我无法获得语音通知，这里的地图实时导航在应用程序开发的颤振。

Question

尝试了大量的代码，我可以导航的路线，但它并没有给我任何一种语音通知轮流左或右。

   void startNavigation1(Route route) {
_prepareNavigation(route);

// Stop in case it was started before.
_locationSimulationProvider.stop();

// Access the device's GPS sensor and other data.
// The navigator is set as listener to receive location updates.
_herePositioningProvider!.startLocating(_visualNavigator, LocationAccuracy.navigation);

_startDynamicSearchForBetterRoutes(route);
setupListeners2();

}

{print(‘ininsetuplistener2-)；( HERE.RouteProgressListener((HERE.RouteProgress routeProgress)异步{地图jsonData ={ "load"：load_info!.id，“卡车”：load_info!.truck_id，"load_size"："TL"，“令牌”：str_accesstoken!，"type"："GPS"，//"state"：'_currentAddress'，// "country"："US"，// "postal"："10001"，“位置”：{“坐标”：{ _herePositioningProvider！.getLastKnownLocation()！.coordinates .longitude，"lat"：_herePositioningProvider！.getLastKnownLocation()！.coordinates .latitude }，"type"："Point"，}；

  if (socket == null && (load_info!.status == 'Intransit' ||
      load_info!.status != 'Journey End')) {
    if (socket == null) {
      print(' inside socket');
      Socket? _socket =
      await SocketIOConnection()
          .connectToServer(
          str_accesstoken!);
      setState(() {
        socket = _socket;
      });
      socket!.connect();
      socket!.onConnect((data) {
        print('connected......');
        Timer.periodic(new Duration(seconds: 20), (timer) {
          socket!.emit("gps", jsonData);
        });
      });
    }

    // Timer mytimer = Timer.periodic(Duration(minutes:0, seconds: 15), (timer) async {
    //code to run on every 2 minutes 5 seconds
    // await SocketIOConnection().sendLocation(jsonData);
    // });

    // Timer.periodic(new Duration(seconds: 20), (timer) {
    //   print('connected inside');
    //   print(jsonData);

    // });

    // timer= new Timer(new Duration(seconds: 15), () async {
    //   debugPrint("Print after 15 seconds");
    // //  await SocketIOConnection().sendMessage(socket!, jsonData);
    //   await Future.delayed(Duration(milliseconds: 10000));
    //   await SocketIOConnection().sendLocation(jsonData);
    // await Future.delayed(Duration(milliseconds: 10000));
    //
    // });
    // Timer.periodic(new Duration(seconds: 1), (timer) {
    //   debugPrint(timer.tick.toString());
    // });
    //


  }

  // Handle results from onRouteProgressUpdated():
  List<HERE.SectionProgress> sectionProgressList = routeProgress.sectionProgress;
  // sectionProgressList is guaranteed to be non-empty.
  HERE.SectionProgress lastSectionProgress = sectionProgressList.elementAt(sectionProgressList.length - 1);
  print('Distance to destination in meters: ' + lastSectionProgress.remainingDistanceInMeters.toString());
  //print('Traffic delay ahead in seconds: ' + lastSectionProgress.trafficDelay.inSeconds.toString());

  // Contains the progress for the next maneuver ahead and the next-next maneuvers, if any.
  List<HERE.ManeuverProgress> nextManeuverList = routeProgress.maneuverProgress;

  if (nextManeuverList.isEmpty) {
    print('No next maneuver available.');
    return;
  }





  HERE.ManeuverProgress nextManeuverProgress = nextManeuverList.first;

  int nextManeuverIndex = nextManeuverProgress.maneuverIndex;
  HERE.Maneuver? nextManeuver = _visualNavigator.getManeuver(nextManeuverIndex);
  if (nextManeuver == null) {
    // Should never happen as we retrieved the next maneuver progress above.
    return;
  }

