#188: Add support to swiping to dismiss keyboard for UIKitBackend

Author: Vitor Silveira

Examples/Sources/NotesExample/ContentView.swift

@@ -38,10 +38,10 @@ struct ContentView: View {
 
     var textEditorBackground: Color {
         switch colorScheme {
-            case .light:
-                Color(0.8, 0.8, 0.8)
-            case .dark:
-                Color(0.18, 0.18, 0.18)
+        case .light:
+            Color(0.8, 0.8, 0.8)
+        case .dark:
+            Color(0.18, 0.18, 0.18)
         }
     }
 
@@ -142,6 +142,7 @@ struct ContentView: View {
                             .padding()
                             .background(textEditorBackground)
                             .cornerRadius(4)
+                            .scrollDismissesKeyboard(.interactively)
                     }
                 }
                 .padding()

Sources/SwiftCrossUI/Environment/EnvironmentValues.swift

@@ -77,6 +77,8 @@ public struct EnvironmentValues {
 
     /// Whether user interaction is enabled. Set by ``View/disabled(_:)``.
     public var isEnabled: Bool
+    
+    public var scrollDismissesKeyboardMode: ScrollDismissesKeyboardMode
 
     /// Called by view graph nodes when they resize due to an internal state
     /// change and end up changing size. Each view graph node sets its own
@@ -196,6 +198,7 @@ public struct EnvironmentValues {
         listStyle = .default
         toggleStyle = .button
         isEnabled = true
+        scrollDismissesKeyboardMode = .never
     }
 
     /// Returns a copy of the environment with the specified property set to the

Sources/SwiftCrossUI/Values/ScrollDismissesKeyboardMode.swift

@@ -0,0 +1,20 @@
+/// The ways that scrollable content can interact with the software keyboard.
+///
+/// Use this type in a call to the ``View/scrollDismissesKeyboard(_:)``
+/// modifier to specify the dismissal behavior of scrollable views.
+public enum ScrollDismissesKeyboardMode: Sendable {
+    /// Dismiss the keyboard as soon as scrolling starts.
+    case immediately
+
+    /// Enable people to interactively dismiss the keyboard as part of the
+    /// scroll operation.
+    ///
+    /// The software keyboard's position tracks the gesture that drives the
+    /// scroll operation if the gesture crosses into the keyboard's area of the
+    /// display. People can dismiss the keyboard by scrolling it off the
+    /// display, or reverse the direction of the scroll to cancel the dismissal.
+    case interactively
+
+    /// Never dismiss the keyboard automatically as a result of scrolling.
+    case never
+}

Sources/SwiftCrossUI/Views/Modifiers/ScrollDismissesKeyboardModifier.swift

@@ -0,0 +1,41 @@
+extension View {
+    /// Configures the behavior in which scrollable content interacts with
+    /// the software keyboard.
+    ///
+    /// You use this modifier to customize how scrollable content interacts
+    /// with the software keyboard. For example, you can specify a value of
+    /// ``ScrollDismissesKeyboardMode/immediately`` to indicate that you
+    /// would like scrollable content to immediately dismiss the keyboard if
+    /// present when a scroll drag gesture begins.
+    ///
+    ///     @State private var text = ""
+    ///
+    ///     ScrollView {
+    ///         TextField("Prompt", text: $text)
+    ///         ForEach(0 ..< 50) { index in
+    ///             Text("\(index)")
+    ///                 .padding()
+    ///         }
+    ///     }
+    ///     .scrollDismissesKeyboard(.immediately)
+    ///
+    /// You can also use this modifier to customize the keyboard dismissal
+    /// behavior for other kinds of scrollable views, like a ``List`` or a
+    /// ``TextEditor``.
+    ///
+    /// By default, scrollable content never automatically dismisses the keyboard.
+    /// Pass a different value of ``ScrollDismissesKeyboardMode`` to change this behavior.
+    /// For example, ``ScrollDismissesKeyboardMode/interactively`` allows the keyboard to dismiss
+    /// as the user scrolls. Note that ``TextEditor`` may still use a different
+    /// default to preserve expected editing behavior.
+    ///
+    /// - Parameter mode: The keyboard dismissal mode that scrollable content
+    ///   uses.
+    ///
+    /// - Returns: A view that uses the specified keyboard dismissal mode.
+    public func scrollDismissesKeyboard(_ mode: ScrollDismissesKeyboardMode) -> some View {
+        EnvironmentModifier(self) { environment in
+            environment.with(\.scrollDismissesKeyboardMode, mode)
+        }
+    }
+}

Sources/UIKitBackend/UIKitBackend+Control.swift

@@ -318,6 +318,16 @@ extension UIKitBackend {
                 textEditorWidget.child.inputAccessoryView = nil
             }
         #endif
+
+        textEditorWidget.child.alwaysBounceVertical = environment.scrollDismissesKeyboardMode != .never
+        textEditorWidget.child.keyboardDismissMode = switch environment.scrollDismissesKeyboardMode {
+        case .immediately:
+            textEditorWidget.child.inputAccessoryView == nil ? .onDrag : .onDragWithAccessory
+        case .interactively:
+            textEditorWidget.child.inputAccessoryView == nil ? .interactive : .interactiveWithAccessory
+        case .never:
+                .none
+        }
     }
 
     public func setContent(ofTextEditor textEditor: Widget, to content: String) {