创建和显示多目的地行程

多目的地行程是指消费者与司机一起安排的专属行程,该司机可能在到达消费者最初请求的目的地之前经停一或多处。

多目的地行程和单目的地行程的主要区别在于,对于多目的地行程,行程运营商可以在出发地和下车点之间设置一个或多个经停点。

本教程将引导您完成创建多目的地行程的流程。此外,它还展示了如何随后将该行程与您的消费者应用集成,以便您的客户可以通过他们的手机查看行程进度。您可以使用 ConsumerSDK 来进行此集成。

前提条件

如需完成本教程,请务必完成以下操作:

  1. 设置 Fleet Engine。如需了解详情,请参阅 Fleet Engine:初始设置

  2. 将您的应用与驱动程序 SDK 集成。如需了解详情,请参阅 初始化驱动程序 SDK驱动程序 SDK 集成指南

  3. 将面向消费者的应用与消费者 SDK 集成。如需了解详情,请参阅 开始使用消费者 SDK消费者 SDK 使用入门

  4. 设置授权令牌。有关授权令牌的更多信息,请参阅 Fleet Engine 使用入门指南中的创建用于授权的 JSON Web 令牌;以及 Fleet Engine 的使用方 SDK 文档中的身份验证和授权

第 1 步:在 Fleet Engine 中创建车辆

车辆是代表车队中车辆的对象。您必须创建 Fleet Engine 中的实例,以便能够在消费者应用中跟踪它们。

您可以使用以下两种方法之一制作车辆:

gRPC
致电CreateVehicle() 方法(其中包含 CreateVehicleRequest 请求消息。您必须拥有 Fleet Engine 超级用户权限才能调用 CreateVehicle()
REST
拨打 https://fleetengine.googleapis.com/v1/providers.vehicles.create

注意事项

制作车辆时,请注意以下事项。

  • 请务必将车辆的初始状态设为 OFFLINE。这样可确保 Fleet Engine 能够发现您的车辆,以便匹配行程。

  • 车辆的 provider_id 必须与 包含用于调用舰队的服务账号的 Google Cloud 项目 。虽然多个服务账号可以在同一个项目中访问 Fleet Engine, 拼车服务提供商,Fleet Engine 目前不支持 访问相同车辆的不同 Google Cloud 项目。

  • CreateVehicle() 返回的响应包含 Vehicle 实例。 如果 7 天后该实例仍未使用 UpdateVehicle()。您应该先调用 GetVehicle(),然后再调用 CreateVehicle() 只是为了确认车辆尚不存在。如果 GetVehicle() 返回 NOT_FOUND 错误,则您应继续调用 CreateVehicle()。如需了解详情,请参阅 交通工具及其生命周期

示例

以下提供程序代码示例演示了如何在 Fleet Engine

static final String PROJECT_ID = "my-rideshare-co-gcp-project";

VehicleServiceBlockingStub vehicleService = VehicleService.newBlockingStub(channel);

String parent = "providers/" + PROJECT_ID;

Vehicle vehicle = Vehicle.newBuilder()
    .setVehicleState(VehicleState.OFFLINE)  // Initial state
    .addSupportedTripTypes(TripType.EXCLUSIVE)
    .setMaximumCapacity(4)
    .setVehicleType(VehicleType.newBuilder().setCategory(VehicleType.Category.AUTO))
    .build();

CreateVehicleRequest createVehicleRequest = CreateVehicleRequest.newBuilder()
    .setParent(parent)
    .setVehicleId("8241890")  // Vehicle ID assigned by solution provider.
    .setVehicle(vehicle)      // Initial state.
    .build();

// The Vehicle is created in the OFFLINE state, and no initial position is
// provided.  When the driver app calls the rideshare provider, the state can be
// set to ONLINE, and the driver app updates the vehicle location.
try {
  Vehicle createdVehicle = vehicleService.createVehicle(createVehicleRequest);
} catch (StatusRuntimeException e) {
  Status s = e.getStatus();
  switch (s.getCode()) {
    case ALREADY_EXISTS:
      break;
    case PERMISSION_DENIED:
      break;
  }
  return;
}

第 2 步:启用位置跟踪

位置跟踪是指跟踪车辆在行程中的位置。 其中,Driver 应用将遥测数据发送到 Fleet Engine,其中包含 车辆当前位置。这个不断更新的位置流 信息用于传递车辆在行程路线中的进度。 启用位置跟踪功能后,驾驶员应用就会开始发送此遥测数据, 以每 5 秒一次的默认频率运行。