  HERE.ManeuverAction action = nextManeuver.action;
  String roadName = _getRoadName(nextManeuver);
  String logMessage = describeEnum(action) +
      ' on ' +
      roadName +
      ' in ' +
      nextManeuverProgress.remainingDistanceInMeters.toString() +
      ' meters.';

  if (_previousManeuverIndex != nextManeuverIndex) {
    _updateMessageState('New maneuver: $logMessage');
  } else {
    // A maneuver update contains a different distance to reach the next maneuver.
    _updateMessageState("Maneuver update: $logMessage");
  }
  _previousManeuverIndex = nextManeuverIndex;

  if (_lastMapMatchedLocation != null) {
    // Update the route based on the current location of the driver.
    // We periodically want to search for better traffic-optimized routes.
    _dynamicRoutingEngine.updateCurrentLocation(_lastMapMatchedLocation!, routeProgress.sectionIndex);
  }


  if (str_action != 'Truck Location' ||
      str_action != 'Truck Drop Location') {
    // button_text == 'Check In Truck Location';
    // setState(() {
    //   flag3 = 1;
    // });
  } else {
    if (double.parse(str_distance!) <= 2) {
      SetTracking? setTracking =
      // await GetTracking(str_accesstoken, str_user_id)
      await GetTracking(str_accesstoken,context)
          .GetTrackingDetails();
      setState(() {
        _setTracking = setTracking!;
        button_color = _setTracking!.button_color;
        button_text = _setTracking!.button_text;
      });
      if (button_text == 'Check In') {
        setState(() {
          flag5=1;
          flag3 = 1;
        });
      } else if (button_text == 'Check Out') {
        setState(() {
          flag5=1;
          flag3 = 1;
        });
      } else if (button_text == 'Hook Now') {
        setState(() {
          flag3 = 1;
        });
      } else if (button_text == 'Drop Now') {
        setState(() {
          flag3 = 1;
        });
      }
    }
  }

  // Contains the progress for the next maneuver ahead and the next-next maneuvers, if any.
  // Contains the progress for the next maneuver ahead and the next-next maneuvers, if any.
  setState(() {
    maneuver_action =
        _visualNavigator.getManeuver(nextManeuverIndex)!.action.toString();
    str_direction = logMessage;
  });
  if (_previousManeuverIndex != nextManeuverIndex) {
    print('New maneuver: $logMessage');
  } else {
    // A maneuver update contains a different distance to reach the next maneuver.
    print('Maneuver update: $logMessage');
  }

});
// Notifies on voice maneuver messages.
_visualNavigator.maneuverNotificationListener = HERE.ManeuverNotificationListener((String voiceText) async {
  // Handle results lambda_onManeuverNotification().
  // Flutter itself does not provide a text-to-speech engine. Use one of the available TTS plugins to speak
  // the voiceText message.
  print("Voice guidance text: $voiceText");
  // setState(() async {
  maneuver_icon = getManeuveraction(maneuver_action!);
  print('icon :' + maneuver_icon!);
  await flutterTts.setSpeechRate(1.0);

  await flutterTts.setVolume(1.0);

  await flutterTts.setPitch(1.0);
  await flutterTts.synthesizeToFile("Hello World", Platform.isAndroid ? "tts.wav" : "tts.caf");

  await flutterTts.setVoice({"name": "Karen", "locale": "en-AU"});
  await flutterTts.isLanguageAvailable("en-US");
  await flutterTts.speak(voiceText);

  // flutterTts.speak(voiceText);
  // flutterTts.setVolume(150);
  // });

});
// Notifies on the current map-matched location and other useful information while driving or walking.
// The map-matched location is used to update the map view.
_visualNavigator.navigableLocationListener =
    HERE.NavigableLocationListener((HERE.NavigableLocation currentNavigableLocation) {
      // Handle results from onNavigableLocationUpdated():
      HERE.MapMatchedLocation? mapMatchedLocation = currentNavigableLocation.mapMatchedLocation;
      if (mapMatchedLocation == null) {
        print("This new location could not be map-matched. Are you off-road?");
        return;
      }

      _lastMapMatchedLocation = mapMatchedLocation;

      var speed = currentNavigableLocation.originalLocation.speedInMetersPerSecond;
      var accuracy = currentNavigableLocation.originalLocation.speedAccuracyInMetersPerSecond;
      print("Driving speed (m/s): $speed plus/minus an accuracy of: $accuracy");
    });

// Notifies when the destination of the route is reached.
_visualNavigator.destinationReachedListener = HERE.DestinationReachedListener(() {


