Ytukyg

I'm new to working with ScrollViews, and I'm doing it all programatically. I must be missing something super simple, but when I have no subviews, the scrollview shows up properly and scrolls up and down. But any time I add any subviews, the whole thing refuses to show up at all.

class DetailedPostScrollView: UIScrollView {



let topLabel: UILabel = {

    let label = UILabel()

    label.text = "this is the top"

    return label

}()



let bottomLabel: UILabel = {

    let label = UILabel()

    label.text = "this is the bottom"

    return label

}()



override init(frame: CGRect) {

    super.init(frame: frame)

    contentSize = CGSize(width: frame.width, height: 2000)

    alwaysBounceVertical = true



    addSubviewUsingAutoLayout(topLabel, bottomLabel)

    topLabel.centerXAnchor.constrain(to: self.centerXAnchor)

    topLabel.widthAnchor.constrain(to: 200)

    topLabel.heightAnchor.constrain(to: 50)

    topLabel.topAnchor.constrain(to: self.topAnchor, with: 100)



    bottomLabel.centerXAnchor.constrain(to: self.centerXAnchor)

    bottomLabel.widthAnchor.constrain(to: 200)

    bottomLabel.heightAnchor.constrain(to: 50)

    bottomLabel.bottomAnchor.constrain(to: self.bottomAnchor)



}



required init?(coder aDecoder: NSCoder) {

    fatalError("init(coder:) has not been implemented")

}

}

And in my viewController, I instantiate and add the scroll view

let detailedPostScrollView = DetailedPostScrollView(frame: UIScreen.main.bounds)

    detailedPostScrollView.backgroundColor = UIColor.purple

    view.addSubviewUsingAutoLayout(detailedPostScrollView)

Again, I"m sure it's something super simple but I checked out all the questions and tutorial videos and couldn't see where I"m going wrong. Thanks for your help.

Edit: It seems to work fine when I do it all programmatically from a viewcontroller, as follows :

 let scrollView: UIScrollView = {

        let sv = UIScrollView()

        sv.contentSize = CGSize(width: view.frame.width, height: 2000)

        sv.backgroundColor = UIColor.purple

        return sv

    }()



    view.addSubviewUsingAutoLayout(scrollView)

    scrollView.topAnchor.constrain(to: view.topAnchor, with: 100)

    scrollView.leadingAnchor.constrain(to: view.leadingAnchor)

    scrollView.trailingAnchor.constrain(to: view.trailingAnchor)

    scrollView.bottomAnchor.constrain(to: view.bottomAnchor)



    let topLabel: UILabel = {

        let label = UILabel()

        label.text = "this is the top"

        return label

    }()



    scrollView.addSubviewUsingAutoLayout(topLabel)

    topLabel.centerXAnchor.constrain(to: scrollView.centerXAnchor)

    topLabel.widthAnchor.constrain(to: 200)

    topLabel.heightAnchor.constrain(to: 50)

    topLabel.topAnchor.constrain(to: scrollView.topAnchor)

Something is off when I create a custom scrollview and instantiate that in my vc.

Try this :

class ViewController : UIViewController , UIScrollViewDelegate{

    var scrollView : UIScrollView! ;

    var containerView = UIView();

    var contentSize : CGSize {

        get {

            return CGSize(width: view.frame.width, height: 2000);

        }

    }



    override func viewDidLoad() {

        super.viewDidLoad();

        setupScrollView();

        setupItems();

    }



    override func viewDidLayoutSubviews() {

        super.viewDidLayoutSubviews();

        self.scrollView.frame = self.view.bounds;

        containerView.frame = CGRect(x: 0, y: 0, width: contentSize.width, height: contentSize.height);

    }



    private func setupScrollView() {

        scrollView = UIScrollView();

        scrollView.delegate = self;

        scrollView.backgroundColor = .white;

        scrollView.contentSize = contentSize;

        self.view.addSubview(scrollView);



        containerView.backgroundColor = .purple;

        self.scrollView.addSubview(containerView);

    }

    private func setupItems() {

        let topButton = UIButton();

        topButton.translatesAutoresizingMaskIntoConstraints = false;

        topButton.setTitle("TOP BUTTON", for: .normal);

        topButton.setTitleColor(.white, for: .normal);

        self.containerView.addSubview(topButton);



        let bottomTextField = UITextField();

        bottomTextField.translatesAutoresizingMaskIntoConstraints = false;

        bottomTextField.borderStyle = .roundedRect;

        bottomTextField.placeholder = "BOTTOM TEXT FIELD";

        self.containerView.addSubview(bottomTextField);



        topButton.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true;

        topButton.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 50).isActive = true;

        topButton.widthAnchor.constraint(equalToConstant: 100).isActive = true;

        topButton.heightAnchor.constraint(equalToConstant: 50).isActive = true;



        bottomTextField.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true;

        bottomTextField.bottomAnchor.constraint(equalTo: containerView.bottomAnchor, constant: -50).isActive = true;

        bottomTextField.widthAnchor.constraint(equalToConstant: 200).isActive = true;

        bottomTextField.heightAnchor.constraint(equalToConstant: 40).isActive = true;

    }



}

Set the scroll view frame to view bound in viewDidLayoutViews instead of using the layout , and add a container view as a subview for scroll view and set the size to same content size for scroll view again in viewDidLayoutViews so when ever user rotate the phone he get the correct width , and finally add all your views to container view .