引言

UIScrollView在实际的项目开发中使用的比较多，可以很好展示图片

说下思路，根据APP的版本来决定是否显示新特性界面，如果版本号和当前版本号不同就显示新特性界面，否则直接进入主界面

• 在项目中先创建2个控制器，MainViewController和NewFeatureViewController，定义两个变量放当前的版本号和存储的版本号

  var currontVersonCode : String? = ""
  var lastVersonCode :String? = ""

//kCFBundleVersionKey 是info.plist文件表示版本号的Key
var key = kCFBundleVersionKey as String
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.
        //创建窗口
        self.window = UIWindow(frame :UIScreen.mainScreen().bounds)
        Main = MainViewController()
        NewFeature = NewFeatureViewController()
        
        //去沙盒取版本号
        lastVersonCode = NSUserDefaults.standardUserDefaults().stringForKey(key)
       //加载程序中的info.plist文件
        currontVersonCode = (NSBundle.mainBundle().infoDictionary![key]) as? String
        if lastVersonCode == currontVersonCode{
            UIApplication.sharedApplication().statusBarHidden = false
            self.window?.rootViewController = Main
            
        }else{
            //保存当前版本号
            self.window?.rootViewController = NewFeature
            
            NSUserDefaults.standardUserDefaults().setObject(currontVersonCode as? AnyObject, forKey: key)
            //立即保存
            NSUserDefaults.standardUserDefaults().synchronize()
        }
        return true
    }

• 新特性界面实现

来到我们创建的NewFeatureViewController中,思路是创建一个UIImage设置一个图片为背景，然后创建UIScrollView在UIImageView上，利用for循环将图片一张一张添加到UIScrollView中，第二张图片的X为第一张图片的宽度，这样就不难理解了

import UIKit

let kCount = 4

class NewFeatureViewController: UIViewController,UIScrollViewDelegate{
    
    var Main :MainViewController!
    var imageView :UIImageView!
    var scrollView :UIScrollView!
    override func loadView() {
        imageView = UIImageView()
        imageView.frame = UIScreen.mainScreen().bounds
        print(UIScreen.mainScreen().bounds)
        imageView?.image = UIImage(named: "new_feature_background.png")
        self.view = imageView
        self.imageView.userInteractionEnabled = true
    }
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let viewSize = self.view.bounds
        //创建scrollView
        scrollView = UIScrollView()
        scrollView.delegate = self
        scrollView.frame = self.view.bounds
        print(self.view.bounds.width)
        scrollView.contentSize = CGSizeMake( self.view.bounds.width * CGFloat(kCount), 0)
        scrollView.showsHorizontalScrollIndicator = false
        scrollView.pagingEnabled = true
        for  i in 0..<kCount {
                self.addImageViewAtIndex(i)
        }
        imageView.addSubview(scrollView)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    //添加图片
    func addImageViewAtIndex(Index:Int)
    {
        let viewSize = self.view.bounds.size
        let imageView :UIImageView = UIImageView()
        imageView.frame = CGRectMake(viewSize.width * CGFloat(Index), 0,viewSize.width, viewSize.height)
        imageView.image = UIImage(named: "new_feature_\(Index+1).png")
   
        scrollView.addSubview(imageView)
    }
}

• 添加PageController

定义一个PageController

var pageView : UIPageControl!

把pageController添加到UIScrollView里去

        //创建pageControl
        pageView = UIPageControl()
        pageView.center = CGPointMake(viewSize.width * 0.5, viewSize.height * 0.95)
        pageView.bounds = CGRectMake(0, 0, 100, 0)
        pageView.numberOfPages = kCount
        pageView.currentPageIndicatorTintColor = UIColor.blackColor()
        pageView.pageIndicatorTintColor = UIColor.lightGrayColor()
        imageView.addSubview(pageView)

UIPageControl同步显示

    func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
      
        pageView.currentPage = Int(scrollView.contentOffset.x) / Int(scrollView.frame.size.width)
    }

看下效果图

第一张 拖动时的效果图

• 在UIScrollView上添加按钮

  
  最后一张图

分享按钮普通状态和选中状态分别为不同的图片
立即体验按钮普通状态和按住状态分别为不同的图片

    func addButton()
    {
        let viewSize = self.view.bounds.size
        let loginBtn : UIButton = UIButton()
        let shareBtn : UIButton = UIButton()
        var loginNormalImage :UIImage = UIImage()
        var loginHeigtImage : UIImage = UIImage()
        var shareNormalImage :UIImage = UIImage()
        var shareHeigtImage : UIImage = UIImage()
        loginNormalImage = UIImage(named:"new_feature_finish_button.png" )!
        loginHeigtImage = UIImage(named: "new_feature_finish_button_highlighted.png")!
        shareNormalImage = UIImage(named: "new_feature_share_true")!
        shareHeigtImage = UIImage(named: "new_feature_share_false")!
        
        loginBtn.center = CGPointMake(viewSize.width * 3.5, viewSize.height * 0.85)
        loginBtn.bounds = CGRectMake(0, 0, loginNormalImage.size.width-20, loginNormalImage.size.height)
        loginBtn.setImage(loginNormalImage, forState: UIControlState.Normal)
        loginBtn.setImage(loginHeigtImage, forState: UIControlState.Highlighted)
        loginBtn.addTarget(self, action: Selector("start"), forControlEvents: .TouchUpInside)
        scrollView.addSubview(loginBtn)
        
        shareBtn.center = CGPointMake(viewSize.width * 3.5, viewSize.height * 0.75)
        shareBtn.bounds = CGRectMake(0, 0, shareNormalImage.size.width, shareNormalImage.size.height)
        shareBtn.setImage(shareNormalImage, forState: UIControlState.Normal)
        shareBtn.setImage(shareHeigtImage, forState: UIControlState.Selected)
        shareBtn.addTarget(self, action: Selector("share:"), forControlEvents: .TouchUpInside)
        scrollView.addSubview(shareBtn)
    }

设置完成之后将按钮添加到UIScrollView中，并在添加图片的for循环中设置判断语句，当在第四张图的时候调用addButton方法

 if i == 3{
           self.addButton()
           }

对于分享按钮反复点击切换不同状态，加上下面代码就可以实现了

func share(btn:UIButton) {
        btn.selected = !btn.selected
}

总结

对于UIScrollView使用还是比较简单的，我觉得还可以扩展一下，例如UIScrollView的无限循环，还有淘宝等首页的自动换页。最后希望能给大家带来帮助，一起进步。