Generate offline map

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 // Copyright 2022 Esri // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License.  import ArcGIS import SwiftUI  struct GenerateOfflineMapView: View {  /// A Boolean value indicating whether the job is generating an offline map.  @State private var isGeneratingOfflineMap = false   /// A Boolean value indicating whether the job is cancelling.  @State private var isCancellingJob = false   /// The error shown in the error alert.  @State private var error: Error?   /// The view model for this sample.  @StateObject private var model = Model()   var body: some View {  GeometryReader { geometry in  MapViewReader { mapView in  MapView(map: model.offlineMap ?? model.onlineMap)  .interactionModes(isGeneratingOfflineMap ? [] : [.pan, .zoom])  .errorAlert(presentingError: $error)  .task {  do {  try await model.initializeOfflineMapTask()  } catch {  self.error = error  }  }  .onDisappear {  Task { await model.cancelJob() }  }  .overlay {  Rectangle()  .stroke(.red, lineWidth: 2)  .padding(EdgeInsets(top: 20, leading: 20, bottom: 44, trailing: 20))  .opacity(model.offlineMap == nil ? 1 : 0)  }  .overlay {  if isGeneratingOfflineMap,  let progress = model.generateOfflineMapJob?.progress {  VStack(spacing: 16) {  ProgressView(progress)  .progressViewStyle(.linear)  .frame(maxWidth: 200)   Button("Cancel") {  isCancellingJob = true  }  .disabled(isCancellingJob)  .task(id: isCancellingJob) {  // Ensures cancelling the job is true.  guard isCancellingJob else { return }  // Cancels the job.  await model.cancelJob()  // Sets cancelling the job and generating an  // offline map to false.  isCancellingJob = false  isGeneratingOfflineMap = false  }  }  .padding()  .background(.regularMaterial)  .clipShape(RoundedRectangle(cornerRadius: 15))  .shadow(radius: 3)  }  }  .overlay(alignment: .top) {  if model.offlineMap != nil {  Text("Offline map generated.")  .frame(maxWidth: .infinity, alignment: .center)  .padding(8)  .background(.thinMaterial, ignoresSafeAreaEdges: .horizontal)  }  }  .toolbar {  ToolbarItem(placement: .bottomBar) {  Button("Generate Offline Map") {  isGeneratingOfflineMap = true  }  .disabled(model.isGenerateDisabled || isGeneratingOfflineMap)  .task(id: isGeneratingOfflineMap) {  // Ensures generating an offline map is true.  guard isGeneratingOfflineMap else { return }   // Creates a rectangle from the area of interest.  let viewRect = geometry.frame(in: .local).inset(  by: UIEdgeInsets(  top: 20,  left: geometry.safeAreaInsets.leading + 20,  bottom: 44,  right: -geometry.safeAreaInsets.trailing + 20  )  )   // Creates an envelope from the rectangle.  guard let extent = mapView.envelope(fromViewRect: viewRect) else { return }   do {  // Generates an offline map.  try await model.generateOfflineMap(extent: extent)  } catch {  self.error = error  }   // Sets generating an offline map to false.  isGeneratingOfflineMap = false  }  }  }  }  }  } }  private extension GenerateOfflineMapView {  /// The model used to store the geo model and other expensive objects  /// used in this view.  @MainActor  class Model: ObservableObject {  /// The offline map that is generated.  @Published private(set) var offlineMap: Map!   /// A Boolean value indicating whether the generate button is disabled.  @Published private(set) var isGenerateDisabled = true   /// The generate offline map job.  @Published private(set) var generateOfflineMapJob: GenerateOfflineMapJob!   /// The offline map task.  private var offlineMapTask: OfflineMapTask!   /// A URL to a temporary directory where the offline map files are stored.  private let temporaryDirectory = createTemporaryDirectory()   /// A portal item displaying the Naperville, IL water network.  private let napervillePortalItem = PortalItem(  portal: .arcGISOnline(connection: .anonymous),  id: PortalItem.ID("acc027394bc84c2fb04d1ed317aac674")!  )   /// The online map that is loaded from a portal item.  let onlineMap: Map   init() {  // Initializes the online map.  onlineMap = Map(item: napervillePortalItem)  // Sets the min scale to avoid requesting a huge download.  onlineMap.minScale = 1e4  }   deinit {  // Removes the temporary directory.  try? FileManager.default.removeItem(at: temporaryDirectory)  }   /// Initializes the offline map task.  func initializeOfflineMapTask() async throws {  // Waits for the online map to load.  try await onlineMap.load()  offlineMapTask = OfflineMapTask(onlineMap: onlineMap)  isGenerateDisabled = false  }   /// Creates the generate offline map parameters.  /// - Parameter areaOfInterest: The area of interest to create the parameters for.  /// - Returns: A `GenerateOfflineMapParameters` if there are no errors.  private func makeGenerateOfflineMapParameters(areaOfInterest: Envelope) async throws -> GenerateOfflineMapParameters {  // Returns the default parameters for the offline map task.  return try await offlineMapTask.makeDefaultGenerateOfflineMapParameters(areaOfInterest: areaOfInterest)  }   /// Generates the offline map.  /// - Parameter extent: The area of interest's envelope to generate an offline map for.  func generateOfflineMap(extent: Envelope) async throws {  // Disables the generate offline map button.  isGenerateDisabled = true   // Creates the default parameters for the offline map task.  let parameters = try await makeGenerateOfflineMapParameters(areaOfInterest: extent)   // Creates the generate offline map job based on the parameters.  generateOfflineMapJob = offlineMapTask.makeGenerateOfflineMapJob(  parameters: parameters,  downloadDirectory: temporaryDirectory  )   // Starts the job.  generateOfflineMapJob.start()   defer {  generateOfflineMapJob = nil  isGenerateDisabled = offlineMap != nil  }   // Awaits the output of the job.  let output = try await generateOfflineMapJob.output  // Sets the offline map to the output's offline map.  offlineMap = output.offlineMap  // Sets the initial viewpoint of the offline map.  offlineMap.initialViewpoint = Viewpoint(boundingGeometry: extent.expanded(by: 0.8))  }   /// Cancels the generate offline map job.  func cancelJob() async {  // Cancels the generate offline map job.  await generateOfflineMapJob?.cancel()  generateOfflineMapJob = nil  }   /// Creates a temporary directory.  private static func createTemporaryDirectory() -> URL {  // swiftlint:disable:next force_try  try! FileManager.default.url(  for: .itemReplacementDirectory,  in: .userDomainMask,  appropriateFor: FileManager.default.temporaryDirectory,  create: true  )  }  } }  private extension Envelope {  /// Expands the envelope by a given factor.  func expanded(by factor: Double) -> Envelope {  let builder = EnvelopeBuilder(envelope: self)  builder.expand(by: factor)  return builder.toGeometry()  } }  #Preview {  NavigationStack {  GenerateOfflineMapView()  } }