ADDC 2019 - Daniel Steinberg - Bringing SwiftUI to your App

What changes in the way you design your app with SwiftUI? Everything and nothing. In this fast-paced talk we’ll look at how to get the most out of Apple’s new Swift-friendly declarative UI framework and the impact it has on how you envision and architect your app.

Transcript

1. The Changes Coming in SwiftUI ADDC 2019 Barcelona Daniel H Steinberg dimsumthinking.com *
2. * I have worked with SwiftUI for twenty years
3. * I have worked with SwiftUI for twenty years
4. * I have worked with SwiftUI for twenty years three weeks
5. * I have worked with SwiftUI for twenty years three weeks almost
6. * I have worked with SwiftUI for three weeks * The syntax will change
7. * I have worked with SwiftUI for three weeks * The syntax will change * SwiftUI is how we will code for Apple platforms
8. The Changes Coming in SwiftUI ADDC 2019 Barcelona Daniel H Steinberg dimsumthinking.com
9. The Old Days
10. The Old Days very
11. I'm a label
12. let label = UILabel(frame: CGRect(x: 0, y: 100, width: 380, height: 40))
13. let label = UILabel(frame: CGRect(x: 0, y: 100, width: 380, height: 40))
14. let label = UILabel(frame: CGRect(x: 0, y: 101, width: 380, height: 40))
15. I'm a label
16. I'm a label
17. Conditional Code
18. I'm a label
19. I'm a label
20. Pixels -> Points
21. I'm a label
22. I'm a label
23. I'm a label
24. I'm a label
25. Autolayout
26. Gained flexibility for different size classes
27. Lost pixel-perfect design
28. The Old Days
29. cell.text = "Hello, World!"
30. cell.textLabel.text = "Hello, World!"
31. private func setUpLabel() { label.textColor = .white label.textAlignment = .center label.text = "0" view.addSubview(label) }
32. private func setUpLabel() { label.textColor = .white label.textAlignment = .center label.text = "0" view.addSubview(label) }
33. private func setUpLabel() { label.textColor = .white label.textAlignment = .center label.text = "0" view.addSubview(label) }
34. private func setUpLabel() { label.textColor = .white label.textAlignment = .center label.text = "0" view.addSubview(label) }
35. private func setUpLabel() { label.textColor = .white label.textAlignment = .center label.text = "0" view.addSubview(label) }
36. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
37. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
38. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
39. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
40. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
41. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
42. private func setUpButton() { button.setTitle("Increase", for: .normal) button.frame = CGRect(x: 0, y: 300, width: 380, height: 40) button.addTarget(self, action: #selector(increaseValue), for: .touchUpInside) view.addSubview(button) }
43. @objc private func increaseValue(){ value += 1 label.text = value.description }
44. @objc private func increaseValue(){ value += 1 label.text = value.description }
45. @objc private func increaseValue(){ value += 1 label.text = value.description }
46. @objc private func increaseValue(){ value += 1 label.text = value.description } Classic Controller Code
47. SwiftUI
49. SwiftUI
50. struct ContentView: View { var body: some View { Text("0") } }
51. struct ContentView: View { var body: some View { Text("0") } }
52. struct ContentView: View { var body: some View { Text("0") } }
53. struct ContentView: View { var body: some View { return Text("0") } }
54. struct ContentView: View { var body: some View { Text("0") } }
56. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
57. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
58. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
59. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } } cell.textLabel.text
60. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
61. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
62. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
63. struct ContentView: View { var body: some View { VStack { Text("0") Button(action: {}) { Text("Increase") } } } }
65. struct ContentView: View { var body: some View { VStack { Text("0") .padding() Button(action: {}) { Text("Increase") } } } }
67. struct ContentView: View { var body: some View { VStack { Text("0") .padding() Button(action: {}) { Text("Increase") } } } }
68. @objc private func increaseValue(){ value += 1 label.text = value.description } Flashback
69. struct ContentView: View { var body: some View { VStack { Text("0") .padding() Button(action: {}) { Text("Increase") } } } }
70. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
71. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
72. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
73. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
74. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
75. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
76. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
77. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
78. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
79. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
80. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
81. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
82. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
84. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
85. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } } Layout/Content/Behavior
86. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } } Layout/Content/Behavior
87. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
88. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } }
89. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
90. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
91. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
92. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
93. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } } Extract the Text
94. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
95. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
96. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
97. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
98. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
99. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
100. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
101. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
102. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
103. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
104. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
105. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
106. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
107. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
108. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() IncreaseButton(value: $value) } } }
109. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() IncreaseButton(value: $value) } } }
110. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
111. struct IncreaseButton: View { var body: some View { Button() { Text("Increase") } } } struct ValueDisplay: View { var body: some View { Text("\(value)") } }
112. SwiftUI
114. Note to developers
115. Note to developers Hire a designer
