Init

.gitignore

@@ -0,0 +1,9 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj
+xcuserdata/
+DerivedData/
+.swiftpm/config/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

.swiftpm/xcode/package.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

Package.swift

@@ -0,0 +1,32 @@
+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+  name: "SwiftUIHosting",
+  platforms: [.iOS(.v13)],
+  products: [
+    // Products define the executables and libraries a package produces, and make them visible to other packages.
+    .library(
+      name: "SwiftUIHosting",
+      targets: ["SwiftUIHosting"]
+    )
+  ],
+  dependencies: [
+    // Dependencies declare other packages that this package depends on.
+    // .package(url: /* package url */, from: "1.0.0"),
+  ],
+  targets: [
+    // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+    // Targets can depend on other targets in this package, and on products in packages this package depends on.
+    .target(
+      name: "SwiftUIHosting",
+      dependencies: []
+    ),
+    .testTarget(
+      name: "SwiftUIHostingTests",
+      dependencies: ["SwiftUIHosting"]
+    ),
+  ]
+)

README.md

@@ -1 +1,3 @@
+# MyLibrary
 
+A description of this package.

Sources/SwiftUIHosting/HostingController.swift

@@ -0,0 +1,82 @@
+import SwiftUI
+
+@available(iOS 13, *)
+final class HostingController<Content: View>: UIHostingController<Content> {
+
+  var onViewDidLayoutSubviews: (UIViewController) -> Void = { _ in }
+
+  init(disableSafeArea: Bool, rootView: Content) {
+    super.init(rootView: rootView)
+
+    // https://www.notion.so/muukii/UIHostingController-safeArea-issue-ec66a560970c4a1cb44f21cc448bc513?pvs=4
+#if USE_SWIZZLING
+    _ = _once_
+    _fixing_safeArea = disableSafeArea
+#else
+    _disableSafeArea = disableSafeArea
+#endif
+  }
+
+  @MainActor required dynamic init?(coder aDecoder: NSCoder) {
+    fatalError("init(coder:) has not been implemented")
+  }
+
+  override func viewDidLayoutSubviews() {
+    super.viewDidLayoutSubviews()
+
+    onViewDidLayoutSubviews(self)
+  }
+}
+
+#if USE_SWIZZLING
+
+private let _once_: Void = {
+  UIView.replace()
+}()
+
+private var _key: Void?
+
+extension UIView {
+
+  fileprivate static func replace() {
+
+    method_exchangeImplementations(
+      class_getInstanceMethod(self, #selector(getter:UIView.safeAreaInsets))!,
+      class_getInstanceMethod(self, #selector(getter:UIView._hosting_safeAreaInsets))!
+    )
+
+    method_exchangeImplementations(
+      class_getInstanceMethod(self, #selector(getter:UIView.safeAreaLayoutGuide))!,
+      class_getInstanceMethod(self, #selector(getter:UIView._hosting_safeAreaLayoutGuide))!
+    )
+
+  }
+
+  fileprivate var _fixing_safeArea: Bool {
+    get {
+      (objc_getAssociatedObject(self, &_key) as? Bool) ?? false
+    }
+    set {
+      objc_setAssociatedObject(self, &_key, newValue, .OBJC_ASSOCIATION_COPY_NONATOMIC)
+    }
+  }
+
+  @objc dynamic var _hosting_safeAreaInsets: UIEdgeInsets {
+    if _fixing_safeArea {
+      return .zero
+    } else {
+      return self._hosting_safeAreaInsets
+    }
+  }
+
+  @objc dynamic var _hosting_safeAreaLayoutGuide: UILayoutGuide? {
+    if _fixing_safeArea {
+      return nil
+    } else {
+     return self._hosting_safeAreaLayoutGuide
+    }
+  }
+
+}
+
+#endif