您可以按如下方式为 Android 和 iOS 启用位置跟踪:

示例

以下代码示例演示了如何启用位置跟踪。

Java

RidesharingVehicleReporter vehicleReporter = ...;

vehicleReporter.enableLocationTracking();

Kotlin

val vehicleReporter = ...

vehicleReporter.enableLocationTracking()

Swift

vehicleReporter.locationTrackingEnabled = true

Objective-C

_vehicleReporter.locationTrackingEnabled = YES;

第 3 步:将车辆的状态设为在线

您需要通过以下方式安排车辆进入维修(即,使其可供使用) 并将其状态设置为 online,但必须先完成操作,然后才能 已启用位置跟踪。

对于 Android 和 iOS,您需要将车辆的状态设置为在线,具体操作步骤如下:

示例

以下代码示例演示了如何将车辆的状态设置为 ONLINE

Java

vehicleReporter.setVehicleState(VehicleState.ONLINE);

Kotlin

vehicleReporter.setVehicleState(VehicleState.ONLINE)

Swift

vehicleReporter.update(.online)

Objective-C

[_vehicleReporter updateVehicleState:GMTDVehicleStateOnline];

第 4 步:在 Fleet Engine 中创建行程

如需创建多目的地行程,您必须像创建单目的地一样创建 Trip 对象。

行程是表示行程的对象,是一个地理坐标点集合,包括起点、航点和下车点。 您必须为每个行程请求创建一个 Trip 对象,以便将该请求与车辆匹配并进行跟踪。

提供必需属性

以下字段是创建多目的地行程的必填字段。

parent
包含提供方 ID 的字符串。该名称必须与 包含服务账号的 Google Cloud 项目的 ID 用于调用 Fleet Engine
trip_id
您创建的一个字符串,用于唯一标识此行程。
trip
要创建的“Trip”对象。

您必须在传递给 CreateTripRequestTrip 对象中设置以下字段:

trip_type
TripType.EXCLUSIVE
pickup_point
行程的出发地。
dropoff_point
行程的下车点。此字段在行程创建期间不是必填字段,可以稍后通过调用“UpdateTrip”进行设置。
intermediate_destinations
司机在上车点和下车点之间访问的中间目的地列表。与下车点一样,创建行程时不需要填写此字段,您可以通过调用“UpdateTrip”进行设置。

示例

以下后端集成示例演示了如何创建 一个多目的地行程,设有上车点、下车点和 目标。

static final String PROJECT_ID = "my-rideshare-co-gcp-project";
static final String TRIP_ID = "multi-destination-trip-A";

TripServiceBlockingStub tripService = TripService.newBlockingStub(channel);

// Trip initial settings.
String parent = "providers/" + PROJECT_ID;

Trip trip = Trip.newBuilder()
    .setTripType(TripType.EXCLUSIVE)
    .setPickupPoint(
        TerminalLocation.newBuilder().setPoint(
            LatLng.newBuilder()
                .setLatitude(-6.195139).setLongitude(106.820826)))
    .setNumberOfPassengers(1)
    .setDropoffPoint(
        TerminalLocation.newBuilder().setPoint(
            LatLng.newBuilder()
                .setLatitude(-6.1275).setLongitude(106.6537)))
    // Add the list of intermediate destinations.
    .addAllIntermediateDestinations(
        ImmutableList.of(
            TerminalLocation.newBuilder().setPoint(
                LatLng.newBuilder()
                    .setLatitude(-6.195139).setLongitude(106.820826)).build()))
    .build();

// Create the Trip request.
CreateTripRequest createTripRequest = CreateTripRequest.newBuilder()
    .setParent(parent)
    .setTripId(TRIP_ID)  // Trip ID assigned by the Provider server.
    .setTrip(trip)       // Initial state is NEW.
    .build();

// Error handling.
try {
  Trip createdTrip =
      tripService.createTrip(createTripRequest);
} catch (StatusRuntimeException e) {
  Status s = e.getStatus();
  switch (s.getCode()) {
    case ALREADY_EXISTS:  // Trip already exists.
      break;
    case PERMISSION_DENIED:
      break;
  }
  return;
}