  // Handle results from onDestinationReached().
  _updateMessageState("Destination reached. Stopping turn-by-turn navigation.");
  // Handle r
  print('Destination reached. Stopping turn-by-turn navigation.');
  print('str_action on destination reached:'+str_action.toString());
  if (str_action == 'Truck Location')
    // &&
    // str_action != 'Truck Drop Location')
      {
    setState(() {
      flag2 = 1;
      flag1=0;
      flag5=1;
      // flag3=0;
      str_next_consignment='Reached Truck Location';
    });
    if(socket!=null){
      socket!.disconnect();
      socket!.ondisconnect();
      print('......disconnected');
    }
    _settingModalBottomSheet();
  }
  else  if (str_action == 'Pickup')
    // &&
    // str_action != 'Truck Drop Location')
      {
    setState(() {
      // flag2 = 1;
      // flag2 = 0;
      // flag1 = 0;
      flag5=1;
      button_text = 'Check In';
      flag3 = 1;

      str_next_consignment='Reached Pickup Location';
      //button_text = 'Check In';
      // endflag=1;

    });
    if(socket!=null){
      socket!.disconnect();
      socket!.ondisconnect();
      print('......disconnected');
    }
    _settingModalBottomSheet();
  }
  else  if (str_action == 'Dropoff')
    // &&
    // str_action != 'Truck Drop Location')
      {
    setState(() {
      // flag2 = 0;
      // flag1 = 0;
      flag5=1;
      button_text = 'Check In';
      flag3 = 1;
      //flag2 = 1;


      str_next_consignment='Reached Dropoff Location';
      // button_text = 'Check In';
      // endflag=1;

    });
    if(socket!=null){
      socket!.disconnect();
      socket!.ondisconnect();
      print('......disconnected');
    }
    _settingModalBottomSheet();
  }
  else if (str_action == 'Truck End Location')
    // &&
    // str_action != 'Truck Drop Location').
      {
    Map data =
    {
      'load': load_info!.id,
      'event': 'Dropped Truck',
      "truck":load_info!.truck_id

    };
    UpdateJourneyStatus(data);
    print('data:'+data.toString());
    setState(() {
      str_next_consignment='Reached Truck End Location';
      flag1=0;
      flag5=1;
      endflag=1;
    }

    );
    if(endflag==1)
    {
      _selectendtrip();
    }
  }
  // else {
  //   setState(() {
  //     button_text = 'Check In';
  //    // endflag=1;
  //     flag3 = 1;
  //   });
  //   // if(endflag==1)
  //   // {
  //   //   _selectendtrip();
  //   // }
  // }
  if (socket != null)
  {
    socket!.onDisconnect((data) => print('disconnected'));
  }
  stopNavigation();

});


// Notifies when a waypoint on the route is reached or missed

// _visualNavigator.milestoneStatusListener = MilestoneStatusListener((Milestone milestone, MilestoneStatus milestoneStatus) {
//   // Handle results from onMilestoneStatusUpdated().
//   if (milestone.waypointIndex != null && milestoneStatus == MilestoneStatus.reached) {
//     print("A user-defined waypoint was reached, index of waypoint: " + milestone.waypointIndex.toString());
//     print("Original coordinates: " + milestone.originalCoordinates.toString());
//   } else if (milestone.waypointIndex != null && milestoneStatus == MilestoneStatus.missed) {
//     print("A user-defined waypoint was missed, index of waypoint: " + milestone.waypointIndex.toString());
//     print("Original coordinates: " + milestone.originalCoordinates.toString());
//   } else if (milestone.waypointIndex == null && milestoneStatus == MilestoneStatus.reached) {
//     // For example, when transport mode changes due to a ferry a system-defined waypoint may have been added.
//     print("A system-defined waypoint was reached at: " + milestone.mapMatchedCoordinates.toString());
//   } else if (milestone.waypointIndex == null && milestoneStatus == MilestoneStatus.reached) {
//     // For example, when transport mode changes due to a ferry a system-defined waypoint may have been added.
//     print("A system-defined waypoint was missed at: " + milestone.mapMatchedCoordinates.toString());
//   }
// });

