Introducing ScrollingCardView for iOS
For Project Prox, we were asked to implement a design1 like this:
Specifically, this is a card view that:
- Hugs its content, dynamically expanding the height when the content does
- Will scroll its content if the content is taller than the card
After some searching, we discovered that no such widgets existed! Hoping our efforts could be useful to others, we created the ScrollingCardView library.
Usage
ScrollingCardView is used much like any other view.
First, create your view, enable autolayout, and add it to the view hierarchy:
let cardView = ScrollingCardView()
cardView.translatesAutoresizingMaskIntoConstraints = false
parentView.addSubview(cardView) // e.g. parent could be the ViewController's
Then constrain the card view as you would any other view:
NSLayoutConstraint.activate([
cardView.topAnchor.constraint(
equalTo: topLayoutGuide.bottomAnchor, constant: 16),
cardView.leadingAnchor.constraint(
equalTo: view.leadingAnchor, constant: 16),
cardView.trailingAnchor.constraint(
equalTo: view.trailingAnchor, constant: -16),
// If you don't constrain the height, the card
// will grow to match its intrinsic content size.
// Or use lessThanOrEqualTo to allow your card
// view to grow only until a certain size, e.g.
// the size of the screen.
cardView.bottomAnchor.constraint(
lessThanOrEqualTo: bottomLayoutGuide.topAnchor, constant: -16),
// Or you can constrain it to a particular height:
// cardView.bottomAnchor.constraint(
// equalTo: bottomLayoutGuide.topAnchor, constant: -16),
// cardView.heightAnchor.constraint(equalToConstant: 300),
])
Finally, specify the card view’s content:
// 3. Set your card view's content.
let content = UILabel()
content.text = "Hello world!"
content.numberOfLines = 0
cardView.contentView = content
The card view comes with smart visual defaults (including a shadow), but you can also customize them:
cardView.backgroundColor = .white
cardView.cornerRadius = 2
cardView.layer.shadowOffset = CGSize(width: 0, height: 2)
cardView.layer.shadowRadius = 2
cardView.layer.shadowOpacity = 0.4
Want it? ScrollingCardView is available on CocoaPods: you can find installation instructions and the source on GitHub.
Questions? Feature requests? File an issue or find us on #mobile.
Notes
1: This particular design was not actually used because we felt we could provide a better user experience if we also moved the card itself, which lets the user fill the screen with the long-form content they were trying to read. Further discussion in prox#372.