第 5 步:使用车辆 ID 和航点更新行程

您必须使用车辆 ID 配置行程,以便 Fleet Engine 可以跟踪 沿途车辆

备注

  • 如果您在创建行程时未指定下车点或中间目的地,此时随时可以指定。

  • 如果您需要更换正在进行的行程中的车辆,则必须设置 将行程的状态重新更新为新的行程状态,然后使用 新车 ID。

示例

以下后端集成示例演示了如何更新行程以添加 中间目的地列表并设置车辆 ID。

static final String PROJECT_ID = "my-rideshare-co-gcp-project";
static final String TRIP_ID = "multi-destination-trip-A";

String tripName = "providers/" + PROJECT_ID + "/trips/" + TRIP_ID;

TripServiceBlockingStub tripService = TripService.newBlockingStub(channel);

// The trip settings to be updated.
Trip trip = Trip.newBuilder()
    // Add the list of intermediate destinations.
    .addAllIntermediateDestinations(
        ImmutableList.of(
            TerminalLocation.newBuilder().setPoint(
                LatLng.newBuilder()
                    .setLatitude(-6.195139).setLongitude(106.820826)).build()))
    .setVehicleId("8241890")
    .build();

// The trip update request.
UpdateTripRequest updateTripRequest = UpdateTripRequest.newBuilder()
    .setName(tripName)
    .setTrip(trip)
    .setUpdateMask(
        FieldMask.newBuilder()
            .addPaths("intermediate_destinations")
            .addPaths("vehicle_id")
            .build())
    .build();

// Error handling.
try {
  Trip updatedTrip =
      tripService.updateTrip(updateTripRequest);
} catch (StatusRuntimeException e) {
  Status s = e.getStatus();
  switch (s.getCode()) {
    case NOT_FOUND:            // The trip doesn't exist.
      break;
    case PERMISSION_DENIED:
      break;
  }
  return;
}

第 6 步:在消费者应用中监听行程更新

  • 对于 Android,您可以通过获取 TripModel 对象来监听行程中的数据更新 并注册 TripModelCallback 监听器。TripModelManager

  • 对于 iOS,您可以通过获取 GMTCTripModel 对象来监听行程中的数据更新 并注册 GMTCTripModelSubscriber 订阅者。GMTCTripService

TripModelCallback 监听器和 GMTCTripModelSubscriber 订阅者可让您的应用定期接收 根据自动刷新间隔,在每次刷新时更新行程进度。 只有发生更改的值才能触发回调。否则, 不会发出任何通知

无论数据发生任何更改,系统始终会调用 TripModelCallback.onTripUpdated()tripModel(_:didUpdate:updatedPropertyFields:) 方法。

示例 1

以下代码示例演示了如何从 Google Cloud 获取 TripModel TripModelManager/GMTCTripService,并为其设置监听器。

Java

// Start journey sharing after a trip has been created via Fleet Engine.
TripModelManager tripModelManager = consumerApi.getTripModelManager();

// Get a TripModel object.
TripModel tripModel = tripModelManager.getTripModel(tripName);

// Register a listener on the trip.
TripModelCallback tripCallback = new TripModelCallback() {
  ...
};
tripModel.registerTripCallback(tripCallback);

// Set the refresh interval.
TripModelOptions tripModelOptions = TripModelOptions.builder()
    .setRefreshInterval(5000) // interval in milliseconds, so 5 seconds
    .build();
tripModel.setTripModelOptions(tripModelOptions);

// The trip stops auto-refreshing when all listeners are unregistered.
tripModel.unregisterTripCallback(tripCallback);

Kotlin

// Start journey sharing after a trip has been created via Fleet Engine.
val tripModelManager = consumerApi.getTripModelManager()

// Get a TripModel object.
val tripModel = tripModelManager.getTripModel(tripName)

// Register a listener on the trip.
val tripCallback = TripModelCallback() {
  ...
}

tripModel.registerTripCallback(tripCallback)

// Set the refresh interval.
val tripModelOptions =
  TripModelOptions.builder()
    .setRefreshInterval(5000) // interval in milliseconds, so 5 seconds
    .build()

tripModel.setTripModelOptions(tripModelOptions)

// The trip stops auto-refreshing when all listeners are unregistered.
tripModel.unregisterTripCallback(tripCallback)

Swift

let tripService = GMTCServices.shared().tripService

// Create a tripModel instance for listening for updates from the trip
// specified by the trip name.
let tripModel = tripService.tripModel(forTripName: tripName)

// Register for the trip update events.
tripModel.register(self)

