import UIKit
 
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
 
    var window: UIWindow?
 
    func application(_ application: UIApplication, didFinishLaunchingWithOptions
        launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        //增加標識，用于判斷是否是第一次啟動應用...
        if (!(UserDefaults.standard.bool(forKey: "everLaunched"))) {
            UserDefaults.standard.set(true, forKey:"everLaunched")
            let guideViewController = GuideViewController()
            self.window!.rootViewController=guideViewController;
            print("guideview launched!")
        }
        return true
    }
 
    func applicationWillResignActive(_ application: UIApplication) {
    }
 
    func applicationDidEnterBackground(_ application: UIApplication) {
    }
 
    func applicationWillEnterForeground(_ application: UIApplication) {
    }
 
    func applicationDidBecomeActive(_ application: UIApplication) {
    }
 
    func applicationWillTerminate(_ application: UIApplication) {
    }
}

import UIKit
 
class GuideViewController:UIViewController,UIScrollViewDelegate
{
    //頁面數量
    var numOfPages = 3
     
    override func viewDidLoad()
    {
        let frame = self.view.bounds
        //scrollView的初始化
        let scrollView = UIScrollView()
        scrollView.frame = self.view.bounds
        scrollView.delegate = self
        //為了能讓內容橫向滾動，設置橫向內容寬度為3個頁面的寬度總和
        scrollView.contentSize = CGSize(width:frame.size.width * CGFloat(numOfPages),
                                        height:frame.size.height)
        print("\(frame.size.width*CGFloat(numOfPages)),\(frame.size.height)")
        scrollView.isPagingEnabled = true
        scrollView.showsHorizontalScrollIndicator = false
        scrollView.showsVerticalScrollIndicator = false
        scrollView.scrollsToTop = false
        for i in 0..<numOfPages{
            let imgfile = "jianjie\(Int(i+1)).png"
            print(imgfile)
            let image = UIImage(named:"\(imgfile)")
            let imgView = UIImageView(image: image)
            imgView.frame = CGRect(x:frame.size.width*CGFloat(i), y:CGFloat(0),
                                   width:frame.size.width, height:frame.size.height)
            scrollView.addSubview(imgView)
        }
        scrollView.contentOffset = CGPoint.zero
        self.view.addSubview(scrollView)
    }
     
    //scrollview滾動的時候就會調用
    func scrollViewDidScroll(_ scrollView: UIScrollView)
    {
        print("scrolled:\(scrollView.contentOffset)")
        let twidth = CGFloat(numOfPages-1) * self.view.bounds.size.width
        //如果在最后一個頁面繼續滑動的話就會跳轉到主頁面
        if(scrollView.contentOffset.x > twidth)
        {
            let mainStoryboard = UIStoryboard(name:"Main", bundle:nil)
            let viewController = mainStoryboard.instantiateInitialViewController()
            self.present(viewController!, animated: true, completion:nil)
        }
    }
}