Ecco un esempio completo di una verticale UIStackViewcomposta da multilinea UILabelcon altezza automatica.
Le etichette si avvolgono in base alla larghezza dello stackview e l'altezza dello stackview si basa sull'altezza di avvolgimento dell'etichetta. (Con questo approccio non è necessario incorporare le etichette in a UIView.) (Swift 5, iOS 12.2)
// A vertical stackview with multiline labels and automatic height.
class ThreeLabelStackView: UIStackView {
let label1 = UILabel()
let label2 = UILabel()
let label3 = UILabel()
init() {
super.init(frame: .zero)
self.translatesAutoresizingMaskIntoConstraints = false
self.axis = .vertical
self.distribution = .fill
self.alignment = .fill
label1.numberOfLines = 0
label2.numberOfLines = 0
label3.numberOfLines = 0
label1.lineBreakMode = .byWordWrapping
label2.lineBreakMode = .byWordWrapping
label3.lineBreakMode = .byWordWrapping
self.addArrangedSubview(label1)
self.addArrangedSubview(label2)
self.addArrangedSubview(label3)
// (Add some test data, a little spacing, and the background color
// make the labels easier to see visually.)
self.spacing = 1
label1.backgroundColor = .orange
label2.backgroundColor = .orange
label3.backgroundColor = .orange
label1.text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi."
label2.text = "Hello darkness my old friend..."
label3.text = "When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor, in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts, and earned my living by the labor of my hands only."
}
required init(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
}
Ecco un esempio ViewControllerche lo utilizza.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let myLabelStackView = ThreeLabelStackView()
self.view.addSubview(myLabelStackView)
// Set stackview width to its superview.
let widthConstraint = NSLayoutConstraint(item: myLabelStackView, attribute: NSLayoutConstraint.Attribute.width, relatedBy: NSLayoutConstraint.Relation.equal, toItem: self.view, attribute: NSLayoutConstraint.Attribute.width, multiplier: 1, constant: 0)
self.view.addConstraints([widthConstraint])
}
}
