A ViewPager with NavigationBar component based on UIPageViewController and UICollectionView
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README.md

BMO ViewPager

CI Status Version License Platform

⚠️ The latest version for Swift 3.2 is 3.2.0 ⚠️ (Not Maintained)

⚠️ The latest version for Swift 4.0 is 4.1.3 ⚠️

⚠️ The latest version for Swift 4.2 is 4.2.1 ⚠️

4.1.0 Migrating to 4.2.0

Syntax renaming : NSAttributedStringKey to NSAttributedString.Key

3.2.0 to 4.1.0 Migration

Fix error spelling : interporation to interpolation, if you have access this variable, please change the naming

About

A ViewPager with NavigationBar component based on UIPageViewController and UICollectionView, which is a convenience way to supply and manager each viewController.

I want to make UIPageViewController more intuitive for using it, like UITableView, and supply a navigationBar quickly and simply.

More importantly, when UIPageViewController scroll continuously, pageControl sometimes will get wrong index, this viewPager can help you solve it.

There are some standard dataSource and delegate implemented for generating each page and navigationBar, each of these classes have simple sample code showing in the Pod Example for BmoViewPager.

Simple Usage

Create a UIView extend BmoViewPager

Implement BmoViewPagerDataSource

give page count and each page controller, just like using tableView

func bmoViewPagerDataSourceNumberOfPage(in viewPager: BmoViewPager) -> Int {
    return YourPageCount
}
func bmoViewPagerDataSource(_ viewPager: BmoViewPager, viewControllerForPageAt page: Int) -> UIViewController {
    return YourPageViewController
}

With a NavigationBar

Create a UIView extend BmoViewPagerNavigationBar

Assign a BmoViewPager to the BmoViewPagerNavigationBar

using default style, only need to give the each page title

func bmoViewPagerDataSourceNaviagtionBarItemTitle(_ viewPager: BmoViewPager, navigationBar: BmoViewPagerNavigationBar, forPageListAt page: Int) -> String? {
    return YourPageTitleString
}

navigation item title can custom attributed

func bmoViewPagerDataSourceNaviagtionBarItemNormalAttributed(_ viewPager: BmoViewPager, navigationBar: BmoViewPagerNavigationBar, forPageListAt page: Int) -> [NSAttributedString.Key : Any]? {
    return [
        NSAttributedString.Key.foregroundColor : UIColor.lightGray,
        NSAttributedString.Key.font : UIFont.systemFont(ofSize: 14.0)
    ]
}
func bmoViewPagerDataSourceNaviagtionBarItemHighlightedAttributed(_ viewPager: BmoViewPager, navigationBar: BmoViewPagerNavigationBar, forPageListAt page: Int) -> [NSAttributedString.Key : Any]? {
    return [
        NSAttributedString.Key.foregroundColor : UIColor.red,
        NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 14.0)
    ]
}

if you don't want use default style, you can custom your own background view and highlighted background view

Advanced Usage

Support Right-to-Left (RTL) User Interface

Support Vertical and Horizontal direction scroll

BmoNavigationBar Auto Focus (Default is true)

BmoNavigationBar Title can set normal and highlighted attributed style

BmoViewPager infinitScroll (Default is false)

BmoViewPager presentedPageIndex can programmatically assign the present page

Custom NavigationBar animation, you can get scroll progress from BmoViewPagerDelegate

Navigation bar interpolation animation when change viewPager page by tap navigationItem

InfiniteScroll Custom NavigationBar animation

PageControl Optimized

native pageController have a default pageControl if you implement the func presentationCount(for pageViewController: UIPageViewController) -> Int and func presentationIndex(for pageViewController: UIPageViewController) -> Int but sometimes the index have a little bug, if you feel the way too, hope it help you

Native PageController continuously scroll continuously scroll using bmoViewPager

Popular Issue

How to animate changing pages on BmoViewPager ?

There is a property isInterpolationAnimated in BmoViewPager and BmoViewPagerNavigationBar, default value both true. Most importantly, If you want to have scroll animation every time, the pageViewController need be initialed before BmoViewPagerDataSource ask it. and told BmoViewPager the reference by public func setReferencePageViewController(_ vc: UIViewController, at page: Int)

For example, I always keep the UIViewController of previous page, current page and next page in a dictionary cachedPageViewControllers

var cachedPageViewControllers = [Int: UIViewController]()
func bmoViewPagerDelegate(_ viewPager: BmoViewPager, didAppear viewController: UIViewController, page: Int) {
    switch page {
    case 0:
        self.prepareCachedPageViewControllers(pages: [pageCount - 1, page, page + 1])
    case 1..<(pageCount - 1):
        self.prepareCachedPageViewControllers(pages: [page - 1, page, page + 1])
    case pageCount - 1:
        self.prepareCachedPageViewControllers(pages: [page - 1, page, 0])
    default:
        break
    }
}
func bmoViewPagerDataSource(_ viewPager: BmoViewPager, viewControllerForPageAt page: Int) -> UIViewController {
    if let cacheVC = cachedPageViewControllers[page] {
        return cacheVC
    } else {
        let vc = createPageViewController(page)
        viewPager.setReferencePageViewController(vc, at: page)
        cachedPageViewControllers[page] = vc
        return vc
    }
}
private func prepareCachedPageViewControllers(pages: [Int]) {
    cachedPageViewControllers.forEach({ (key, vc) in
        if !pages.contains(key) {
            cachedPageViewControllers[key] = nil
        }
    })
    pages.forEach { (page) in
        if cachedPageViewController[page] == nil {
            let vc = createPageViewController(page)
            viewPager.setReferencePageViewController(vc, at: page)
            cachedPageViewControllers[page] = vc
        }
    }
}
private func createPageViewController(_ page: Int) -> UIViewController {
    //TODO: return your own UIViewController
}

Be sure to return different UIViewController for every page

Because BmoViewPager is based on UIPageViewController, and when the scroll view scroll to edge, it will ask UIPageViewControllerDataSource to get the next and the previous page. At the same time, BmoViewPager save the view controller and page number in the view controller's view, it will let the this page view controller has wrong property.

Example

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

Requirements

  • iOS 8.0+
  • Xcode 8.0+
  • Swift 3.0+

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:

$ gem install cocoapods

CocoaPods 1.1.0+ is required to build BmoViewPager 4.0.0+.

To integrate BmoViewPager into your Xcode project using CocoaPods, specify it in your Podfile:

use_frameworks!

target '<Your Target Name>' do
    pod 'BmoViewPager', '~> 4.0.0'
end

Then, run the following command:

$ pod install

Manually

If you prefer not to use the dependency managers, you can integrate BmoViewPager into your project manually, just copy the BmoViewPager folder into your project.

Author

LEE ZHE YU, tzef8220@gmail.com

License

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