Add Async image loading

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/AppDelegate.swift

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+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+The application delegate.
+*/
+
+import UIKit
+
+@UIApplicationMain
+class AppDelegate: UIResponder, UIApplicationDelegate {
+
+    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
+        // Override point for customization after application launch.
+        return true
+    }
+
+    func applicationWillTerminate(_ application: UIApplication) {
+        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
+    }
+
+    // MARK: UISceneSession Lifecycle
+    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
+        // Called when a new scene session is being created.
+        // Use this method to select a configuration to create the new scene with.
+        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
+    }
+
+    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
+        // Called when the user discards a scene session.
+        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
+        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
+    }
+
+}
+

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Assets.xcassets/AppIcon.appiconset/Contents.json

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+{
+  "images" : [
+    {
+      "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_40x40.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "3x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_58x58.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_87x87.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_80x80.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_120x120.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_120x120-1.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "landmark_app_icon_180x180.png",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "1x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_40x40-1.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "29x29",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_58x58-1.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_40x40-2.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_80x80-1.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "76x76",
+      "scale" : "1x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_152x152.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "83.5x83.5",
+      "idiom" : "ipad",
+      "filename" : "landmark_app_icon_167x167.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "1024x1024",
+      "idiom" : "ios-marketing",
+      "filename" : "landmark_app_icon_1024x1024.png",
+      "scale" : "1x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Assets.xcassets/turtlerock.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "turtlerock.jpg",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Base.lproj/LaunchScreen.storyboard

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13122.16" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13104.12"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" xcode11CocoaTouchSystemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
+                        <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+</document>

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Info.plist

@@ -0,0 +1,62 @@
+<?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>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>$(PRODUCT_BUNDLE_PACKAGE_TYPE)</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UIApplicationSceneManifest</key>
+	<dict>
+		<key>UIApplicationSupportsMultipleScenes</key>
+		<false/>
+		<key>UISceneConfigurations</key>
+		<dict>
+			<key>UIWindowSceneSessionRoleApplication</key>
+			<array>
+				<dict>
+					<key>UILaunchStoryboardName</key>
+					<string>LaunchScreen</string>
+					<key>UISceneConfigurationName</key>
+					<string>Default Configuration</string>
+					<key>UISceneDelegateClassName</key>
+					<string>$(PRODUCT_MODULE_NAME).SceneDelegate</string>
+				</dict>
+			</array>
+		</dict>
+	</dict>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>armv7</string>
+	</array>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+</dict>
+</plist>

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/LandmarkDetail.swift

@@ -0,0 +1,48 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+A view showing the details for a landmark.
+*/
+
+import SwiftUI
+
+struct LandmarkDetail: View {
+    var landmark: Landmark
+
+    var body: some View {
+        VStack {
+            MapView(coordinate: landmark.locationCoordinate)
+                .frame(height: 300)
+
+            CircleImage(image: landmark.image(forSize: 250))
+                .offset(x: 0, y: -130)
+                .padding(.bottom, -130)
+
+            VStack(alignment: .leading) {
+                Text(landmark.name)
+                    .font(.title)
+
+                HStack(alignment: .top) {
+                    Text(landmark.park)
+                        .font(.subheadline)
+                    Spacer()
+                    Text(landmark.state)
+                        .font(.subheadline)
+                }
+            }
+            .padding()
+
+            Spacer()
+        }
+        .navigationBarTitle(Text(verbatim: landmark.name), displayMode: .inline)
+    }
+}
+
+#if DEBUG
+struct LandmarkDetail_Previews: PreviewProvider {
+    static var previews: some View {
+        LandmarkDetail(landmark: landmarkData[0])
+    }
+}
+#endif

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/LandmarkList.swift

@@ -0,0 +1,33 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+A view showing a list of landmarks.
+*/
+
+import SwiftUI
+
+struct LandmarkList: View {
+    var body: some View {
+        NavigationView {
+            List(landmarkData) { landmark in
+                NavigationButton(destination: LandmarkDetail(landmark: landmark)) {
+                    LandmarkRow(landmark: landmark)
+                }
+            }
+            .navigationBarTitle(Text("Landmarks"), displayMode: .large)
+        }
+    }
+}
+
+#if DEBUG
+struct LandmarkList_Previews: PreviewProvider {
+    static var previews: some View {
+        ForEach(["iPhone SE", "iPhone XS Max"].identified(by: \.self)) { deviceName in
+            LandmarkList()
+                .previewDevice(PreviewDevice(rawValue: deviceName))
+                .previewDisplayName(deviceName)
+        }
+    }
+}
+#endif

