollView {
        scrollView.delegate = self
        break
    }
}

Implementation for scrollViewDidScroll:

public func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if (currentPage == 0 && scrollView.contentOffset.x < scrollView.bounds.size.width) || (currentPage == totalNumberOfPages - 1 && scrollView.contentOffset.x > scrollView.bounds.size.width) {
      scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0)
    }
  }

Implementation for scrollViewWillEndDragging:

public func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    if (currentPage == 0 && scrollView.contentOffset.x <= scrollView.bounds.size.width) || (currentPage == totalNumberOfPages - 1 && scrollView.contentOffset.x >= scrollView.bounds.size.width) {
      targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0)
    }
  }

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终归单人心

2020-11-27 04:45

I wasn't sure how to correctly manage the currentIndex but ended up doing

extension Main: UIPageViewControllerDelegate {
    func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
        if completed {
            guard let viewController = pageViewController.viewControllers?.first,
                index = viewControllerDatasource.indexOf(viewController) else {
                fatalError("Can't prevent bounce if there's not an index")
            }
            currentIndex = index
        }
    }
}

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感动是毒

2020-11-27 04:51

My solution in Swift 5
In my scenario, I first load the UIPageViewController on the second page. And I have a total of three pages so I open on the middle one.

Here's the code of my UIPageViewController

import UIKit

class MainPageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate, UIScrollViewDelegate {

  let idList = ["OverviewController", "ImportantItemsController", "ListMenuController"] // A list of all of my viewControllers' storyboard id
  var currentPage = 1 // Tracking the current page

  override func viewDidLoad() {
    super.viewDidLoad()
    setupPageController()

    for subview in self.view.subviews { // Getting the scrollView
      if let scrollView = subview as? UIScrollView {
        scrollView.delegate = self
        break;
      }
    }
  }

  // UIPageViewControllerDataSource
  func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
    let index = idList.firstIndex(of: viewController.restorationIdentifier!)!
    if (index > 0) {
      return storyboard?.instantiateViewController(withIdentifier: idList[index - 1])
    }
    return nil
  }

  func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    let index = idList.firstIndex(of: viewController.restorationIdentifier!)!
    if (index < idList.count - 1) {
      return storyboard?.instantiateViewController(withIdentifier: idList[index + 1])
    }
    return nil
  }

  func presentationCount(for pageViewController: UIPageViewController) -> Int {
    return idList.count
  }

  // UIPageViewControllerDelegate
  func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    if completed {
      guard let vc = pageViewController.viewControllers?.first else { return }
      switch vc {
      case is ImportantItemsController:
          currentPage = 1
      case is OverviewController:
          currentPage = 0
      default:
          currentPage = 2
      }
    }
  }

  // ScrollViewDelegate
  func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let totalViewControllersInPageController = idList.count
    if (currentPage == 0 && scrollView.contentOffset.x < scrollView.bounds.size.width) {
      scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0);
    } else if (currentPage == totalViewControllersInPageController - 1 && scrollView.contentOffset.x > scrollView.bounds.size.width) {
      scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0);
    }
  }

  func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    let totalViewControllersInPageController = idList.count
    if (currentPage == 0 && scrollView.contentOffset.x <= scrollView.bounds.size.width) {
      targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0);
    } else if (currentPage == totalViewControllersInPageController - 1 && scrollView.contentOffset.x >= scrollView.bounds.size.width) {
      targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0);
    }
  }

  fileprivate func setupPageController() {
    let controller = storyboard?.instantiateViewController(withIdentifier: idList[1]) as! ImportantItemsController // Loading on the second viewController
    setViewControllers([controller], direction: .forward, animated: true, completion: nil)
    dataSource = self
    delegate = self
  }
}

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