Event Handling in iOS

Transcript

1. © The App Business INTRODUCTION TO EVENTS Responder Chain & Friends.
2. © The App Business 2 What is an Event?
3. © The App Business 3 What is an Event? Why should you care about Events?
4. © The App Business 4 What is an Event? Why should you care about Events? How are Events handled in iOS?
5. © The App Business 5 What is an Event?
6. © The App Business What is an Event? 6 Input Something Happens Response
7. © The App Business 7 Something Happens
8. © The App Business 8 Events
9. © The App Business 9 
10. © The App Business 10 An event is a low-level record of a user action that is usually routed to the application in which the action occurred.
11. © The App Business 11
12. © The App Business 12 Events in iOS represent fingers touching views of an application or the user shaking the device.
13. © The App Business 13 What is an Event? Why should you care about Events? How are Events handled in iOS?
14. © The App Business 14 Why should you care about Events?
15. © The App Business Why should you care about Events? 15 Events are what make an app an app. We, as developers have the power to trigger and manipulate events. Solve event-related problems in very easy/creative ways. The Responder Chain is too cool to ignore.
16. © The App Business Why should you care about Events? 16 Events are what make an app an app. We, as developers have the power to trigger and manipulate events. Solve event-related problems in very easy/creative ways. The Responder Chain is too cool to ignore.
17. © The App Business Why should you care about Events? 17 Events are what make an app an app. We, as developers have the power to trigger and manipulate events. Solve event-related problems in very easy/creative ways. The Responder Chain is too cool to ignore.
18. © The App Business Why should you care about Events? 18 Events are what make an app an app. We, as developers have the power to trigger and manipulate events. Solve event-related problems in very easy/creative ways. The Responder Chain is too cool to ignore.
19. © The App Business Why should you care about Events? 19 Events are what make an app an app. We, as developers have the power to trigger and manipulate events. Solve event-related problems in very easy/creative ways. The Responder Chain is too cool to ignore.
20. © The App Business 20 What is an Event? Why should you care about Events? How are Events handled in iOS?
21. © The App Business 21 How are Events handled in iOS?
22. iOS Architecture: A Quick Zoom-Out Event Handling in iOS © The App Business How are Events handled in iOS? 22
23. © The App Business 23
24. © The App Business 24 iOS Architecture
25. © The App Business 25 iPhone Hardware Kernel, Device Drivers.
26. © The App Business 26 iPhone Hardware Kernel, Device Drivers. Core OS
27. © The App Business 27 iPhone Hardware Kernel, Device Drivers. Core OS Core Services
28. © The App Business 28 iPhone Hardware Kernel, Device Drivers. Core OS Core Services Media Services
29. © The App Business 29 iPhone Hardware Kernel, Device Drivers. Core OS Core Services Media Services Cocoa Touch
30. © The App Business 30 iPhone Hardware Kernel, Device Drivers. Core OS Core Services Media Services Cocoa Touch
31. © The App Business 31 Cocoa Touch
32. © The App Business 32 UIKIT RESPONDER iOS
33. © The App Business 33 UIEVENT
34. © The App Business 34 UIRESPONDER
35. © The App Business 35 UIRESPONDER
36. Represents objects that can handle and respond to arbitrary events. © The App Business UIResponder 36
37. © The App Business 37 Responder Chain
38. © The App Business 38 Responder Chain Linked List of UIResponder objects.
39. © The App Business 39 Responder Chain Who creates this?
40. © The App Business 40 Responder Chain UIKit
41. © The App Business 41 UIView UIViewController UIWindow UIApplication UIResponder
42. © The App Business 42
43. Process UIEvents Forward Unhandled Events © The App Business UIResponder Responsibilities 43
44. © The App Business Process UIEvents 44 UIKIT RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField
45. © The App Business Process UIEvents 45 UIKIT RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField
46. Process UIEvents Forward Unhandled Events © The App Business UIResponder Responsibilities 46
47. © The App Business Forward Unhandled Events 47 UIKIT RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField
48. © The App Business Forward Unhandled Events 48 UIKIT RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField
49. © The App Business 49 UIEVENT
50. © The App Business 50 Represents a single UIKit event that contains a type UIEvent And an optional sub-type (like a specific device motion shake).