Sources/SwiftUIHosting/SwiftUIHostingView.swift

@@ -0,0 +1,167 @@
+import SwiftUI
+
+/// A view that hosts SwiftUI for UIKit environment.
+open class SwiftUIHostingView: UIView {
+
+  public struct Configuration {
+
+    /**
+     Registers internal hosting controller into the nearest view controller's children.
+
+     Apple developer explains why we need to UIHostinController should be a child of the view controller.
+     ```
+     When using UIHostingController, make sure to always add the view controller together with the view to your app.
+
+     Many SwiftUI features, such as toolbars, keyboard shortcuts, and views that use UIViewControllerRepresentable, require a connection to the view controller hierarchy in UIKit to integrate properly, so never separate a hosting controller's view from the hosting controller itself.
+     ```
+     */
+    public var registersAsChildViewController: Bool
+
+    /**
+     Fixes handling safe area issue
+     https://www.notion.so/muukii/UIHostingController-safeArea-issue-ec66a560970c4a1cb44f21cc448bc513?pvs=4
+     */
+    public var disableSafeArea: Bool
+
+    public init(
+      registersAsChildViewController: Bool = true,
+      disableSafeArea: Bool = true
+    ) {
+      self.registersAsChildViewController = registersAsChildViewController
+      self.disableSafeArea = disableSafeArea
+    }
+  }
+
+  private var hostingController: HostingController<RootView>
+
+  private let proxy: Proxy = .init()
+
+  public let configuration: Configuration
+
+  public convenience init<Content: View>(
+    _ name: String = "",
+    _ file: StaticString = #file,
+    _ function: StaticString = #function,
+    _ line: UInt = #line,
+    configuration: Configuration = .init(),
+    @ViewBuilder content: @escaping () -> Content
+  ) {
+    self.init(
+      name,
+      file,
+      function,
+      line,
+      configuration: configuration
+    )
+    setContent(content: content)
+  }
+
+  // MARK: - Initializers
+
+  public init(
+    _ name: String = "",
+    _ file: StaticString = #file,
+    _ function: StaticString = #function,
+    _ line: UInt = #line,
+    configuration: Configuration = .init()
+  ) {
+    self.configuration = configuration
+
+    self.hostingController = HostingController(
+      disableSafeArea: configuration.disableSafeArea,
+      rootView: RootView(proxy: proxy)
+    )
+
+    super.init(frame: .null)
+
+    #if DEBUG
+    let file = URL(string: file.description)?.deletingPathExtension().lastPathComponent ?? "unknown"
+    self.accessibilityIdentifier = [
+      name,
+      file,
+      function.description,
+      line.description,
+    ]
+    .joined(separator: ".")
+    #endif
+
+    hostingController.view.backgroundColor = .clear
+
+    addSubview(hostingController.view)
+    hostingController.view.translatesAutoresizingMaskIntoConstraints = false
+
+    NSLayoutConstraint.activate([
+      hostingController.view.topAnchor.constraint(equalTo: topAnchor),
+      hostingController.view.rightAnchor.constraint(equalTo: rightAnchor),
+      hostingController.view.bottomAnchor.constraint(equalTo: bottomAnchor),
+      hostingController.view.leftAnchor.constraint(equalTo: leftAnchor),
+    ])
+
+    hostingController.onViewDidLayoutSubviews = { controller in
+      // TODO: Reduces number of calling invalidation, it's going to be happen even it's same value.
+      controller.view.invalidateIntrinsicContentSize()
+    }
+
+  }
+
+  @available(*, unavailable)
+  public required init?(coder: NSCoder) {
+    fatalError("init(coder:) has not been implemented")
+  }
+
+  // MARK: UIView
+
+  /// Returns calculated size using internal hosting controller
+  open override func sizeThatFits(_ size: CGSize) -> CGSize {
+    hostingController.sizeThatFits(in: size)
+  }
+
+  open override func didMoveToWindow() {
+
+    super.didMoveToWindow()
+
+    if configuration.registersAsChildViewController {
+      // https://muukii.notion.site/Why-we-need-to-add-UIHostingController-to-view-controller-chain-14de20041c99499d803f5a877c9a1dd1
+
+      if let _ = window {
+        if let parentViewController = self.findNearestViewController() {
+          parentViewController.addChild(hostingController)
+          hostingController.didMove(toParent: parentViewController)
+        } else {
+          assertionFailure()
+        }
+      } else {
+        hostingController.willMove(toParent: nil)
+        hostingController.removeFromParent()
+      }
+    }
+  }
+
+  // MARK: -
+
+  public final func setContent<Content: SwiftUI.View>(
+    @ViewBuilder content: @escaping () -> Content
+  ) {
+    proxy.content = {
+      return SwiftUI.AnyView(
+        content()
+      )
+    }
+  }
+
+}
+
+final class Proxy: ObservableObject {
+  @Published var content: () -> SwiftUI.AnyView? = { nil }
+
+  init() {
+  }
+}
+
+struct RootView: SwiftUI.View {
+  @ObservedObject var proxy: Proxy
+
+  var body: some View {
+    proxy.content()
+  }
+}

Sources/SwiftUIHosting/UIResponder+.swift

@@ -0,0 +1,12 @@
+import UIKit
+
+extension UIResponder {
+
+  func findNearestViewController() -> UIViewController? {
+    sequence(first: self, next: { $0.next })
+      .first {
+        $0 is UIViewController
+      } as? UIViewController
+  }
+
+}

Tests/SwiftUIHostingTests/MyLibraryTests.swift

@@ -0,0 +1 @@
+