#scroll view

A Scroll View can be used to present content that is larger than the screen. In this tutorial a scroll view containing colored circles will be displayed. The scroll view can be scrolled horizontally. SwiftUI requires Xcode 11 and MacOS Catalina, which can be download at the Apple developer portal.

Open Xcode and either click Create a new Xcode project in Xcode’s startup window, or choose File > New > Project. In the template selector, select iOS as the platform, select the Single View App template, and then click Next. Enter SwiftUIScrollViewTutorial as the Product Name, select the Use SwiftUI checkbox, and click Next. Choose a location to save the project on your Mac.

In the canvas, click Resume to display the preview. If the canvas isn’t visible, select Editor > Editor and Canvas to show it.

In the Project navigator, click to select ContentView.swift. Change the code inside the ContentView struct to

struct ContentView: View { // 1. var items = [Color.red, Color.orange, Color.yellow, Color.green, Color.blue, Color.purple] var body: some View { // 2. ScrollView(Axis.Set.horizontal, showsIndicators: true) { HStack { ForEach(self.items, id: \.self) { item in // 3. Circle() .fill(item) .frame(width: 100, height: 100) } } } } }

An array of colours is declared.

A horizontal scroll view is displayed, the scroll indicators are visible during scrolling,.

a range of coloured circles is displayed inside the scroll view.

Go to the preview canvas and select the Live Preview button. The coloured circles can be scrolled horizontally.

Scroll Views in combination with paging enabled allows the user to scroll page by page. In this tutorial we will create some views, which can be scrolled using paging.This tutorial is made with Xcode 10 and built for iOS 12.

Open Xcode and create a new Single View App.

For product name, use IOSScrollViewPagingTutorial and then fill out the Organization Name and Organization Identifier with your customary values. Enter Swift as Language and choose Next.

Go to the Storyboard, drag a Scroll View from the Object Library to the View Controller inside the Storyboard. 

Open the Assistant Editor and make sure the ViewController.swift file is visible. Ctrl + drag from the Scroll View to the ViewController class and create the following Outlet

In The ViewController class add the following properties

let colors = [UIColor.red, UIColor.blue, UIColor.green, UIColor.yellow] var frame = CGRect(x: 0, y: 0, width: 0, height: 0)

An Array containing colors and an empty CGrect are created. Next, change the viewDidLoad method to.

override func viewDidLoad() { super.viewDidLoad() for index in 0..<colors.count { frame.origin.x = scrollView.frame.size.width * CGFloat(index) frame.size = scrollView.frame.size let subView = UIView(frame: frame) subView.backgroundColor = colors[index] scrollView.addSubview(subView) } scrollView.contentSize = CGSize(width: scrollView.frame.size.width * CGFloat(colors.count), height: scrollView.frame.size.height) }

The for loops iterates through the color array, where each color is used as the background of an UIView. These views are then added as a subview of the Scroll View. The paging is enabled with the pagingEnabled property. Build and Run the project. Swipe right to scroll through the colored views, page by page.

A Scroll View provides support for displaying content that is larger than the size of the application’s window. In this tutorial a large image is added inside a Scroll View. This image can be panned around. This tutorial is made with Xcode 10 and built for iOS 12.

Open Xcode and create a new Single View App.

For product name, use IOS12ScrollViewTutorial and then fill out the Organization Name and Organization Identifier with your customary values. Enter Swift as Language and choose Next.

Download the image and drag it from the Finder to the Assets Library. Go to the ViewController.swift file and add the follwing properties

var imageView: UIImageView! var scrollView: UIScrollView!

Change the viewDidLoad method to

override func viewDidLoad() { super.viewDidLoad() // 1 imageView = UIImageView(image: UIImage(named: "strandvagen.jpg")) // 2 scrollView = UIScrollView(frame: view.bounds) scrollView.backgroundColor = UIColor.black // 3 scrollView.contentSize = imageView.bounds.size // 4 scrollView.addSubview(imageView) view.addSubview(scrollView) }

The large image is added to the Image View

A Scroll View is initialized with the size of the whole screen and a black background color

The contentSize property is the size of the content that you need to display in the scroll view.

The Image View is added as a subview of the Scroll View which is added as a subview of the main View.

Build and Run the project and pan around to view different portions of the image.

original source : https://stackoverflow.com/questions/44931898/using-scrollview-programmatically-in-swift-3

scroll view 사용이 기본예시

Two things.

1. Add the labels to scroll view, not your view

You want your label to scroll with scroll view, then you should not add it on your view. When running your code, you can scroll but the fixed label there is pinned to your view, not on your scroll view

2. Make sure you added your constraints correctly

Try it on your storyboard about what combination of constraint is enough for a view. At least 4 constraints are needed for a label.

Bottom line

Here is a modified version of your code. For constraint I added padding left, padding top, width and height and it works. My code is

let labelOne: UILabel = {    let label = UILabel()    label.text = "Scroll Top"    label.backgroundColor = .red    label.translatesAutoresizingMaskIntoConstraints = false    return label }() let labelTwo: UILabel = {    let label = UILabel()    label.text = "Scroll Bottom"    label.backgroundColor = .green    label.translatesAutoresizingMaskIntoConstraints = false    return label }() override func viewDidLoad() {    super.viewDidLoad()    let screensize: CGRect = UIScreen.main.bounds    let screenWidth = screensize.width    let screenHeight = screensize.height    var scrollView: UIScrollView!    scrollView = UIScrollView(frame: CGRect(x: 0, y: 120, width: screenWidth, height: screenHeight))    scrollView.addSubview(labelTwo)    NSLayoutConstraint(item: labelTwo, attribute: .leading, relatedBy: .equal, toItem: scrollView, attribute: .leadingMargin, multiplier: 1, constant: 10).isActive = true    NSLayoutConstraint(item: labelTwo, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 200).isActive = true    NSLayoutConstraint(item: labelTwo, attribute: .top, relatedBy: .equal, toItem: scrollView, attribute: .topMargin, multiplier: 1, constant: 10).isActive = true    NSLayoutConstraint(item: labelTwo, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 30).isActive = true    scrollView.contentSize = CGSize(width: screenWidth, height: 2000)    view.addSubview(scrollView) }

And the scroll view looks like this