Notes WWDC 2021 : Focus on iPad keyboard navigation

Mes notes pour la session Focus on iPad keyboard navigation de la WWDC 2021.

With iOS 15 SDK, keyboard navigation enabled by default for:

• Text fields
• Text views
• Sidebars

Opt-in for:

• Collection views
• Table views
• Custom views

Focus system: same as tvOS, with additional features

Focusability

override var canBecomeFocused: Bool { true }

class MyViewController: UICollectionViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    self.collectionView.allowsFocus = true
  }
}

class MyCollectionViewDelegate: NSObject, UICollectionViewDelegate {
  func collectionView(_ collectionView: UICollectionView, canFocusItemAt indexPath: IndexPath) -> Bool {
    return true
  }
}

Appearance

“Halo” as the default effect, customizable

let focusEffect = UIFocusHaloEffect(roundedRect: self.bounds, cornerRadius: self.layer.cornerRadius, curve: .continuous)

// make sure the effect is added right above the image view
focusEffect.referenceView = self.imageView

// make sure the effect is added to our scroll view
focusEffect.containerView = self.scrollView

self.focusEffect = focusEffect

Sidebars

selectionFollowsFocus, available on collection views and table views. Can also be customized cell by cell.

Focus groups

• Tab key to switch groups, arrows to switch items within current group
• By default, environments inherit their parent environment’s group
• Can define item priority within its group

Responder chain

Focus and first responder synchronized.