Update KeyboardSupport (#157)

Sources/FluidInterfaceKit-Demo/DemoKeyboardGuideViewController.swift

@@ -48,7 +48,8 @@ final class DemoKeyboardGuideViewController: UIViewController {
       .padding(.bottom, 200)
     }
 
-    scrollView.enableTrackingKeyboard()
+    scrollView.setContentInsetAdjustmentForKeyboard(isActive: true)
+    scrollView.setKeyboardSwipeDownOffscreenGesture(isActive: true)
   }
 
   private var observation: KeyboardObservation?

Sources/FluidKeyboardSupport/KeyboardFrameInfo.swift

@@ -0,0 +1,10 @@
+import Foundation
+import CoreGraphics
+
+public struct KeyboardFrameInfo: Equatable, Sendable {
+  public var height: CGFloat
+
+  init(height: CGFloat) {
+    self.height = height
+  }
+}

Sources/FluidKeyboardSupport/KeyboardObservation.swift

@@ -0,0 +1,17 @@
+import Foundation
+
+public final class KeyboardObservation {
+
+  private var keyValueObservation: NSKeyValueObservation
+  private let onInvalidate: () -> Void
+
+  init(keyValueObservation: NSKeyValueObservation, onInvalidate: @escaping () -> Void) {
+    self.keyValueObservation = keyValueObservation
+    self.onInvalidate = onInvalidate
+  }
+
+  deinit {
+    keyValueObservation.invalidate()
+  onInvalidate()
+  }
+}

Sources/FluidKeyboardSupport/UIScrollView+HidingKeyboard.swift

@@ -0,0 +1,86 @@
+import UIKit
+
+fileprivate var ref: Void?
+
+extension UIScrollView {
+
+  /**
+   The pan gesture tracks the location to determine whether it is on or off the keyboard.
+   When the location falls within the keyboard's boundaries, it hides the keyboard.
+   */
+  @available(iOS 15, *)
+  @MainActor
+  public func setKeyboardSwipeDownOffscreenGesture(isActive: Bool) {
+    if isActive {
+      let newCoordinator = PanGestureCoordinator(scrollView: self, panGesture: UIPanGestureRecognizer())
+      self.coordinator = newCoordinator
+    } else {
+      self.coordinator = nil
+    }
+  }
+
+  @available(iOS 15, *)
+  @MainActor
+  private var coordinator: PanGestureCoordinator? {
+    get { objc_getAssociatedObject(self, &ref) as? PanGestureCoordinator }
+    set { objc_setAssociatedObject(self, &ref, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC) }
+  }
+
+}
+
+@available(iOS 15, *)
+@MainActor
+private final class PanGestureCoordinator: NSObject, UIGestureRecognizerDelegate {
+
+  private let scrollView: UIScrollView
+  private let panGesture: UIPanGestureRecognizer
+
+  init(scrollView: UIScrollView, panGesture: UIPanGestureRecognizer) {
+    self.scrollView = scrollView
+    self.panGesture = panGesture
+    super.init()
+    panGesture.delegate = self
+    panGesture.addTarget(self, action: #selector(handlePanGesture(_:)))
+
+    scrollView.addGestureRecognizer(panGesture)
+  }
+
+  deinit {
+    Task { @MainActor [scrollView, panGesture] in
+      scrollView.removeGestureRecognizer(panGesture)
+    }
+  }
+
+  @objc private func handlePanGesture(_ gesture: UIPanGestureRecognizer) {
+
+    guard let view = gesture.view else {
+      assertionFailure()
+      return
+    }
+
+    let location = gesture.location(in: view)
+
+    switch gesture.state {
+    case .began, .changed:
+
+      if location.y > view.keyboardLayoutGuide.layoutFrame.minY {
+        view.endEditing(true)
+      }
+
+    case .ended:
+      break
+    default:
+      break
+    }
+
+  }
+
+  func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+    return true
+  }
+
+  func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
+    return true
+  }
+
+}