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Models/Data.swift

@@ -0,0 +1,93 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+Helpers for loading images and data.
+*/
+
+import UIKit
+import SwiftUI
+import CoreLocation
+
+let landmarkData: [Landmark] = load("landmarkData.json")
+
+func load<T: Decodable>(_ filename: String, as type: T.Type = T.self) -> T {
+    let data: Data
+    
+    guard let file = Bundle.main.url(forResource: filename, withExtension: nil)
+        else {
+            fatalError("Couldn't find \(filename) in main bundle.")
+    }
+    
+    do {
+        data = try Data(contentsOf: file)
+    } catch {
+        fatalError("Couldn't load \(filename) from main bundle:\n\(error)")
+    }
+    
+    do {
+        let decoder = JSONDecoder()
+        return try decoder.decode(T.self, from: data)
+    } catch {
+        fatalError("Couldn't parse \(filename) as \(T.self):\n\(error)")
+    }
+}
+
+final class ImageStore {
+    fileprivate typealias _ImageDictionary = [String: [Int: CGImage]]
+    fileprivate var images: _ImageDictionary = [:]
+    
+    fileprivate static var originalSize = 250
+    fileprivate static var scale = 2
+    
+    static var shared = ImageStore()
+    
+    func image(name: String, size: Int) -> Image {
+        let index = _guaranteeInitialImage(name: name)
+        
+        let sizedImage = images.values[index][size]
+            ?? _sizeImage(images.values[index][ImageStore.originalSize]!, to: size * ImageStore.scale)
+        images.values[index][size] = sizedImage
+        
+        return Image(sizedImage, scale: Length(ImageStore.scale), label: Text(verbatim: name))
+    }
+    
+    fileprivate func _guaranteeInitialImage(name: String) -> _ImageDictionary.Index {
+        if let index = images.index(forKey: name) { return index }
+        
+        guard
+            let url = Bundle.main.url(forResource: name, withExtension: "jpg"),
+            let imageSource = CGImageSourceCreateWithURL(url as NSURL, nil),
+            let image = CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
+            else {
+                fatalError("Couldn't load image \(name).jpg from main bundle.")
+        }
+        
+        images[name] = [ImageStore.originalSize: image]
+        return images.index(forKey: name)!
+    }
+    
+    fileprivate func _sizeImage(_ image: CGImage, to size: Int) -> CGImage {
+        guard
+            let colorSpace = image.colorSpace,
+            let context = CGContext(
+                data: nil,
+                width: size, height: size,
+                bitsPerComponent: image.bitsPerComponent,
+                bytesPerRow: image.bytesPerRow,
+                space: colorSpace,
+                bitmapInfo: image.bitmapInfo.rawValue)
+            else {
+                fatalError("Couldn't create graphics context.")
+        }
+        context.interpolationQuality = .high
+        context.draw(image, in: CGRect(x: 0, y: 0, width: size, height: size))
+        
+        if let sizedImage = context.makeImage() {
+            return sizedImage
+        } else {
+            fatalError("Couldn't resize image.")
+        }
+    }
+}
+

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Models/Landmark.swift

@@ -0,0 +1,40 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+The model for an individual landmark.
+*/
+
+import SwiftUI
+import CoreLocation
+
+struct Landmark: Hashable, Codable, Identifiable {
+    var id: Int
+    var name: String
+    fileprivate var imageName: String
+    fileprivate var coordinates: Coordinates
+    var state: String
+    var park: String
+    var category: Category
+
+    var locationCoordinate: CLLocationCoordinate2D {
+        CLLocationCoordinate2D(
+            latitude: coordinates.latitude,
+            longitude: coordinates.longitude)
+    }
+
+    func image(forSize size: Int) -> Image {
+        ImageStore.shared.image(name: imageName, size: size)
+    }
+
+    enum Category: String, CaseIterable, Codable, Hashable {
+        case featured = "Featured"
+        case lakes = "Lakes"
+        case rivers = "Rivers"
+    }
+}
+
+struct Coordinates: Hashable, Codable {
+    var latitude: Double
+    var longitude: Double
+}