// Set the refresh interval (in seconds).
tripModel.options.autoRefreshTimeInterval = 5

// Unregister for the trip update events.
tripModel.unregisterSubscriber(self)

Objective-C

GMTCTripService *tripService = [GMTCServices sharedServices].tripService;

// Create a tripModel instance for listening for updates from the trip
// specified by the trip name.
GMTCTripModel *tripModel = [tripService tripModelForTripName:tripName];

// Register for the trip update events.
[tripModel registerSubscriber:self];

// Set the refresh interval (in seconds).
tripModel.options.autoRefreshTimeInterval = 5;

// Unregister for the trip update events.
[tripModel unregisterSubscriber:self];

示例 2

以下代码示例演示了如何设置 TripModelCallback 监听器和 GMTCTripModelSubscriber 个订阅者。

Java

// Implements a callback for the trip model so your app can listen for trip
// updates from Fleet Engine.
TripModelCallback subscriber =
  new TripModelCallback() {

    @Override
    public void onTripStatusUpdated(TripInfo tripInfo, @TripStatus int status) {
      // ...
    }

    @Override
    public void onTripActiveRouteUpdated(TripInfo tripInfo, List<LatLng> route) {
      // ...
    }

    @Override
    public void onTripVehicleLocationUpdated(
        TripInfo tripInfo, @Nullable VehicleLocation vehicleLocation) {
      // ...
    }

    @Override
    public void onTripPickupLocationUpdated(
        TripInfo tripInfo, @Nullable TerminalLocation pickup) {
      // ...
    }

    @Override
    public void onTripPickupTimeUpdated(TripInfo tripInfo, @Nullable Long timestampMillis) {
      // ...
    }

    @Override
    public void onTripDropoffLocationUpdated(
        TripInfo tripInfo, @Nullable TerminalLocation dropoff) {
      // ...
    }

    @Override
    public void onTripDropoffTimeUpdated(TripInfo tripInfo, @Nullable Long timestampMillis) {
      // ...
    }

    @Override
    public void onTripETAToNextWaypointUpdated(
        TripInfo tripInfo, @Nullable Long timestampMillis) {
      // ...
    }

    @Override
    public void onTripActiveRouteRemainingDistanceUpdated(
        TripInfo tripInfo, @Nullable Integer distanceMeters) {
      // ...
    }

    @Override
    public void onTripUpdateError(TripInfo tripInfo, TripUpdateError error) {
      // ...
    }

    @Override
    public void onTripUpdated(TripInfo tripInfo) {
      // ...
    }

    @Override
    public void onTripRemainingWaypointsUpdated(
        TripInfo tripInfo, List<TripWaypoint> waypointList) {
      // ...
    }

    @Override
    public void onTripIntermediateDestinationsUpdated(
        TripInfo tripInfo, List<TerminalLocation> intermediateDestinations) {
      // ...
    }

    @Override
    public void onTripRemainingRouteDistanceUpdated(
        TripInfo tripInfo, @Nullable Integer distanceMeters) {
      // ...
    }

    @Override
    public void onTripRemainingRouteUpdated(TripInfo tripInfo, List<LatLng> route) {
      // ...
    }
  };

Kotlin

// Implements a callback for the trip model so your app can listen for trip
// updates from Fleet Engine.
val subscriber =
  object : TripModelCallback() {
    override fun onTripStatusUpdated(tripInfo: TripInfo, status: @TripStatus Int) {
      // ...
    }

    override fun onTripActiveRouteUpdated(tripInfo: TripInfo, route: List<LatLng>) {
      // ...
    }

    override fun onTripVehicleLocationUpdated(
      tripInfo: TripInfo,
      vehicleLocation: VehicleLocation?
    ) {
      // ...
    }

    override fun onTripPickupLocationUpdated(tripInfo: TripInfo, pickup: TerminalLocation?) {
      // ...
    }

    override fun onTripPickupTimeUpdated(tripInfo: TripInfo, timestampMillis: Long?) {
      // ...
    }

    override fun onTripDropoffLocationUpdated(tripInfo: TripInfo, dropoff: TerminalLocation?) {
      // ...
    }

    override fun onTripDropoffTimeUpdated(tripInfo: TripInfo, timestampMillis: Long?) {
      // ...
    }

    override fun onTripETAToNextWaypointUpdated(tripInfo: TripInfo, timestampMillis: Long?) {
      // ...
    }

