Add ignoresKeyboard option (#18)

Co-authored-by: Muukii <[email protected]>

Development/Development/ContentView.swift

@@ -6,13 +6,23 @@
 //
 
 import SwiftUI
+import SwiftUIHosting
 
 struct ContentView: View {
   var body: some View {
     NavigationView {
       List {        
         NavigationLink("Content") {
-          BookSizing()
+          BookSizing()          
+        }
+        NavigationLink("Keyboard Avoidance ignores") {
+          KeyboardAvoidanceViewControllerRepresentable(ignoresKeyboard: true)
+            .edgesIgnoringSafeArea(.all)
+        }
+
+        NavigationLink("Keyboard Avoidance not ignores") {
+          KeyboardAvoidanceViewControllerRepresentable(ignoresKeyboard: false)
+            .edgesIgnoringSafeArea(.all)
         }
       }
     }
@@ -25,3 +35,70 @@ struct ContentView_Previews: PreviewProvider {
   }
 }
 
+struct KeyboardAvoidanceViewControllerRepresentable: UIViewControllerRepresentable {
+
+  let ignoresKeyboard: Bool
+
+  init(ignoresKeyboard: Bool) {
+    self.ignoresKeyboard = ignoresKeyboard
+  }
+
+  func makeUIViewController(context: Context) -> some UIViewController {
+    KeyboardAvoidanceViewController(ignoresKeyboard: ignoresKeyboard)
+  }
+
+  func updateUIViewController(_ uiViewController: UIViewControllerType, context: Context) {
+
+  }
+
+}
+
+final class KeyboardAvoidanceViewController: UIViewController, UITextFieldDelegate {
+
+  let ignoresKeyboard: Bool
+
+  init(ignoresKeyboard: Bool) {
+    self.ignoresKeyboard = ignoresKeyboard
+    super.init(nibName: nil, bundle: nil)
+  }
+
+  required init?(coder: NSCoder) {
+    fatalError()
+  }
+
+  override func viewDidLoad() {
+    super.viewDidLoad()
+
+    let hostingView = SwiftUIHostingView(configuration: .init(ignoresKeyboard: ignoresKeyboard)) { 
+      Text("Hello")
+    }
+
+    view.addSubview(hostingView)
+    hostingView.translatesAutoresizingMaskIntoConstraints = false
+
+    NSLayoutConstraint.activate([
+      hostingView.rightAnchor.constraint(equalTo: view.rightAnchor),
+      hostingView.bottomAnchor
+        .constraint(equalTo: view.bottomAnchor, constant: -200),
+      hostingView.leftAnchor.constraint(equalTo: view.leftAnchor),
+    ])
+
+    let textField = UITextField()
+    textField.borderStyle = .roundedRect
+    textField.delegate = self
+
+    textField.translatesAutoresizingMaskIntoConstraints = false
+    view.addSubview(textField)
+
+    NSLayoutConstraint.activate([
+      textField.topAnchor.constraint(equalTo: view.topAnchor, constant: 100),
+      textField.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+    ])
+  }
+
+  func textFieldShouldReturn(_ textField: UITextField) -> Bool {
+    textField.resignFirstResponder()
+    return true
+  }
+
+}

Sources/SwiftUIHosting/HostingController.swift

@@ -10,6 +10,7 @@ final class HostingController<Content: View>: UIHostingController<Content> {
   init(
     accessibilityIdentifier: String? = nil,
     disableSafeArea: Bool,
+    ignoresKeyboard: Bool,
     rootView: Content
   ) {
 
@@ -20,6 +21,33 @@ final class HostingController<Content: View>: UIHostingController<Content> {
     // waiting for iOS 16.4 as minimum deployment target
     _disableSafeArea = disableSafeArea
 
+    // https://steipete.com/posts/disabling-keyboard-avoidance-in-swiftui-uihostingcontroller/
+    if ignoresKeyboard {
+      guard let viewClass = object_getClass(view) else { return }
+
+      let viewSubclassName = String(cString: class_getName(viewClass)).appending("_IgnoresKeyboard")
+      if let viewSubclass = NSClassFromString(viewSubclassName) {
+        object_setClass(view, viewSubclass)
+      }
+      else {
+        guard let viewClassNameUtf8 = (viewSubclassName as NSString).utf8String else { return }
+        guard let viewSubclass = objc_allocateClassPair(viewClass, viewClassNameUtf8, 0) else { return }
+
+        if let method = class_getInstanceMethod(viewClass, NSSelectorFromString("keyboardWillShowWithNotification:")) {
+          let keyboardWillShow: @convention(block) (AnyObject, AnyObject) -> Void = { _, _ in
+            if ignoresKeyboard {
+
+            } else {
+
+            }
+          }
+          class_addMethod(viewSubclass, NSSelectorFromString("keyboardWillShowWithNotification:"),
+                          imp_implementationWithBlock(keyboardWillShow), method_getTypeEncoding(method))
+        }
+        objc_registerClassPair(viewSubclass)
+        object_setClass(view, viewSubclass)
+      }
+    }
   }
 
   @MainActor required dynamic init?(coder aDecoder: NSCoder) {

Sources/SwiftUIHosting/SwiftUIHostingView.swift

@@ -25,13 +25,15 @@ open class SwiftUIHostingView<Content: View>: UIView {
       self.hostingController = HostingController(
         accessibilityIdentifier: _typeName(Content.self),
         disableSafeArea: configuration.disableSafeArea,
+        ignoresKeyboard: configuration.ignoresKeyboard,
         rootView: usingContent
       )
 
     #else
 
       self.hostingController = HostingController(
         disableSafeArea: configuration.disableSafeArea,
+        ignoresKeyboard: configuration.ignoresKeyboard,
         rootView: usingContent
       )
 
@@ -231,18 +233,22 @@ public struct SwiftUIHostingConfiguration {
    */
   public var disableSafeArea: Bool
 
+  public var ignoresKeyboard: Bool
+
   public var sizeMeasureMode: SwiftUIHostingSizeMeasureMode
 
   public var baseModifier: BaseModifier
 
   public init(
     registersAsChildViewController: Bool = true,
     disableSafeArea: Bool = true,
+    ignoresKeyboard: Bool = false,
     sizeMeasureMode: SwiftUIHostingSizeMeasureMode = .systemSizeThatFits,
     baseModifier: BaseModifier = .shared
   ) {
     self.registersAsChildViewController = registersAsChildViewController
     self.disableSafeArea = disableSafeArea
+    self.ignoresKeyboard = ignoresKeyboard
     self.sizeMeasureMode = sizeMeasureMode
     self.baseModifier = baseModifier
   }