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Preview Content/Preview Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Resources/landmarkData.json

@@ -0,0 +1,158 @@
+[
+    {
+        "name": "Turtle Rock",
+        "category": "Featured",
+        "city": "Twentynine Palms",
+        "state": "California",
+        "id": 1001,
+        "park": "Joshua Tree National Park",
+        "coordinates": {
+            "longitude": -116.166868,
+            "latitude": 34.011286
+        },
+        "imageName": "turtlerock"
+    },
+    {
+        "name": "Silver Salmon Creek",
+        "category": "Lakes",
+        "city": "Port Alsworth",
+        "state": "Alaska",
+        "id": 4,
+        "park": "Lake Clark National Park and Preserve",
+        "coordinates": {
+            "longitude": -152.665167,
+            "latitude": 59.980167
+        },
+        "imageName": "silversalmoncreek"
+    },
+    {
+        "name": "Chilkoot Trail",
+        "category": "Rivers",
+        "city": "Skagway",
+        "state": "Alaska",
+        "id": 5,
+        "park": "Klondike Gold Rush National Historical Park",
+        "coordinates": {
+            "longitude": -135.334571,
+            "latitude": 59.560551
+        },
+        "imageName": "chilkoottrail"
+    },
+    {
+        "name": "St. Mary Lake",
+        "category": "Lakes",
+        "city": "Browning",
+        "state": "Montana",
+        "id": 8,
+        "park": "Glacier National Park",
+        "coordinates": {
+            "longitude": -113.536248,
+            "latitude": 48.69423
+        },
+        "imageName": "stmarylake"
+    },
+    {
+        "name": "Twin Lake",
+        "category": "Lakes",
+        "city": "Twin Lakes",
+        "state": "Alaska",
+        "id": 11,
+        "park": "Lake Clark National Park and Preserve",
+        "coordinates": {
+            "longitude": -153.849883,
+            "latitude": 60.641684
+        },
+        "imageName": "twinlake"
+    },
+    {
+        "name": "Lake McDonald",
+        "category": "Lakes",
+        "city": "West Glacier",
+        "state": "Montana",
+        "id": 6,
+        "park": "Glacier National Park",
+        "coordinates": {
+            "longitude": -113.934831,
+            "latitude": 48.56002
+        },
+        "imageName": "lakemcdonald"
+    },
+    {
+        "name": "Charley Rivers",
+        "category": "Rivers",
+        "city": "Eaking",
+        "state": "Alaska",
+        "id": 1,
+        "park": "Charley Rivers National Preserve",
+        "coordinates": {
+            "longitude": -143.122586,
+            "latitude": 65.350021
+        },
+        "imageName": "yukon_charleyrivers"
+    },
+    {
+        "name": "Icy Bay",
+        "category": "Lakes",
+        "city": "Icy Bay",
+        "state": "Alaska",
+        "id": 2,
+        "park": "Wrangell-St. Elias National Park and Preserve",
+        "coordinates": {
+            "longitude": -141.518167,
+            "latitude": 60.089917
+        },
+        "imageName": "icybay"
+    },
+    {
+        "name": "Rainbow Lake",
+        "category": "Lakes",
+        "city": "Willow",
+        "state": "Alaska",
+        "id": 3,
+        "park": "State Recreation Area",
+        "coordinates": {
+            "longitude": -150.086103,
+            "latitude": 61.694334
+        },
+        "imageName": "rainbowlake"
+    },
+    {
+        "name": "Hidden Lake",
+        "category": "Lakes",
+        "city": "Newhalem",
+        "state": "Washington",
+        "id": 7,
+        "park": "North Cascades National Park",
+        "coordinates": {
+            "longitude": -121.17799,
+            "latitude": 48.495442
+        },
+        "imageName": "hiddenlake"
+    },
+    {
+        "name": "Chincoteague",
+        "category": "Rivers",
+        "city": "Chincoteague",
+        "state": "Virginia",
+        "id": 9,
+        "park": "Chincoteague National Wildlife Refuge",
+        "coordinates": {
+            "longitude": -75.383212,
+            "latitude": 37.91531
+        },
+        "imageName": "chincoteague"
+    },
+    {
+        "name": "Lake Umbagog",
+        "category": "Lakes",
+        "city": "Errol",
+        "state": "New Hampshire",
+        "id": 10,
+        "park": "Umbagog National Wildlife Refuge",
+        "coordinates": {
+            "longitude": -71.056816,
+            "latitude": 44.747408
+        },
+        "imageName": "umbagog"
+    }
+]

