Add View.textSelectionEnabled modifier (#220)

* removed files that were not supposed to exist

* Added UIKit & AppKit Text Selectability modifier

* Added GtkBackend Support

* winui support

* reintroduced numberOfLines = 0 in UIKitBackend

* implemented requested Changes

Additionally I changed the default value of isTextSelectionEnabled to be set in the initializer, where the other values get set. Should help to get an impression of the default values faster than setting it in the property definition.

* Added suggested AppKitBackend textSelection fix

* Make it run on tvOS, prefer beberkas solution on merge

textSelection is being ignored on tvOS

* Formatting changes

Author: MiaKoring

Examples/Sources/GreetingGeneratorExample/GreetingGeneratorApp.swift

@@ -10,6 +10,7 @@ import SwiftCrossUI
 struct GreetingGeneratorApp: App {
     @State var name = ""
     @State var greetings: [String] = []
+    @State var isGreetingSelectable = false
 
     var body: some Scene {
         WindowGroup("Greeting Generator") {
@@ -26,9 +27,11 @@ struct GreetingGeneratorApp: App {
                         }
                     }
 
+                    Toggle("Selectable Greeting", active: $isGreetingSelectable)
                     if let latest = greetings.last {
                         Text(latest)
                             .padding(.top, 5)
+                            .textSelectionEnabled(isGreetingSelectable)
 
                         if greetings.count > 1 {
                             Text("History:")

Sources/AppKitBackend/AppKitBackend.swift

@@ -573,6 +573,10 @@ public final class AppKitBackend: AppBackend {
     ) {
         let field = textView as! NSTextField
         field.attributedStringValue = Self.attributedString(for: content, in: environment)
+        if field.isSelectable && !environment.isTextSelectionEnabled {
+            field.abortEditing()
+        }
+        field.isSelectable = environment.isTextSelectionEnabled
     }
 
     public func createButton() -> Widget {

Sources/GtkBackend/GtkBackend.swift

@@ -606,7 +606,7 @@ public final class GtkBackend: AppBackend {
                 case .trailing:
                     Justification.right
             }
-
+        textView.selectable = environment.isTextSelectionEnabled
         textView.css.clear()
         textView.css.set(properties: Self.cssProperties(for: environment))
     }

Sources/SwiftCrossUI/Environment/EnvironmentValues.swift

@@ -95,6 +95,9 @@ public struct EnvironmentValues {
     /// The style of toggle to use.
     public var toggleStyle: ToggleStyle
 
+    /// Whether the text should be selectable. Set by ``View/textSelectionEnabled(_:)``.
+    public var isTextSelectionEnabled: Bool
+
     // Backing storage for extensible subscript
     private var extraValues: [ObjectIdentifier: Any]
 
@@ -208,6 +211,7 @@ public struct EnvironmentValues {
         toggleStyle = .button
         isEnabled = true
         scrollDismissesKeyboardMode = .automatic
+        isTextSelectionEnabled = false
     }
 
     /// Returns a copy of the environment with the specified property set to the

Sources/SwiftCrossUI/Views/ForEach.swift

@@ -28,7 +28,7 @@ extension ForEach where Items == [Int] {
         self.elements = Array(range)
         self.child = child
     }
-    
+
     /// Creates a view that creates child views on demand based on a given Range
     @_disfavoredOverload
     public init(

Sources/SwiftCrossUI/Views/Modifiers/TextSelectionModifier.swift

@@ -0,0 +1,10 @@
+extension View {
+    /// Set selectability of contained text. Ignored on tvOS.
+    public func textSelectionEnabled(_ isEnabled: Bool = true) -> some View {
+        EnvironmentModifier(
+            self,
+            modification: { environment in
+                environment.with(\.isTextSelectionEnabled, isEnabled)
+            })
+    }
+}

Sources/UIKitBackend/UIKitBackend+Control.swift

@@ -182,10 +182,8 @@ final class TappableWidget: ContainerWidget {
     }
 }
 
-@available(tvOS, unavailable)
-final class HoverableWidget: ContainerWidget {
-    // So much as attempting to reference UIHoverGestureRecognizer here results in a linker error on tvOS.
-    #if !os(tvOS)
+#if !os(tvOS)
+    final class HoverableWidget: ContainerWidget {
         private var hoverGestureRecognizer: UIHoverGestureRecognizer?
 
