今天想要實作 scrollView
記得先準備一張解析度大於1920 * 1080 的照片 (named:”image.jpg”)

1. 建立一個 single view 並且取名 “exScrollView”
2. 先為 ViewController 建立三個屬性

class ViewController: UIViewController {
    
    var myScrollView : UIScrollView!
    var fullSize : CGSize!
    var myImageView : UIImageView!

3. 新增一個 imgeView 且 將剛剛的 image 載入

//get the screen size
        fullSize = UIScreen.main.bounds.size
//add a image form file
        myImageView = UIImageView(image: UIImage(named: "image.jpg")) 

4. 建立一個 ScrollView並且設定初始位置、大小、OffSet位置

myScrollView = UIScrollView()
myScrollView.contentSize = myImageView.bounds.size
myScrollView.backgroundColor = UIColor.black
myScrollView.frame = CGRect(x: 0, y: 0, width: fullSize.width, height: fullSize.height)
myScrollView.contentOffset = CGPoint(x:(myImageView.center.x - (myScrollView.frame.width / 2 ) + 300), y:(myImageView.center.y - (myScrollView.frame.height / 2) + 500))

5. 關於 ScrollView 中 indicator 的設定

//set up the idicator of scrollview
myScrollView.indicatorStyle = .white
myScrollView.showsHorizontalScrollIndicator = true
myScrollView.showsVerticalScrollIndicator = true   

7. 將 ImageView放到 ScrollView上，再將 ScrollView 加入 View

        myScrollView.addSubview(myImageView)
        self.view.addSubview(myScrollView)