// Notifies on the current speed limit valid on the current road.
_visualNavigator.speedLimitListener = HERE.SpeedLimitListener((HERE.SpeedLimit speedLimit) {
  // Handle results from onSpeedLimitUpdated().
  double? currentSpeedLimit = _getCurrentSpeedLimit(speedLimit);

  if (currentSpeedLimit == null) {
    print("Warning: Speed limits unknown, data could not be retrieved.");
  } else if (currentSpeedLimit == 0) {
    print("No speed limits on this road! Drive as fast as you feel safe ...");
  } else {
    print("Current speed limit (m/s): $currentSpeedLimit");
  }
});

// Notifies when the current speed limit is exceeded.
_visualNavigator.speedWarningListener = HERE.SpeedWarningListener((HERE.SpeedWarningStatus speedWarningStatus) {
  // Handle results from onSpeedWarningStatusChanged().
  if (speedWarningStatus == HERE.SpeedWarningStatus.speedLimitExceeded) {
    // Driver is faster than current speed limit (plus an optional offset, see setupSpeedWarnings()).
    // Play a click sound to indicate this to the driver.
    // As Flutter itself does not provide support for sounds,
    // alternatively use a 3rd party plugin to play an alert sound of your choice.
    // Note that this may not include temporary special speed limits, see SpeedLimitListener.
    SystemSound.play(SystemSoundType.click);
    print("Speed limit exceeded.");
  }

  if (speedWarningStatus == HERE.SpeedWarningStatus.speedLimitRestored) {
    print("Driver is again slower than current speed limit (plus an optional offset.)");
  }
});

// Notifies on a possible deviation from the route.
// When deviation is too large, an app may decide to recalculate the route from current location to destination.
_visualNavigator.routeDeviationListener = HERE.RouteDeviationListener((HERE.RouteDeviation routeDeviation) {
  // Handle results from onRouteDeviation().
  HERE.Route? route = _visualNavigator.route;
  if (route == null) {
    // May happen in rare cases when route was set to null inbetween.
    return;
  }

  // Get current geographic coordinates.
  HERE.MapMatchedLocation? currentMapMatchedLocation = routeDeviation.currentLocation.mapMatchedLocation;
  GeoCoordinates currentGeoCoordinates = currentMapMatchedLocation == null
      ? routeDeviation.currentLocation.originalLocation.coordinates
      : currentMapMatchedLocation.coordinates;

  // Get last geographic coordinates on route.
  GeoCoordinates lastGeoCoordinatesOnRoute;
  if (routeDeviation.lastLocationOnRoute != null) {
    HERE.MapMatchedLocation? lastMapMatchedLocationOnRoute = routeDeviation.lastLocationOnRoute!.mapMatchedLocation;
    lastGeoCoordinatesOnRoute = lastMapMatchedLocationOnRoute == null
        ? routeDeviation.lastLocationOnRoute!.originalLocation.coordinates
        : lastMapMatchedLocationOnRoute.coordinates;
  } else {
    print("User was never following the route. So, we take the start of the route instead.");
    lastGeoCoordinatesOnRoute = route.sections.first.departurePlace.originalCoordinates!;
  }

  int distanceInMeters = currentGeoCoordinates.distanceTo(lastGeoCoordinatesOnRoute) as int;
  print("RouteDeviation in meters is " + distanceInMeters.toString());
});

// // Notifies on voice maneuver messages.
// _visualNavigator.maneuverNotificationListener = HERE.ManeuverNotificationListener((String voiceText) async {
//   // Handle results lambda_onManeuverNotification().
//   // Flutter itself does not provide a text-to-speech engine. Use one of the available TTS plugins to speak
//   // the voiceText message.
//   print("Voice guidance text: $voiceText");
//   // setState(() async {
//     maneuver_icon = getManeuveraction(maneuver_action!);
//     print('icon :' + maneuver_icon!);
//     await flutterTts.setSpeechRate(1.0);
//
//     await flutterTts.setVolume(1.0);
//
//     await flutterTts.setPitch(1.0);
//    await flutterTts.synthesizeToFile("Hello World", Platform.isAndroid ? "tts.wav" : "tts.caf");
//
//    await flutterTts.setVoice({"name": "Karen", "locale": "en-AU"});
//     await flutterTts.isLanguageAvailable("en-US");
//     await flutterTts.speak(voiceText);
//
//     // flutterTts.speak(voiceText);
//     // flutterTts.setVolume(150);
//   // });
//
// });