    override fun onTripActiveRouteRemainingDistanceUpdated(
      tripInfo: TripInfo,
      distanceMeters: Int?
    ) {
      // ...
    }

    override fun onTripUpdateError(tripInfo: TripInfo, error: TripUpdateError) {
      // ...
    }

    override fun onTripUpdated(tripInfo: TripInfo) {
      // ...
    }

    override fun onTripRemainingWaypointsUpdated(
      tripInfo: TripInfo,
      waypointList: List<TripWaypoint>
    ) {
      // ...
    }

    override fun onTripIntermediateDestinationsUpdated(
      tripInfo: TripInfo,
      intermediateDestinations: List<TerminalLocation>
    ) {
      // ...
    }

    override fun onTripRemainingRouteDistanceUpdated(tripInfo: TripInfo, distanceMeters: Int?) {
      // ...
    }

    override fun onTripRemainingRouteUpdated(tripInfo: TripInfo, route: List<LatLng>) {
      // ...
    }
  }

Swift

class TripModelSubscriber: NSObject, GMTCTripModelSubscriber {

  func tripModel(_: GMTCTripModel, didUpdate trip: GMTSTrip?, updatedPropertyFields: GMTSTripPropertyFields) {
    // Update the UI with the new `trip` data.
    updateUI(with: trip)
    ...
  }

  func tripModel(_: GMTCTripModel, didUpdate tripStatus: GMTSTripStatus) {
    // Handle trip status did change.
  }

  func tripModel(_: GMTCTripModel, didUpdateActiveRoute activeRoute: [GMTSLatLng]?) {
    // Handle trip active route did update.
  }

  func tripModel(_: GMTCTripModel, didUpdate vehicleLocation: GMTSVehicleLocation?) {
    // Handle vehicle location did update.
  }

  func tripModel(_: GMTCTripModel, didUpdatePickupLocation pickupLocation: GMTSTerminalLocation?) {
    // Handle pickup location did update.
  }

  func tripModel(_: GMTCTripModel, didUpdateDropoffLocation dropoffLocation: GMTSTerminalLocation?) {
    // Handle drop off location did update.
  }

  func tripModel(_: GMTCTripModel, didUpdatePickupETA pickupETA: TimeInterval) {
    // Handle the pickup ETA did update.
  }

  func tripModel(_: GMTCTripModel, didUpdateDropoffETA dropoffETA: TimeInterval) {
    // Handle the drop off ETA did update.
  }

  func tripModel(_: GMTCTripModel, didUpdateRemaining remainingWaypoints: [GMTSTripWaypoint]?) {
    // Handle updates to the pickup, dropoff or intermediate destinations of the trip.
  }

  func tripModel(_: GMTCTripModel, didFailUpdateTripWithError error: Error?) {
    // Handle the error.
  }

  func tripModel(_: GMTCTripModel, didUpdateIntermediateDestinations intermediateDestinations: [GMTSTerminalLocation]?) {
    // Handle the intermediate destinations being updated.
  }

  ...
}

Objective-C

@interface TripModelSubscriber : NSObject <GMTCTripModelSubscriber>
@end

@implementation TripModelSubscriber

- (void)tripModel:(GMTCTripModel *)tripModel
            didUpdateTrip:(nullable GMTSTrip *)trip
    updatedPropertyFields:(GMTSTripPropertyFields)updatedPropertyFields {
  // Update the UI with the new `trip` data.
  [self updateUIWithTrip:trip];
  ...
}

- (void)tripModel:(GMTCTripModel *)tripModel didUpdateTripStatus:(enum GMTSTripStatus)tripStatus {
  // Handle trip status did change.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdateActiveRoute:(nullable NSArray<GMTSLatLng *> *)activeRoute {
  // Handle trip route did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdateVehicleLocation:(nullable GMTSVehicleLocation *)vehicleLocation {
  // Handle vehicle location did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdatePickupLocation:(nullable GMTSTerminalLocation *)pickupLocation {
  // Handle pickup location did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdateDropoffLocation:(nullable GMTSTerminalLocation *)dropoffLocation {
  // Handle drop off location did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel didUpdatePickupETA:(NSTimeInterval)pickupETA {
  // Handle the pickup ETA did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdateRemainingWaypoints:(nullable NSArray<GMTSTripWaypoint *> *)remainingWaypoints {
  // Handle updates to the pickup, dropoff or intermediate destinations of the trip.
}