116. The example has: •Components: Text, TextField, Slider, Buttons, Drawing •Containers: VStack, HStack, ZStack, Geometry •Navigation: Tabs, Nav, Detail View •Data: State, Binding, Object Binding
117. The example has: •Components: Text, TextField, Slider, Buttons, Drawing •Containers: VStack, HStack, ZStack, Geometry •Navigation: Tabs, Nav, Detail View •Data: State, Binding, Object Binding
118. The example has: •Components: Text, TextField, Slider, Buttons, Drawing •Containers: VStack, HStack, ZStack, Geometry •Navigation: Tabs, Nav, Detail View •Data: State, Binding, Object Binding
119. The example has: •Components: Text, TextField, Slider, Buttons, Drawing •Containers: VStack, HStack, ZStack, Geometry •Navigation: Tabs, Nav, Detail View •Data: State, Binding, Object Binding
120. The example has: •Components: Text, TextField, Slider, Buttons, Drawing •Containers: VStack, HStack, ZStack, Geometry •Navigation: Tabs, Nav, Detail View •Data: State, Binding, Object Binding
121. struct ContentView: View { var body: some View { TabbedView { MoodEntryView() .tabItemLabel(Text("Face")) .tag(0) HistoryView() .tabItemLabel(Text("History")) .tag(1) } } }
122. struct ContentView: View { var body: some View { TabbedView { MoodEntryView() .tabItemLabel(Text("Face")) .tag(0) HistoryView() .tabItemLabel(Text("History")) .tag(1) } } }
124. var body: some View { VStack { FaceView(mood: $mood) FaceSlider(mood: $mood) TextField($message, placeholder: Text("What's going on")) Button(action: {history.add(mood: Mood(for: self.mood), title: self.message) self.message = "" self.mood = 2 }){ Text("Record Mood") }.disabled(buttonDisabled) } }
125. var body: some View { VStack { FaceView(mood: $mood) FaceSlider(mood: $mood) TextField($message, placeholder: Text("What's going on")) Button(action: {history.add(mood: Mood(for: self.mood), title: self.message) self.message = "" self.mood = 2 }){ Text("Record Mood") }.disabled(buttonDisabled) } }
126. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
127. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
128. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
129. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
131. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: 15) }.aspectRatio(1, contentMode: .fit) } } }
135. Use the geometry
136. Use the geometry Allows us to listen to our designers
137. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
138. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
139. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
141. struct FaceView: View { @Binding var mood: Double var body: some View { GeometryReader {geometry in ZStack { Circle().fill(faceColor(mood: self.mood)) Eyes(size: min(for: geometry)) mouth(mood: self.mood, size: min(for: geometry)) .stroke(Color.black, lineWidth: min(for: geometry) / 50 ) }.aspectRatio(1, contentMode: .fit) } } }
144. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
146. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
148. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
150. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
152. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
154. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
156. HStack(alignment: .top) { Image(uiImage: record.image) .resizable() .frame(width: 40, height: 40) .padding([.leading, .trailing]) Text(record.title) .font(.headline) .lineLimit(3) Spacer() VStack(alignment: .trailing){ Text(record.time) .font(.body) Text(record.date) .font(.footnote) }.padding([.leading, .trailing]) }
158. View Requires •Image •Text (title) •Text (time) •Text (date)
159. View Requires •Image •Text (title) •Text (time) •Text (date) Model Provides •Mood (enum) •String (title) •Date (timestamp)
160. View Model
161. struct MoodRecordViewModel { let moodRecord: MoodRecord }
162. struct MoodRecordViewModel { let moodRecord: MoodRecord }
163. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
164. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
165. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
166. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
167. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
168. extension MoodRecordViewModel { public var title: String { return moodRecord.title } public var image: UIImage { guard let image = UIImage(named: moodRecord.mood.description) else {fatalError()} return image } public var time: String { return timeFormatter.string(from: moodRecord.timeStamp) } public var date: String { return dateFormatter.string(from: moodRecord.timeStamp) } }
169. Updates
171. history
172. public class History { lazy var moodRecords = initializeMoodRecords() }
173. public class History { lazy var moodRecords = initializeMoodRecords() }
174. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
175. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
176. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
177. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
178. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
179. extension History { func add(mood: Mood, title: String) { moodRecords.append(MoodRecord(mood: mood, title: title)) sendUpdate() } func clear() { moodRecords.removeAll() sendUpdate() } }
180. Updates
181. @State
182. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
183. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
184. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { Text("\(value)") .padding() Button(action: {self.value += 1}) { Text("Increase") } } } }
185. @Binding
186. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
187. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
188. struct IncreaseButton: View { @Binding var value: Int var body: some View { Button(action: increaseValue) { Text("Increase") } } private func increaseValue() { value += 1 } }
189. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() IncreaseButton(value: $value) } } }
190. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() IncreaseButton(value: $value) } } }
191. struct ContentView: View { @State var value: Int = 0 var body: some View { VStack { ValueDisplay(value: $value) .padding() IncreaseButton(value: $value) } } }
192. struct ValueDisplay: View { @Binding var value: Int var body: some View { Text("\(value)") } }
193. history
194. @ObjectBinding
195. public class History: BindableObject { lazy var moodRecords = initializeMoodRecords() let didChange = PassthroughSubject<History, Never>() }
196. public class History: BindableObject { lazy var moodRecords = initializeMoodRecords() let didChange = PassthroughSubject<History, Never>() }
197. public class History: BindableObject { lazy var moodRecords = initializeMoodRecords() let didChange = PassthroughSubject<History, Never>() }
198. extension History { func sendUpdate() { updateMoodRecords() didChange.send(self) } private func updateMoodRecords() {…} }
199. extension History { func sendUpdate() { updateMoodRecords() didChange.send(self) } private func updateMoodRecords() {…} }
200. struct HistoryView: View { @ObjectBinding private var moodHistory = history
201. struct HistoryView: View { @ObjectBinding private var moodHistory = history
202. history
203. history
204. history
205. SwiftUI
206. Caution:
207. Caution: It is early days.
208. Caution: It is early days. Much will change.
209. It is our future
210. The Changes Coming in SwiftUI ADDC 2019 Barcelona Daniel H Steinberg dimsumthinking.com