Initial implementation

Package.swift

@@ -1,28 +1,15 @@
-// swift-tools-version: 5.6
-// The swift-tools-version declares the minimum version of Swift required to build this package.
+// swift-tools-version:5.1
 
 import PackageDescription
 
 let package = Package(
     name: "FullScreenOverlay",
+    platforms: [.iOS(.v13), .macOS(.v10_15), .tvOS(.v13), .watchOS(.v6)],
     products: [
-        // Products define the executables and libraries a package produces, and make them visible to other packages.
-        .library(
-            name: "FullScreenOverlay",
-            targets: ["FullScreenOverlay"]),
-    ],
-    dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        // .package(url: /* package url */, from: "1.0.0"),
+        .library(name: "FullScreenOverlay", targets: ["FullScreenOverlay", "Previews"])
     ],
     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: "FullScreenOverlay",
-            dependencies: []),
-        .testTarget(
-            name: "FullScreenOverlayTests",
-            dependencies: ["FullScreenOverlay"]),
+        .target(name: "FullScreenOverlay", dependencies: []),
+        .target(name: "Previews", dependencies: ["FullScreenOverlay"])
     ]
 )

Sources/FullScreenOverlay/FullScreenOverlayContainer.swift

@@ -0,0 +1,17 @@
+import SwiftUI
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+class FullScreenOverlayContainer: ObservableObject {
+
+    static let shared: FullScreenOverlayContainer = .init()
+
+    @Published private(set) var overlays: [PresentationSpace: [AnyHashable: AnyView]] = .init()
+
+    func updateOverlay<ID: Hashable, Overlay: View>(_ overlay: Overlay, for id: ID, in presentationSpace: PresentationSpace) {
+        self.overlays[presentationSpace, default: [:]].updateValue(AnyView(overlay), forKey: id)
+    }
+
+    func removeOverlay<ID: Hashable>(for id: ID, in presentationSpace: PresentationSpace) {
+        self.overlays[presentationSpace, default: [:]].removeValue(forKey: id)
+    }
+}

Sources/FullScreenOverlay/FullScreenOverlayPresenter.swift

@@ -0,0 +1,22 @@
+import SwiftUI
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+struct FullScreenOverlayPresenter: ViewModifier {
+
+    var presentationSpace: PresentationSpace
+
+    @ObservedObject private var container: FullScreenOverlayContainer = .shared
+
+    func body(content: Content) -> some View {
+        content.overlay(
+            ZStack {
+                ForEach(
+                    container.overlays[presentationSpace, default: [:]].sorted(by: { $0.key.hashValue < $1.key.hashValue }),
+                    id: \.key
+                ) { _, overlay in
+                    overlay
+                }
+            }
+        )
+    }
+}

Sources/FullScreenOverlay/FullScreenOverlaySetter.swift

@@ -0,0 +1,38 @@
+import SwiftUI
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+struct FullScreenOverlaySetter<Overlay: View>: ViewModifier {
+
+    var overlay: Overlay
+    var presentationSpace: PresentationSpace
+
+    @State private var id: UUID = .init()
+    @State private var isAppearing: Bool = false
+
+    func body(content: Content) -> some View {
+        return content
+            .onAppear { isAppearing = true; updateOverlay() }
+            .onDisappear { isAppearing = false; removeOverlay() }
+            .onUpdate { isAppearing ? updateOverlay() : removeOverlay() }
+        // onDisappear 이후에 onUpdate가 실행되는 경우도 있기 때문에, isAppearing 상태를 저장해 오버레이가 다시 추가되는 것을 방지한다.
+    }
+
+    private func updateOverlay() {
+        FullScreenOverlayContainer.shared.updateOverlay(overlay, for: id, in: presentationSpace)
+    }
+
+    private func removeOverlay() {
+        FullScreenOverlayContainer.shared.removeOverlay(for: id, in: presentationSpace)
+    }
+}
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+private extension View {
+
+    func onUpdate(perform action: (() -> Void)? = nil) -> some View {
+        if let action = action {
+            DispatchQueue.main.async(execute: action)
+        }
+        return self
+    }
+}

Sources/FullScreenOverlay/PresentationSpace.swift

@@ -0,0 +1,6 @@
+import SwiftUI
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+public enum PresentationSpace: Equatable, Hashable {
+    case named(AnyHashable)
+}

Sources/FullScreenOverlay/View+FullScreenOverlay.swift

@@ -0,0 +1,17 @@
+import SwiftUI
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+public extension View {
+
+    func fullScreenOverlayPresentationSpace<T: Hashable>(name: T) -> some View {
+        self
+            .modifier(FullScreenOverlayPresenter(presentationSpace: .named(name)))
+    }
+
+    @ViewBuilder func fullScreenOverlay<Overlay: View>(
+        presentationSpace: PresentationSpace,
+        @ViewBuilder content: () -> Overlay
+    ) -> some View {
+        self.modifier(FullScreenOverlaySetter(overlay: content(), presentationSpace: presentationSpace))
+    }
+}

Sources/Previews/Previews.swift

@@ -0,0 +1,63 @@
+import SwiftUI
+import FullScreenOverlay
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+private struct RootView: View {
+
+    @State private var isPresentingBottomSheet: Bool = false
+
+    var body: some View {
+        List {
+            Button(
+                "Present Bottom Sheet",
+                action: { isPresentingBottomSheet = true }
+            )
+            .fullScreenOverlay(presentationSpace: .named("RootView")) {
+                if isPresentingBottomSheet {
+                    BottomSheet(onDismiss: { isPresentingBottomSheet = false })
+                }
+            }
+        }
+    }
+}
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+private struct BottomSheet: View {
+
+    var onDismiss: () -> Void
+
+    @State private var isAppearing: Bool = false
+
+    var body: some View {
+        Color.black.opacity(0.2)
+            .edgesIgnoringSafeArea(.all)
+            .zIndex(-1)
+            .onTapGesture(perform: onDismiss)
+            .transition(.opacity.animation(.default))
+        VStack {
+            Text("Bottom Sheet")
+                .font(.title.weight(.semibold))
+                .padding(.vertical, 128)
+            Button("Dismiss", action: { isAppearing = false; onDismiss() })
+        }
+        .padding(.vertical, 32)
+        .frame(maxWidth: .infinity)
+        .background(
+            Color.white
+                .shadow(radius: 1)
+                .edgesIgnoringSafeArea(.all)
+        )
+        .frame(maxHeight: .infinity, alignment: .bottom)
+        .transition(.move(edge: .bottom))
+        .animation(.spring())
+    }
+}
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+internal struct SwiftUIView_Previews: PreviewProvider {
+
+    static var previews: some View {
+        RootView()
+            .fullScreenOverlayPresentationSpace(name: "RootView")
+    }
+}