UIViewController 内部的 UIScrollView 不水平滚动

Question

I have created a UIScrollView inside of a UIViewController. I have added a UIView inside of my UIScrollView with one label inside of the UIView. The plan is to eventually add 3 very large UIButtons that is why I need a scroll view. I have not used storyboard and it is done all programmatically. I cannot get the UIScrollView to work.

class ChooseCategoryPostViewController: UIViewController, UIScrollViewDelegate {

       let scrollView: UIScrollView = {
       let sv = UIScrollView()
       sv.backgroundColor = .green
       return sv
                     }()

       let myView: UIView = {
       let view = UIView()
       view.backgroundColor = .red
       return view
                    }()

       let test: UILabel = {
          let label = UILabel()
          label.text = "test label"
          label.font = UIFont.boldSystemFont(ofSize: 15)
          label.textAlignment = .center
          return label
      }()


         override func viewDidLoad() {
    view.addSubview(scrollView)
    scrollView.addSubview(myView)
    
    scrollView.anchor(top: topTitle.bottomAnchor, left: nil, bottom: nil, right: nil, paddingTop: 200, paddingLeft: 0, paddingBottom: 0, paddingRight: 0, width: view.frame.width, height: 200)
    myView.anchor(top: scrollView.topAnchor, left: scrollView.leftAnchor, bottom: scrollView.bottomAnchor, right: nil, paddingTop: 0, paddingLeft: 10, paddingBottom: 0, paddingRight: 0, width: 1700, height: 200)
    myView.addSubview(test)
    test.anchor(top: myView.topAnchor, left: nil, bottom: nil, right: myView.rightAnchor, paddingTop: 20, paddingLeft: 0, paddingBottom: 0, paddingRight: 20, width: 0, height: 0)

}

 override func viewDidLayoutSubviews() {
    scrollView.isScrollEnabled = true
    // Do any additional setup after loading the view
    scrollView.contentSize = CGSize(width: view.frame.width, height: 200)
}

Answer 1

You need to make sure that the width of the scroll view contentSize is greater than the width of the scroll view itself. Something as simple as the following should cause horizontal scrolling to happen:

override func viewDidLayoutSubviews() {
    scrollView.isScrollEnabled = true
    // Do any additional setup after loading the view
    scrollView.contentSize = CGSize(width: view.frame.width * 2, height: 200)
}