libr-ios/librx/PageViewController.swift

//
//  PageViewController.swift
//  librx
//
//  Created by Yunlong Zheng on 11/26/15.
//  Copyright © 2015 librx. All rights reserved.
//

import UIKit

class PageViewController: UIPageViewController ,UIPageViewControllerDataSource{

    var pageHeadings = ["遇见", "发现", "价值"]
    
    var pageImages = ["Thinking", "FireElement", "StarHalfEmpty"]
    
    var pageSubHeadings = ["师，三人行必有我师",
        "热度决定高度",
        "不只是旁观，证明自己"]
 
    override func viewDidLoad() {
        super.viewDidLoad()
        // Set the data source to itself
        dataSource = self
        // Create the first walkthrough screen
        if let startingViewController = self.viewControllerAtIndex(0) {
            setViewControllers([startingViewController], direction: .Forward, animated: true,
        completion: nil)
        }
    }
    
    func pageViewController(pageViewController: UIPageViewController,
            viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
            var index = (viewController as! PageContentViewController).index
            index++
            return self.viewControllerAtIndex(index)
    }
    
    func pageViewController(pageViewController: UIPageViewController,
        viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
        var index = (viewController as! PageContentViewController).index
        index--
        return self.viewControllerAtIndex(index)
    }

    
    func viewControllerAtIndex(index: Int) -> PageContentViewController? {
        if index == NSNotFound || index < 0 || index >= self.pageHeadings.count {
            return nil
        }
        // Create a new view controller and pass suitable data.
        if let pageContentViewController =
            storyboard?.instantiateViewControllerWithIdentifier("PageContentViewController") as?
            PageContentViewController {
            pageContentViewController.imageFile = pageImages[index]
            pageContentViewController.heading = pageHeadings[index]
            pageContentViewController.subHeading = pageSubHeadings[index]
            pageContentViewController.index = index
            return pageContentViewController
            }
        return nil
    }
    
    func forward(index: Int) {
        if let nextViewController = self.viewControllerAtIndex(index + 1) {
        setViewControllers([nextViewController], direction: .Forward, animated: true,
        completion: nil)
        }
    }
    
}