- (void)tripModel:(GMTCTripModel *)tripModel didUpdateDropoffETA:(NSTimeInterval)dropoffETA {
  // Handle the drop off ETA did update.
}

- (void)tripModel:(GMTCTripModel *)tripModel didFailUpdateTripWithError:(nullable NSError *)error {
  // Handle the error.
}

- (void)tripModel:(GMTCTripModel *)tripModel
    didUpdateIntermediateDestinations:
        (nullable NSArray<GMTSTerminalLocation *> *)intermediateDestinations {
  // Handle the intermediate destinations being updated.
}
…
@end

您可以按以下步骤随时访问该行程的信息:

第 7 步:在消费者应用中显示历程

您可以按如下方式访问 Rides and Deliveries 界面元素 API:

示例

以下代码示例演示了如何开始分享用户历程 界面。

Java

JourneySharingSession session = JourneySharingSession.createInstance(tripModel);
consumerController.showSession(session);

Kotlin

val session = JourneySharingSession.createInstance(tripModel)
consumerController.showSession(session)

Swift

let journeySharingSession = GMTCJourneySharingSession(tripModel: tripModel)
mapView.show(journeySharingSession)

Objective-C

GMTCJourneySharingSession *journeySharingSession =
    [[GMTCJourneySharingSession alloc] initWithTripModel:tripModel];
[self.mapView showMapViewSession:journeySharingSession];

默认情况下,使用方 SDK 仅显示路线中的活动路程, 可以选择显示剩余路程,其中包括中间目的地和下车点。

如果您想显示有关其他行程中的航点的信息, 可以访问与行程相关的所有航点,如下所示:

第 8 步:在 Fleet Engine 中管理行程状态

您可以使用 TripStatus 枚举值。当行程的状态发生变化时(例如,从 ENROUTE_TO_PICKUPARRIVED_AT_PICKUP),您必须通过以下方式更新行程状态: Fleet Engine行程状态始终以值 NEW 开始,以 值为 COMPLETECANCELED。如需了解详情,请参阅 trip_status

对于多目的地行程,除了在更新过程中 ,那么您还必须更新 intermediateDestinationIndex,并提供 intermediateDestinationsVersion 中间目的地。您必须在 TripStatus 枚举。

  • ENROUTE_TO_PICKUP
  • ARRIVED_AT_PICKUP
  • ENROUTE_TO_INTERMEDIATE_DESTINATION
  • ARRIVED_AT_INTERMEDIATE_DESTINATION
  • ENROUTE_TO_DROPOFF
  • COMPLETE

示例

以下后端集成示例演示了如何创建 已超过上车点,目前正在前往其第一个中转点 目标。

static final String PROJECT_ID = "my-rideshare-co-gcp-project";
static final String TRIP_ID = "multi-destination-trip-A";

String tripName = "providers/" + PROJECT_ID + "/trips/" + TRIP_ID;

// Get the trip object from either the Fleet Engine or storage.
Trip trip = …;

TripServiceBlockingStub tripService = TripService.newBlockingStub(channel);

// The trip settings to be updated.
Trip trip = Trip.newBuilder()
    // Trip status cannot return to a previous state once it has passed.
    .setTripStatus(TripStatus.ENROUTE_TO_INTERMEDIATE_DESTINATION)

    // Enroute to the first intermediate destination.
    .setIntermediateDestinationIndex(0)

    // You must provide an intermediate_destinations_version to ensure that you
    // have the same intermediate destinations list as the Fleet Engine.
    .setIntermediateDestinationsVersion(
         trip.getIntermediateDestinationsVersion())
    .build();

// The trip update request.
UpdateTripRequest updateTripRequest = UpdateTripRequest.newBuilder()
    .setName(tripName)
    .setTrip(trip)
    .setUpdateMask(
        FieldMask.newBuilder()
            .addPaths("trip_status")
            .addPaths("intermediate_destination_index")
            // intermediate_destinations_version must not be in the update mask.
            .build())
    .build();

// Error handling.
try {
  Trip updatedTrip =
      tripService.updateTrip(updateTripRequest);
} catch (StatusRuntimeException e) {
  Status s = e.getStatus();
  switch (s.getCode()) {
    case NOT_FOUND:            // The trip doesn't exist.
      break;
    case FAILED_PRECONDITION:  // Either the trip status is invalid, or the
                               // intermediate_destinations_version doesn't
                               // match the Fleet Engine’s.
      break;
    case PERMISSION_DENIED:
      break;
  }
  return;
}