Swift - 如何使视图 controller 可滚动？

Question

I have a view controller with some elements in it.

class MyViewController: UIViewController {
    // ......
}

This is what I want: example of what I want

This is what my app looks like:

I want to make the two elements (an imageView and a button) to be vertically scrollable like the example.

What should I do? I have checked UIScrollView , but still don't know how to do it. Can you show me some code? Thanks!

Answer 1

There is an UI Component inside UIKit called UIScrollView . This Component can be used to achieve the Scrolling Behaviour you probably aim for.

Check out the official Documentation by Apple UIScrollView |Apple Developer Documentation

Another great resource for getting started with UIScrollViews is this one. UIScrollView Tutorial: Getting Started

Answer 2

One way to do this is programmatically create an UIScrollView in your UIViewController .

To control the scrollability you can set the ScrollView contentSize property. In the following sample we match contentSize.width with self.view.frame.size.width to prevent horizontal scroll.

So, to achieve your goal, you must add your components inside the scrollView using scrollView.addSubview

This is a simple sample of a UIScrollView with a red UIView inside:

import UIKit

class MyViewController: UIViewController, UIScrollViewDelegate {
    
    lazy var scrollView: UIScrollView = {
        let scroll = UIScrollView()
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.delegate = self
        scroll.contentSize = CGSize(width: self.view.frame.size.width, height: 1000)
        return scroll
    }()
    
    lazy var redView:UIView = {
        let redview = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
        redview.backgroundColor = .red
        return redview
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(scrollView)
        scrollView.addSubview(redView)
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        let layout = view.safeAreaLayoutGuide
        scrollView.centerXAnchor.constraint(equalTo: layout.centerXAnchor).isActive = true
        scrollView.centerYAnchor.constraint(equalTo: layout.centerYAnchor).isActive = true
        scrollView.widthAnchor.constraint(equalTo: layout.widthAnchor).isActive = true
        scrollView.heightAnchor.constraint(equalTo: layout.heightAnchor).isActive = true
    }
    
    
}