51. © The App Business 51 System Event Queue UIApplication.shared.sendEvent() Touch Event UIEvent Instance Event Handling
52. © The App Business 52 System Event Queue UIApplication.shared.sendEvent() Touch Event UIEvent Instance Event Handling
53. © The App Business 53 System Event Queue RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField Event Handling
54. © The App Business 54 System Event Queue RESPONDER CHAIN UIView UIViewController UIWindow UIApplication UITextField Event Handling
55. © The App Business Cocoa Touch Types of Events 55 Touch Events Press Events Shake-motion Events Remote Control Events Editing Menu Events
56. © The App Business 56 func touchesBegan(Set<UITouch>, with: UIEvent?) func touchesMoved(Set<UITouch>, with: UIEvent?) func touchesEnded(Set<UITouch>, with: UIEvent?) func touchesCancelled(Set<UITouch>, with: UIEvent?) func touchesEstimatedPropertiesUpdated(Set<UITouch>) Touch Events
57. © The App Business 57 Press Events func pressesBegan(Set<UIPress>, with: UIPressesEvent?) func pressesChanged(Set<UIPress>, with: UIPressesEvent?) func pressesEnded(Set<UIPress>, with: UIPressesEvent?) func pressesCancelled(Set<UIPress>, with: UIPressesEvent?)
58. © The App Business 58 Motion Events func motionBegan(UIEvent.EventSubtype, with: UIEvent?) func motionEnded(UIEvent.EventSubtype, with: UIEvent?) func motionCancelled(UIEvent.EventSubtype, with: UIEvent?)
59. © The App Business 59 Remote Control Events func remoteControlReceived(with: UIEvent?)
60. © The App Business 60 Taking Advantage of the Responder Chain
61. © The App Business 61 func addTarget(_ target: Any?, action: Selector, for controlEvents: UIControl.Event)
62. © The App Business 62 button.addTarget(self, action: #selector(pressedAction(_:)), for: .touchUpInside)
63. © The App Business 63 button.addTarget(self, action: #selector(pressedAction(_:)), for: .touchUpInside)
64. © The App Business 64 func sendAction(_ action: Selector, to target: Any?, for event: UIEvent?)
65. © The App Business 65 Action Messages that are sent by UIControl objects are not events.
66. © The App Business 66 Taking Advantage of the Responder Chain
67. © The App Business 67 button.addTarget(self, action: #selector(pressedAction(_:)), for: .touchUpInside)
68. © The App Business 68 button.addTarget(self, action: #selector(pressedAction(_:)), for: .touchUpInside)
69. © The App Business 69 button.addTarget(nil, action: #selector(pressedAction(_:)), for: .touchUpInside)
70. © The App Business 70 Taking Advantage of the Responder Chain UIControl by setting target to nil, can send actions up the responder chain.
71. © The App Business 71 Taking Advantage of the Responder Chain Although they’re not events.
72. © The App Business 72 Taking Advantage of the Responder Chain
73. © The App Business 73 Example
74. © The App Business 74
75. © The App Business 75 View Controller Table View Table View Data Source Table View Cell Card View Checkbox
76. © The App Business 76 func indexPath(for cell: UITableViewCell) -> IndexPath?
77. © The App Business 77 View Controller Table View TableViewDataSourceDelegate Table View Data Source TableViewCellDelegate Table View Cell CardViewDelegate Card View CheckboxDelegate Checkbox
78. © The App Business 78 View Controller Responder Table View ꜛ Table View Data Source ꜛ Table View Cell CardViewDelegate sendAction to nil Card View CheckboxDelegate Checkbox
79. © The App Business 79 Implementation
80. © The App Business 80 @objc protocol TableViewCellCheckboxToggledAction: AnyObject { func tableViewCellCheckboxToggledAction(_ sender: TableViewCell) }
81. © The App Business 81 @objc protocol TableViewCellCheckboxToggledAction: AnyObject { func tableViewCellCheckboxToggledAction(_ sender: TableViewCell) } UIApplication.shared.sendAction( #selector(TableViewCellCheckboxToggledAction.tableViewCellCheckboxToggledAction(_:)), to: nil, from: self, for: nil)
82. © The App Business 82 @objc protocol TableViewCellCheckboxToggledAction: AnyObject { func tableViewCellCheckboxToggledAction(_ sender: TableViewCell) } UIApplication.shared.sendAction( #selector(TableViewCellCheckboxToggledAction.tableViewCellCheckboxToggledAction(_:)), to: nil, from: self, for: nil)
83. © The App Business 83 View Controller Responder Table View ꜛ Table View Data Source ꜛ Table View Cell CardViewDelegate sendAction to nil Card View CheckboxDelegate Checkbox
84. © The App Business 84 View Controller Responder Table View ꜛ Table View Data Source ꜛ Table View Cell CardViewDelegate sendAction to nil Card View CheckboxDelegate Checkbox
85. © The App Business 85 extension ViewController: TableViewCellCheckboxToggledAction { func tableViewCellCheckboxToggledAction(_ sender: TableViewCell) { guard let indexPathForSelectedCell = tableView.indexPath(for: sender) else { return } // We now have access to the indexPath of the cell where the checkbox was selected. \o/ }
86. © The App Business 86
87. THANK YOU © The App Business Thanks, Ben!