Sources/FluidKeyboardSupport/UIScrollView+TrackingKeyboard.swift

@@ -0,0 +1,73 @@
+import UIKit
+
+@MainActor
+private var ref: Void?
+
+extension UIScrollView {
+
+  @available(iOS 15, *)
+  private func _observeKeyboard(handler: @escaping @MainActor (KeyboardFrameInfo) -> Void) -> KeyboardObservation {
+
+    let dummyView = UIView()
+    dummyView.accessibilityIdentifier = "keyboard-dummy-view"
+
+    addSubview(dummyView)
+    dummyView.isUserInteractionEnabled = false
+    dummyView.isHidden = true
+    dummyView.translatesAutoresizingMaskIntoConstraints = false
+
+    NSLayoutConstraint.activate([
+      dummyView.topAnchor.constraint(equalTo: keyboardLayoutGuide.topAnchor),
+      dummyView.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor),
+      dummyView.leadingAnchor.constraint(equalTo: frameLayoutGuide.leadingAnchor),
+      dummyView.trailingAnchor.constraint(equalTo: frameLayoutGuide.trailingAnchor),
+    ])
+
+    let token = dummyView.observe(\.bounds) { @MainActor view, _ in
+      handler(.init(height: view.bounds.height))
+    }
+
+    return .init(keyValueObservation: token) { [weak dummyView] in
+      Task { @MainActor in
+        dummyView?.removeFromSuperview()
+      }
+    }
+
+  }
+
+  /**
+   It tracks the keyboard frame to set the content inset to prevent from hiding the view behind the keyboard.
+   */
+  @available(iOS 15, *)
+  @MainActor
+  public func setContentInsetAdjustmentForKeyboard(isActive: Bool) {
+
+    if isActive {
+
+      guard keyboardObservation == nil else { return }
+
+      keyboardObservation = self._observeKeyboard { [weak self] info in
+
+        guard let self else { return }
+
+        self.contentInset.bottom = info.height
+
+      }
+    } else {
+      keyboardObservation = nil
+    }
+
+  }
+
+  @MainActor
+  private var keyboardObservation: KeyboardObservation? {
+    get {
+      objc_getAssociatedObject(self, &ref) as? KeyboardObservation
+    }
+    set {
+      objc_setAssociatedObject(self, &ref, newValue, .OBJC_ASSOCIATION_RETAIN)
+    }
+  }
+
+
+}

Sources/FluidKeyboardSupport/UIView+TrackingKeyboard.swift

@@ -0,0 +1,37 @@
+
+import UIKit
+
+extension UIView {
+
+  @available(iOS 15, *)
+  public func observeKeyboard(handler: @escaping @MainActor (KeyboardFrameInfo) -> Void) -> KeyboardObservation {
+
+    let dummyView = UIView()
+    dummyView.accessibilityIdentifier = "keyboard-dummy-view"
+
+    addSubview(dummyView)
+    dummyView.isUserInteractionEnabled = false
+    dummyView.isHidden = true
+    dummyView.translatesAutoresizingMaskIntoConstraints = false
+
+    NSLayoutConstraint.activate([
+      dummyView.topAnchor.constraint(equalTo: keyboardLayoutGuide.topAnchor),
+      dummyView.bottomAnchor.constraint(equalTo: bottomAnchor),
+      dummyView.leadingAnchor.constraint(equalTo: leadingAnchor),
+      dummyView.trailingAnchor.constraint(equalTo: trailingAnchor),
+    ])
+
+    let token = dummyView.observe(\.bounds) { @MainActor view, _ in
+      handler(.init(height: view.bounds.height))
+    }
+
+    return .init(keyValueObservation: token) { [weak dummyView] in
+      Task { @MainActor in
+        dummyView?.removeFromSuperview()
+      }
+    }
+
+  }
+
+}
+