使用UIPageViewController创建首次进入应用的欢迎走马灯页

UIPageViewControlle

主视图

  • 主视图是指应用的内容主界面

  • 添加viewDidAppear(_:animated)中通过withIdentifier实例化视图容器

  • 通过present(UIViewController:animated:completion)显示视图

import UIKit

class ViewController: UIViewController {
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        if UserDefaults.standard.bool(forKey: "hasViewedWalkthrough") {
            return
        }
        
        if let pageViewController = storyboard?.instantiateViewController(withIdentifier: "WalkthroughController") as? WalkthroughPageViewController {
            present(pageViewController, animated: true, completion: nil)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

滑动视图

容器视图

  • 创建自定义的类继承UIPageViewController并,实现UIPageViewControllerDataSource协议

    • 定义每个视图显示的内容数组

    • 实现UIPageViewControllerDataSource协议的两个方法当用户导航切换页面是都会被调用
      指定和返回一个显示上一个或是下一个指定的content view controller

      • pageViewController(_:viewControllerBefore:)

      • pageViewController(_:viewControllerAfter:)

    • 在viewDidLoad中将dataSource设置为self

    • 在view中调用setViewControllers方法,在参数中设置要显示的内容视图

    • 定义一个辅助方法用于返回内容视图

      • 避免数组索引越界

      • 通过storyboard?.instantiateViewController(withIdentifier:)实例化一个视图,并设置相关的视图内容,如UILabel等。

      • 返回内容视图

  • 创建Page的指示器的两种方式

    • 默认的指示器

      • 需要实现UIPageViewControllerDataSource协议的两个可选方法

        • presentationCount(for:)返回页面总数

        • presentationIndex(for:)返回当前选中的页面指示器索引

    • 自定义的指示器

      • 从组件库中拖拽出一个 Page controller组件到视图,并放到合适的位置添加好约束

      • 在内容视图类定义一个@IBOutlet var pagecontrol连接到视图中的Page Control组件,并设置总数和当前所在的索引

      • 在viewDidLoad中赋值 pageControl.currentPage = index

import UIKit

class WalkthroughPageViewController: UIPageViewController, UIPageViewControllerDataSource {
    
    var pageHeadings = ["Personalize", "Locate", "Discover"]
    var pageImages = ["foodpin-intro-1", "foodpin-intro-2", "foodpin-intro-3"]
    var pageContent = ["Pin your favorite restaurants and create your own food guide", "Search and locate your favourite restaurant on Maps", "Find restaurants pinned by your friends and other foodies around the world"]

    override func viewDidLoad() {
        super.viewDidLoad()
        
        dataSource = self
        
        if let startingViewController = contentViewController(at: 0) {
            setViewControllers([startingViewController], direction: .forward, animated: true, completion: nil)
        } else {
            print("nil")
        }

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        var index = (viewController as! WalkthroughContentViewController).index
        index -= 1
        return contentViewController(at: index)
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        var index = (viewController as! WalkthroughContentViewController).index
        index += 1
        return contentViewController(at: index)
    }
    
    func contentViewController(at index: Int) -> WalkthroughContentViewController? {
        
        if index < 0 || index >= pageHeadings.count {
            return nil
        }
        
        if let pageContentViewController = storyboard?.instantiateViewController(withIdentifier: "WalkthroughContentViewController") as? WalkthroughContentViewController {
            
            pageContentViewController.heading = pageHeadings[index]
            pageContentViewController.content = pageContent[index]
            pageContentViewController.imageFile = pageImages[index]
            pageContentViewController.index = index
            
            return pageContentViewController
        }
        
        return nil
    }
    
    func forward(index: Int) {
        if let nextViewController = contentViewController(at: index + 1) {
            setViewControllers([nextViewController], direction: .forward, animated: true, completion: nil)
        }
        
        
    }

}

内容视图

  • 是一个可重用的视图,继承正常的UIViewController

  • 在这里定义视图上的内容,如UILabel、UIImageView、或其它视图组件

  • 也可以定义一些对视图的操作方法

import UIKit

class WalkthroughPageViewController: UIPageViewController, UIPageViewControllerDataSource {
    
    var pageHeadings = ["Personalize", "Locate", "Discover"]
    var pageImages = ["foodpin-intro-1", "foodpin-intro-2", "foodpin-intro-3"]
    var pageContent = ["Pin your favorite restaurants and create your own food guide", "Search and locate your favourite restaurant on Maps", "Find restaurants pinned by your friends and other foodies around the world"]

    override func viewDidLoad() {
        super.viewDidLoad()
        
        dataSource = self
        
        if let startingViewController = contentViewController(at: 0) {
            setViewControllers([startingViewController], direction: .forward, animated: true, completion: nil)
        } else {
            print("nil")
        }

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        var index = (viewController as! WalkthroughContentViewController).index
        index -= 1
        return contentViewController(at: index)
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        var index = (viewController as! WalkthroughContentViewController).index
        index += 1
        return contentViewController(at: index)
    }
    
    func contentViewController(at index: Int) -> WalkthroughContentViewController? {
        
        if index < 0 || index >= pageHeadings.count {
            return nil
        }
        
        if let pageContentViewController = storyboard?.instantiateViewController(withIdentifier: "WalkthroughContentViewController") as? WalkthroughContentViewController {
            
            pageContentViewController.heading = pageHeadings[index]
            pageContentViewController.content = pageContent[index]
            pageContentViewController.imageFile = pageImages[index]
            pageContentViewController.index = index
            
            return pageContentViewController
        }
        
        return nil
    }
    
    func forward(index: Int) {
        if let nextViewController = contentViewController(at: index + 1) {
            setViewControllers([nextViewController], direction: .forward, animated: true, completion: nil)
        }
        
        
    }

}

页面只在应用最初进入的时候显示一次的功能

  • 使用UserDefaults类来存储是否显示过的状态

  • 在最后一个内容界面按下“进入界面”后的位置使用UserDefaults.standard.set(Bool:key:)方法设置保存状态

  • 在主页面的viewDidAppear(animated:)中检测状态

这里放出代码地址: https://github.com/dengxife/SwiftTips

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