Com quantas views se faz uma APP?

1. Com quantas views se faz uma APP? Auto Layout com Layout Anchor, Stack Views e Criatividade
2. Storyboards? XIBs? View Code? Layout Anchor Stack Views Bônus Conclusão Agenda
3. Storyboards? XIBs? View Code?
5. H:|-[left]-50—[right]-| NSLayoutContraint
6. Layout Anchor
7. "# NSLayoutContraint
8. – Documentação da Apple “Ainda que a classe NSLayoutAnchor tenha a checagem adicional de tipo, ainda é possível criar constraints inválidas. Por exemplo, o compilador permite que você configure a constraint leadingAnchor de uma view com a leftAnchor de outra view, pois ambas são instâncias de NSLayoutXAxisAnchor. Entretanto, Auto Layout não permite constraints que misturem atributos de leading e trailing com atributos de left ou right. Como resultado, as constraints vão quebrar em tempo de execução.”
10. final class BusinessCardComponent { let photoImageView: UIImageView let nameLabel: UILabel let titleLabel: UILabel let phoneLabel: UILabel let emailLabel: UILabel // ... } Layout Anchor
11. final class SeniorBusinessCardView: UIView {
 private let businessCardComponents: BusinessCardComponents init(businessCardComponents: BusinessCardComponents) { self.businessCardComponents = businessCardComponents super.init(frame: .zero) setupViewHierarchy() setupConstraints() } private func setupViewHierarchy() { addSubview(businessCardComponents.photoImageView) } private func setupConstraints() { businessCardComponents.photoImageView.topAnchor.constraint(equalTo: topAnchor).isActive = true businessCardComponents.photoImageView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true businessCardComponents.photoImageView.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true businessCardComponents.photoImageView.heightAnchor.constraint(equalToConstant: imageHeight).isActive = true // ... } } Layout Anchor
12. extension UIView { @discardableResult func topAnchor(equalTo anchor: NSLayoutYAxisAnchor, constant: CGFloat = 0) -> Self { topAnchor.constraint(equalTo: anchor, constant: constant).isActive = true return self } @discardableResult func bottomAnchor(equalTo anchor: NSLayoutYAxisAnchor, constant: CGFloat = 0) -> Self { bottomAnchor.constraint(equalTo: anchor, constant: constant).isActive = true return self } // ... } Layout Anchor
13. final class SeniorBusinessCardView: UIView { // ... private func setupConstraints() { businessCardComponents.photoImageView .topAnchor(equalTo: topAnchor) .leadingAnchor(equalTo: leadingAnchor) .trailingAnchor(equalTo: trailingAnchor) .heightAnchor(equalTo: imageHeight) } } Layout Anchor
14. Stack Views
16. – Documentação da Apple “A stack view está de acordo com Auto Layout (é baseada no layout de constraints do sistema) para organizar e alinhar uma lista de views de acordo com sua especificação. Para tirar proveito da stack view, você precisa saber o básico sobre as contraints do Auto Layout, como descrito no Guia do Auto Layout”
17. final class JuniorBusinessCardView: UIView { // ... private let stackContentContainer: UIStackView = { let stack = UIStackView(frame: .zero) stack.axis = .vertical stack.translatesAutoresizingMaskIntoConstraints = false return stack }() init(businessCardComponents: BusinessCardComponents) { self.businessCardComponents = businessCardComponents super.init(frame: .zero) setupViewHierarchy() setupConstraints() } private func setupViewHierarchy() { stackContentContainer.addArrangedSubview(businessCardComponents.nameLabel) // ... } private func setupConstraints() { // ... stackContentContainer .topAnchor(equalTo: businessCardComponents.photoImageView.topAnchor) .leadingAnchor(equalTo: businessCardComponents.photoImageView.trailingAnchor, constant: defaultMargin) .trailingAnchor(equalTo: trailingAnchor, constant: defaultMargin) .bottomAnchor(equalTo: businessCardComponents.photoImageView.bottomAnchor) } } Stack Views
18. Bônus
19. Conclusão
20. ☝ ❔ • http://equinocios.com/view-code/2017/03/18/com-quantas-views-se-faz-um-APP/ • https://developer.apple.com/reference/uikit/nslayoutanchor • https://developer.apple.com/library/etc/redirect/xcode/content/1189/documentation/ UserExperience/Conceptual/AutolayoutPG/index.html#//apple_ref/doc/uid/TP40010853 • https://developer.apple.com/reference/appkit/nsstackview • CocoaHeads Slack: ronan • ronanrodrigo.com