&tag(SwiftUI/BuildingListsAndNavigation);
struct Landmark: Hashable, Codable {
var id: Int
var name: String
var park: String
var state: String
var description: String
}
struct Landmark: Hashable, Codable {
var id: Int
var name: String
var park: String
var state: String
var description: String
private var imageName: String
var image: Image {
Image(imageName)
}
}
struct Landmark: Hashable, Codable {
var id: Int
var name: String
var park: String
var state: String
var description: String
private var imageName: String
var image: Image {
Image(imageName)
}
private var coordinates: Coordinates
var locationCoordinate: CLLocationCoordinate2D {
CLLocationCoordinate2D(
latitude: coordinates.latitude,
longitude: coordinates.longitude)
}
struct Coordinates: Hashable, Codable {
var latitude: Double
var longitude: Double
}
}
var landmarks: [Landmark] = load("landmarkData.json")
func load<T: Decodable>(_ filename: String) -> 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)")
}
struct LandmarkRow: View {
var landmark: Landmark
var body: some View {
HStack {
landmark.image
.resizable()
.frame(width: 50, height: 50)
Text(landmark.name)
Spacer()
}
}
}
struct LandmarkRow_Previews: PreviewProvider {
static var previews: some View {
LandmarkRow(landmark: landmarks[0]);
}
}
struct LandmarkRow_Previews: PreviewProvider {
static var previews: some View {
LandmarkRow(landmark: landmarks[1]).previewLayout(.fixed(width: 300, height: 70))
}
}
Group {
LandmarkRow(landmark: landmarks[0])
.previewLayout(.fixed(width: 300, height: 70))
LandmarkRow(landmark: landmarks[1])
.previewLayout(.fixed(width: 300, height: 70))
}
リストビューを実装する。
struct LandmarkList: View {
var body: some View {
List {
LandmarkRow(landmark: landmarks[0])
LandmarkRow(landmark: landmarks[1])
}
}
}
Listにコレクションを表示。
struct LandmarkList: View {
var body: some View {
List(landmarks, id: \.id) { landmark in
LandmarkRow(landmark: landmark)
}
}
リストと詳細をナビゲートできるようにする。
struct LandmarkDetail: View {
var body: some View {
VStack {
MapView()
.ignoresSafeArea(edges: .top)
.frame(height: 300)
CircleImage()
.offset(y: -130)
.padding(.bottom, -130)
VStack(alignment: .leading) {
Text("Turtle Rock")
.font(.title)
.foregroundColor(.primary)
HStack {
Text("Joshua Tree National Park")
Spacer()
Text("California")
}
.font(.subheadline)
.foregroundColor(.secondary)
Divider()
Text("About Turtle Rock")
.font(.title2)
Text("Descriptive text goes here.")
}
.padding()
Spacer()
}
}
}
struct ContentView: View {
var body: some View {
LandmarkList()
}
}
struct LandmarkList: View {
var body: some View {
NavigationView {
List(landmarks) { landmark in
NavigationLink(destination: LandmarkDetail()) {
LandmarkRow(landmark: landmark)
}
}
.navigationTitle("Landmarks")
}
}
}
-ライブプレビューで遷移を確認可能。
詳細ビューにデータを引き渡す。
struct CircleImage: View {
var image: Image
var body: some View {
image
.clipShape(Circle())
.overlay(Circle().stroke(Color.white, lineWidth: 4))
.shadow(radius: 7)
}
}
struct CircleImage_Previews: PreviewProvider {
static var previews: some View {
CircleImage(image: Image("turtlerock"))
}
}
struct MapView: View {
var coordinate: CLLocationCoordinate2D
@State private var region = MKCoordinateRegion()
var body: some View {
Map(coordinateRegion: $region)
.onAppear {
setRegion(coordinate)
}
}
private func setRegion(_ coordinate: CLLocationCoordinate2D) {
region = MKCoordinateRegion(
center: coordinate,
span: MKCoordinateSpan(latitudeDelta: 0.2, longitudeDelta: 0.2)
)
}
}
struct MapView_Previews: PreviewProvider {
static var previews: some View {
MapView(coordinate: CLLocationCoordinate2D(latitude: 34.011_286, longitude: -116.166_868))
}
}
struct LandmarkDetail: View {
var landmark: Landmark
var body: some View {
ScrollView {
MapView(coordinate: landmark.locationCoordinate)
.ignoresSafeArea(edges: .top)
.frame(height: 300)
CircleImage(image: landmark.image)
.offset(y: -130)
.padding(.bottom, -130)
VStack(alignment: .leading) {
Text(landmark.name)
.font(.title)
.foregroundColor(.primary)
HStack {
Text(landmark.park)
Spacer()
Text(landmark.state)
}
.font(.subheadline)
.foregroundColor(.secondary)
Divider()
Text("About \(landmark.name)")
.font(.title2)
Text(landmark.description)
}
.padding()
}
.navigationTitle(landmark.name)
.navigationBarTitleDisplayMode(.inline)
}
}
struct LandmarkDetail_Previews: PreviewProvider {
static var previews: some View {
Group {
LandmarkDetail(landmark: landmarks[0])
}
}
}
プレビューを修正する。
struct LandmarkList: View {
var body: some View {
NavigationView {
List(landmarks) { landmark in
NavigationLink(destination: LandmarkDetail(landmark: landmark)) {
LandmarkRow(landmark: landmark)
}
}
.navigationTitle("Landmarks")
}
}
}
struct LandmarkList_Previews: PreviewProvider {
static var previews: some View {
ForEach(["iPhone SE (2nd generation)", "iPhone XS Max"], id: \.self) { deviceName in
LandmarkList()
.previewDevice(PreviewDevice(rawValue: deviceName))
.previewDisplayName(deviceName)
}
}
}