Developing for tvOS and working with focus engine

Talk from CocoaHeads Kraków #20, 12.05.2016

Transcript

1. Developing for tvOS and working with focus engine Michał Ciuba @michalciuba
2. Agenda • Apple TV - introduction • Developing for tvOS: the good, the bad and the ugly • Focus engine • Demo
3. Apple TV
4. Apple TV • A set-top box and a simple game console • Siri remote (touch surface, microphone, accelerometer), optional game controllers • A8 processor, 2 GB RAM, 32/64 GB storage • 24 million to sell in 2016 (estimated)
5. tvOS 9.x • SDK available since Apple TV 4th gen (late 2015) • Based on iOS 9 • Apps: native (Objective-C / Swift) or TVML + JS
6. Developing for tvOS
8. The good • Very similar to iOS (most of the frameworks are available) • UIKit components work well with new input methods (remote, voice) • New parallax effects, easy to implement in apps
9. The good • All the new iOS 9 APIs are there • No need to worry about backward compatibility (at least now) • One screen size (1920 x 1080 @1x), no rotation • Human Interface Guidelines give good hints for UI design
11. The bad • No Safari, WebKit, web views • Unavailable frameworks (MapKit, Photos, Social, Multipeer Connectivity, HomeKit…) • Only few gestures available (tap, swipe, long press, pan)
12. The bad • The device is always connected, so… • App size is limited (200 MB). On-demand resources have to be used to download more assets • No local persistent storage, app data can be deleted between launches. Use CloudKit instead
14. The ugly
15. Focus engine
16. Focus engine • No touch screen, interface is controlled indirectly • Remote: swipe up/down/left/right + tap (no „multitouch”) • Menu button works as „back”button • UI elements become focused (highlighted) as the user navigates through them
17. Focus engine Standard UIKit elements look different on tvOS: they show what’s focused
18. Focus engine • Some items are focusable (UIButton), some not (UILabel) • UIView has canBecomeFocused property • You can support focus in custom views • Focus updates are initiated by the user • You can also request focus update programatically
19. UIFocusEnvironment • Implemented by UIViewController, UIView • Indirect control over the focus engine (you can’t set the focused view explicitly) • Setting initial focus • Responding to focus changes (animations!)
20. UIFocusEnvironment weak public var preferredFocusedView: UIView? { get } public func setNeedsFocusUpdate() public func updateFocusIfNeeded() public func shouldUpdateFocusInContext(context: UIFocusUpdateContext) -> Bool public func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator)
21. UIFocusEnvironment weak public var preferredFocusedView: UIView? { get } public func setNeedsFocusUpdate() public func updateFocusIfNeeded() public func shouldUpdateFocusInContext(context: UIFocusUpdateContext) -> Bool public func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator)
22. UIFocusEnvironment weak public var preferredFocusedView: UIView? { get } public func setNeedsFocusUpdate() public func updateFocusIfNeeded() public func shouldUpdateFocusInContext(context: UIFocusUpdateContext) -> Bool public func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator)
23. UIFocusGuide • Inherits from UILayoutGuide • „represents an invisible, focusable region that can redirect focus movement to other views” • Useful in custom views • Unavailable in Interface Builder
24. UIFocusGuide
25. Parallax effect • set adjustsImageWhenAncestorFocused on UIImageView • works with layered and plain images (also app icons) • public var focusedFrameGuide: UILayoutGuide { get }
26. Parallax effect Layered images (.lsr)
27. Parallax effect Layered images (.lsr)
28. Any questions so far?
30. Demo
31. Thank you! Michał Ciuba @michalciuba