         var hoverChangesHandler: ((Bool) -> Void)? {
@@ -211,8 +209,8 @@ final class HoverableWidget: ContainerWidget {
                 default: break
             }
         }
-    #endif
-}
+    }
+#endif
 
 @available(tvOS, unavailable)
 final class SliderWidget: WrapperWidget<UISlider> {

Sources/UIKitBackend/UIKitBackend+Passive.swift

@@ -36,7 +36,7 @@ extension UIKitBackend {
     }
 
     public func createTextView() -> Widget {
-        let widget = WrapperWidget<UILabel>()
+        let widget = WrapperWidget<OptionallySelectableLabel>()
         widget.child.numberOfLines = 0
         return widget
     }
@@ -46,12 +46,13 @@ extension UIKitBackend {
         content: String,
         environment: EnvironmentValues
     ) {
-        let wrapper = textView as! WrapperWidget<UILabel>
+        let wrapper = textView as! WrapperWidget<OptionallySelectableLabel>
         wrapper.child.overrideUserInterfaceStyle = environment.colorScheme.userInterfaceStyle
         wrapper.child.attributedText = UIKitBackend.attributedString(
             text: content,
             environment: environment
         )
+        wrapper.child.isSelectable = environment.isTextSelectionEnabled
     }
 
     public func size(
@@ -104,3 +105,77 @@ extension UIKitBackend {
         wrapper.child.image = .init(ciImage: ciImage)
     }
 }
+
+// Inspired by https://medium.com/kinandcartacreated/making-uilabel-accessible-5f3d5c342df4
+// Thank you to Sam Dods for the base idea
+final class OptionallySelectableLabel: UILabel {
+    var isSelectable: Bool = false
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        setupTextSelection()
+    }
+
+    required init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        setupTextSelection()
+    }
+
+    override var canBecomeFirstResponder: Bool {
+        isSelectable
+    }
+
+    private func setupTextSelection() {
+        #if !os(tvOS)
+            let longPress = UILongPressGestureRecognizer(
+                target: self, action: #selector(didLongPress))
+            addGestureRecognizer(longPress)
+            isUserInteractionEnabled = true
+        #endif
+    }
+
+    @objc private func didLongPress(_ gesture: UILongPressGestureRecognizer) {
+        #if !os(tvOS)
+            guard
+                isSelectable,
+                gesture.state == .began,
+                let text = self.attributedText?.string,
+                !text.isEmpty
+            else {
+                return
+            }
+            window?.endEditing(true)
+            guard becomeFirstResponder() else { return }
+
+            let menu = UIMenuController.shared
+            if !menu.isMenuVisible {
+                menu.showMenu(from: self, rect: textRect())
+            }
+        #endif
+    }
+
+    override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
+        return action == #selector(copy(_:))
+    }
+
+    private func textRect() -> CGRect {
+        let inset: CGFloat = -4
+        return textRect(forBounds: bounds, limitedToNumberOfLines: numberOfLines)
+            .insetBy(dx: inset, dy: inset)
+    }
+
+    private func cancelSelection() {
+        #if !os(tvOS)
+            let menu = UIMenuController.shared
+            menu.hideMenu(from: self)
+        #endif
+    }
+
+    @objc override func copy(_ sender: Any?) {
+        #if !os(tvOS)
+            cancelSelection()
+            let board = UIPasteboard.general
+            board.string = text
+        #endif
+    }
+}

Sources/UIKitBackend/UIKitBackend+WebView.swift

@@ -1,5 +1,6 @@
-#if !os(tvOS)
-    import SwiftCrossUI
+import SwiftCrossUI
+
+#if canImport(WebKit)
     import WebKit
 
     extension UIKitBackend {

Sources/WinUIBackend/WinUIBackend.swift

@@ -578,6 +578,7 @@ public final class WinUIBackend: AppBackend {
     ) {
         let block = textView as! TextBlock
         block.text = content
+        block.isTextSelectionEnabled = environment.isTextSelectionEnabled
         missing("font design handling (monospace vs normal)")
         environment.apply(to: block)
     }