FlexiblePageViewController

UIPageViewController for processing arbitrary data

Introduction

We show data imported from a network or database in a table view through pagination(a.k.a infinite scroll). FlexiblePageViewController is its pager version that extends UIPageViewController.

Installation

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

pod "FlexiblePageViewController"

Description

To handle arbitrary data, FlexiblePageViewController provides FlexiblePageViewDataSource and FlexiblePageViewDelegate protocols.

In FlexiblePageViewDataSource, you should return the number of data to display and the data at a specific index.

func numberOfData(in pageView: FlexiblePageViewController) -> Int {
  return contents.count
}

func flexiblePageView(_ pageView: FlexiblePageViewController, dataAt index: Int) -> Any? {
  guard contents.indices.contains(index) else { return nil }
  return contents[index]
}

In FlexiblePageViewDelegate, you should performs pagination operations.

func flexiblePageView(_ pageView: FlexiblePageViewController, lastIndex index: Int) {
  loadData(at: page)
}

The view controller acting as the "page" to show each item is assigned to the pageInfo as a tuple.

pageContainer.pageInfo = (storyboard: "Main", view: ContentViewController.self)

Usage

MainViewController that act as a pager:

import UIKit
import FlexiblePageViewController

class MainViewController: UIViewController {

  @IBOutlet weak var pageLbl: UILabel!

  var pageContainer: FlexiblePageViewController!
  var contents: [String] = []
  var page = 0
  let contentDataSource = ContentDataSource()

  override func viewDidLoad() {
    super.viewDidLoad()
    loadData(at: page) {
      self.setPager()
    }
  }

  private func setPager() {
    pageContainer = FlexiblePageViewController()
    pageContainer.pageDataSource = self
    pageContainer.pageDelegate = self
    pageContainer.numberOfItemsPerPage = 10
    pageContainer.didPageSelected = didPageSelected
    pageContainer.pageInfo = (storyboard: "Main", view: ContentViewController.self)
    view.addSubview(pageContainer.view)
    view.sendSubview(toBack: pageContainer.view)
  }

  func didPageSelected(index: Int) {
    pageLbl.text = "Page \(index + 1)"
  }

  func loadData(at page: Int, onComplete: (() -> Void)? = nil) {
    contentDataSource.loadData(at: page) {
      self.contents.append(contentsOf: $0)
      self.page += 1
      onComplete?()
    }
  }

}

extension MainViewController: FlexiblePageViewDataSource, FlexiblePageViewDelegate {

  func numberOfData(in pageView: FlexiblePageViewController) -> Int {
    return contents.count
  }

  func flexiblePageView(_ pageView: FlexiblePageViewController, dataAt index: Int) -> Any? {
    guard contents.indices.contains(index) else { return nil }
    return contents[index]
  }

  func flexiblePageView(_ pageView: FlexiblePageViewController, lastIndex index: Int) {
    loadData(at: page)
  }

}

ContentViewController to show each data:

import UIKit
import FlexiblePageViewController

class ContentViewController: UIViewController {

  @IBOutlet weak var contentLbl: UILabel!

  var content: String = ""

  // Need to receive data from pager
  override func set(_ extras: [String : Any]) {
    content = extras["data"] as? String ?? ""
  }

  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    contentLbl.text = content
  }

}

Example

The example project loads and displays 10 pages at first. After passing the page several times, it loads next 10 items. (pagination)

See full example here.

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

APIs

• .pageDataSource: FlexiblePageViewDataSource?

• .pageDelegate: FlexiblePageViewDelegate?

• .numberOfItemsPerPage: Int = 20

  Number of items received in a database or network at a time.

• .didPageSelected: ((Int) -> Void)?

  Function to be executed when the page is selected. Get the current page index as an argument.

• .currentIndex: Int = 0

  Index of page to be shown

• .pageInfo: (storyboard: String, view: UIViewController.Type)

  Storyboard name and identifier of the view controller to show each item

Author

InJung Chung / @mu29

License

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