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/SceneDelegate.swift

@@ -0,0 +1,56 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+The scene delegate.
+*/
+
+import UIKit
+import SwiftUI
+
+class SceneDelegate: UIResponder, UIWindowSceneDelegate {
+
+    var window: UIWindow?
+
+    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
+        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
+        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
+        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
+
+        // Use a UIHostingController as window root view controller
+        let window = UIWindow(frame: UIScreen.main.bounds)
+        window.rootViewController = UIHostingController(rootView: LandmarkList())
+        self.window = window
+        window.makeKeyAndVisible()
+    }
+
+    func sceneDidDisconnect(_ scene: UIScene) {
+        // Called as the scene is being released by the system.
+        // This occurs shortly after the scene enters the background, or when its session is discarded.
+        // Release any resources associated with this scene that can be re-created the next time the scene connects.
+        // The scene may re-connect later, as its session was not neccessarily discarded (see `application:didDiscardSceneSessions` instead).
+    }
+
+    func sceneDidBecomeActive(_ scene: UIScene) {
+        // Called when the scene has moved from an inactive state to an active state.
+        // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.
+    }
+
+    func sceneWillResignActive(_ scene: UIScene) {
+        // Called when the scene will move from an active state to an inactive state.
+        // This may occur due to temporary interruptions (ex. an incoming phone call).
+    }
+
+    func sceneWillEnterForeground(_ scene: UIScene) {
+        // Called as the scene transitions from the background to the foreground.
+        // Use this method to undo the changes made on entering the background.
+    }
+
+    func sceneDidEnterBackground(_ scene: UIScene) {
+        // Called as the scene transitions from the foreground to the background.
+        // Use this method to save data, release shared resources, and store enough scene-specific state information
+        // to restore the scene back to its current state.
+    }
+
+}
+

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Supporting Views/CircleImage.swift

@@ -0,0 +1,27 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+A view that clips an image to a circle and adds a stroke and shadow.
+*/
+
+import SwiftUI
+
+struct CircleImage: View {
+    var image: Image
+
+    var body: some View {
+        image
+            .clipShape(Circle())
+            .overlay(Circle().stroke(Color.white, lineWidth: 4))
+            .shadow(radius: 10)
+    }
+}
+
+#if DEBUG
+struct CircleImage_Previews: PreviewProvider {
+    static var previews: some View {
+        CircleImage(image: Image("turtlerock"))
+    }
+}
+#endif

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Supporting Views/LandmarkRow.swift

@@ -0,0 +1,32 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+A single row to be displayed in a list of landmarks.
+*/
+
+import SwiftUI
+
+struct LandmarkRow: View {
+    var landmark: Landmark
+
+    var body: some View {
+        HStack {
+            landmark.image(forSize: 50)
+            Text(verbatim: landmark.name)
+            Spacer()
+        }
+    }
+}
+
+#if DEBUG
+struct LandmarkRow_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            LandmarkRow(landmark: landmarkData[0])
+            LandmarkRow(landmark: landmarkData[1])
+        }
+        .previewLayout(.fixed(width: 300, height: 70))
+    }
+}
+#endif

Examples/Building Lists And Navigation/Complete/Landmarks/Landmarks/Supporting Views/MapView.swift

@@ -0,0 +1,31 @@
+/*
+See LICENSE folder for this sample’s licensing information.
+
+Abstract:
+A view that hosts an `MKMapView`.
+*/
+
+import SwiftUI
+import MapKit
+
+struct MapView: UIViewRepresentable {
+    var coordinate: CLLocationCoordinate2D
+
+    func makeUIView(context: Context) -> MKMapView {
+        MKMapView(frame: .zero)
+    }
+
+    func updateUIView(_ view: MKMapView, context: Context) {
+        let span = MKCoordinateSpan(latitudeDelta: 0.02, longitudeDelta: 0.02)
+        let region = MKCoordinateRegion(center: coordinate, span: span)
+        view.setRegion(region, animated: true)
+    }
+}
+
+#if DEBUG
+struct MapView_Previews: PreviewProvider {
+    static var previews: some View {
+        MapView(coordinate: landmarkData[0].locationCoordinate)
+    }
+}
+#endif