Added UIKit .onHover + minor consistency improvement | fixed minor Naming fixes in AppKitBackend

- tapGestureRecognizer and longPressGestureRecognizer now get removed if their corresponding handler is set to nil.
- Added Hoverable Widget
- Added hovertarget creation & update functions
- added macCalatalyst as compatible for UISlider since it supports it

Author: MiaKoring

Examples/Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 5.10
 
 import Foundation
 import PackageDescription

Sources/AppKitBackend/AppKitBackend.swift

@@ -1435,17 +1435,17 @@ public final class AppKitBackend: AppBackend {
             .isActive = true
         child.translatesAutoresizingMaskIntoConstraints = false
 
-        let tapGestureTarget = NSCustomHoverTarget()
-        container.addSubview(tapGestureTarget)
-        tapGestureTarget.leadingAnchor.constraint(equalTo: container.leadingAnchor)
+        let hoverGestureTarget = NSCustomHoverTarget()
+        container.addSubview(hoverGestureTarget)
+        hoverGestureTarget.leadingAnchor.constraint(equalTo: container.leadingAnchor)
             .isActive = true
-        tapGestureTarget.topAnchor.constraint(equalTo: container.topAnchor)
+        hoverGestureTarget.topAnchor.constraint(equalTo: container.topAnchor)
             .isActive = true
-        tapGestureTarget.trailingAnchor.constraint(equalTo: container.trailingAnchor)
+        hoverGestureTarget.trailingAnchor.constraint(equalTo: container.trailingAnchor)
             .isActive = true
-        tapGestureTarget.bottomAnchor.constraint(equalTo: container.bottomAnchor)
+        hoverGestureTarget.bottomAnchor.constraint(equalTo: container.bottomAnchor)
             .isActive = true
-        tapGestureTarget.translatesAutoresizingMaskIntoConstraints = false
+        hoverGestureTarget.translatesAutoresizingMaskIntoConstraints = false
 
         return container
     }
@@ -1455,8 +1455,8 @@ public final class AppKitBackend: AppBackend {
         environment: EnvironmentValues,
         action: @escaping (Bool) -> Void
     ) {
-        let tapGestureTarget = container.subviews[1] as! NSCustomHoverTarget
-        tapGestureTarget.hoverChangesHandler = action
+        let hoverGestureTarget = container.subviews[1] as! NSCustomHoverTarget
+        hoverGestureTarget.hoverChangesHandler = action
     }
 
     final class NSBezierPathView: NSView {
@@ -1773,6 +1773,8 @@ final class NSCustomHoverTarget: NSView {
                 addTrackingArea(area)
                 trackingArea = area
             } else if hoverChangesHandler == nil, let trackingArea {
+                // should be impossible at the moment of implementation
+                // keeping it to be save in case of later changes
                 removeTrackingArea(trackingArea)
                 self.trackingArea = nil
             }

Sources/UIKitBackend/UIKitBackend+Control.swift

@@ -133,6 +133,9 @@ final class TappableWidget: ContainerWidget {
                     target: self, action: #selector(viewTouched))
                 child.view.addGestureRecognizer(gestureRecognizer)
                 self.tapGestureRecognizer = gestureRecognizer
+            } else if onTap == nil, let tapGestureRecognizer {
+                child.view.removeGestureRecognizer(tapGestureRecognizer)
+                self.tapGestureRecognizer = nil
             }
         }
     }
@@ -144,6 +147,9 @@ final class TappableWidget: ContainerWidget {
                     target: self, action: #selector(viewLongPressed(sender:)))
                 child.view.addGestureRecognizer(gestureRecognizer)
                 self.longPressGestureRecognizer = gestureRecognizer
+            } else if onLongPress == nil, let longPressGestureRecognizer {
+                child.view.removeGestureRecognizer(longPressGestureRecognizer)
+                self.onLongPress = nil
             }
         }
     }
@@ -164,6 +170,36 @@ final class TappableWidget: ContainerWidget {
     }
 }
 
+
+@available(tvOS, unavailable)
+final class HoverableWidget: ContainerWidget {
+    private var hoverGestureRecognizer: UIHoverGestureRecognizer?
+
+    var hoverChangesHandler: ((Bool) -> Void)? {
+        didSet {
+            if hoverChangesHandler != nil && hoverGestureRecognizer == nil {
+                let gestureRecognizer = UIHoverGestureRecognizer(target: self,
+                                                                 action: #selector(hoveringChanged(_:)))
+                child.view.addGestureRecognizer(gestureRecognizer)
+                self.hoverGestureRecognizer = gestureRecognizer
+            } else if hoverChangesHandler == nil, let hoverGestureRecognizer {
+                // should be impossible at the moment of implementation
+                // keeping it to be save in case of later changes
+                child.view.removeGestureRecognizer(hoverGestureRecognizer)
+                self.hoverGestureRecognizer = nil
+            }
+        }
+    }
+
+    @objc
+    func hoveringChanged(_ recognizer: UIHoverGestureRecognizer) {
+        switch recognizer.state {
+        case .began: hoverChangesHandler?(true)
+        case .ended: hoverChangesHandler?(false)
+        default: break
+        }
+    }
+}
 @available(tvOS, unavailable)
 final class SliderWidget: WrapperWidget<UISlider> {
     var onChange: ((Double) -> Void)?
@@ -413,8 +449,19 @@ extension UIKitBackend {
                 wrapper.onLongPress = environment.isEnabled ? action : {}
         }
     }
+    
+    public func createHoverTarget(wrapping child: Widget) -> Widget {
+        HoverableWidget(child: child)
+    }
+    
+    public func updateHoverTarget(_ hoverTarget: any WidgetProtocol,
+                                  environment: EnvironmentValues,
+                                  action: @escaping (Bool) -> Void) {
+        let wrapper = hoverTarget as! HoverableWidget
+        wrapper.hoverChangesHandler = action
+    }
 
-    #if os(iOS) || os(visionOS)
+    #if os(iOS) || os(visionOS) || targetEnvironment(macCatalyst)
         public func createSlider() -> Widget {
             SliderWidget()
         }