// Notifies on the attributes of the current road including usage and physical characteristics.
_visualNavigator.roadAttributesListener = HERE.RoadAttributesListener((HERE.RoadAttributes roadAttributes) {
  // Handle results from onRoadAttributesUpdated().
  // This is called whenever any road attribute has changed.
  // If all attributes are unchanged, no new event is fired.
  // Note that a road can have more than one attribute at the same time.
  print("Received road attributes update.");

  if (roadAttributes.isBridge) {
    // Identifies a structure that allows a road, railway, or walkway to pass over another road, railway,
    // waterway, or valley serving map display and route guidance functionalities.
    print("Road attributes: This is a bridge.");
  }
  if (roadAttributes.isControlledAccess) {
    // Controlled access roads are roads with limited entrances and exits that allow uninterrupted
    // high-speed traffic flow.
    print("Road attributes: This is a controlled access road.");
  }
  if (roadAttributes.isDirtRoad) {
    // Indicates whether the navigable segment is paved.
    print("Road attributes: This is a dirt road.");
  }
  if (roadAttributes.isDividedRoad) {
    // Indicates if there is a physical structure or painted road marking intended to legally prohibit
    // left turns in right-side driving countries, right turns in left-side driving countries,
    // and U-turns at divided intersections or in the middle of divided segments.
    print("Road attributes: This is a divided road.");
  }
  if (roadAttributes.isNoThrough) {
    // Identifies a no through road.
    print("Road attributes: This is a no through road.");
  }
  if (roadAttributes.isPrivate) {
    // Private identifies roads that are not maintained by an organization responsible for maintenance of
    // public roads.
    print("Road attributes: This is a private road.");
  }
  if (roadAttributes.isRamp) {
    // Range is a ramp: connects roads that do not intersect at grade.
    print('Road attributes: This is a ramp.');
  }
  if (roadAttributes.isRightDrivingSide) {
    // Indicates if vehicles have to drive on the right-hand side of the road or the left-hand side.
    // For example, in New York it is always true and in London always false as the United Kingdom is
    // a left-hand driving country.
    print("Road attributes: isRightDrivingSide = " + roadAttributes.isRightDrivingSide.toString());
  }
  if (roadAttributes.isRoundabout) {
    // Indicates the presence of a roundabout.
    print("Road attributes: This is a roundabout.");
  }
  if (roadAttributes.isTollway) {
    // Identifies a road for which a fee must be paid to use the road.
    print("Road attributes change: This is a road with toll costs.");
  }
  if (roadAttributes.isTunnel) {
    // Identifies an enclosed (on all sides) passageway through or under an obstruction.
    print("Road attributes: This is a tunnel.");
  }
});

// Notifies which lane(s) lead to the next (next) maneuvers.
_visualNavigator.maneuverViewLaneAssistanceListener =
    HERE.ManeuverViewLaneAssistanceListener((HERE.ManeuverViewLaneAssistance laneAssistance) {
      // Handle events from onLaneAssistanceUpdated().
      // This lane list is guaranteed to be non-empty.
      List<HERE.Lane> lanes = laneAssistance.lanesForNextManeuver;
      logLaneRecommendations(lanes);

      List<HERE.Lane> nextLanes = laneAssistance.lanesForNextNextManeuver;
      if (nextLanes.isNotEmpty) {
        print("Attention, the next next maneuver is very close.");
        print("Please take the following lane(s) after the next maneuver: ");
        logLaneRecommendations(nextLanes);
      }
    });

// Notifies which lane(s) allow to follow the route.
_visualNavigator.junctionViewLaneAssistanceListener =
    HERE.JunctionViewLaneAssistanceListener((HERE.JunctionViewLaneAssistance junctionViewLaneAssistance) {
      List<HERE.Lane> lanes = junctionViewLaneAssistance.lanesForNextJunction;
      if (lanes.isEmpty) {
        _updateMessageState("You have passed the complex junction.");
      } else {
        _updateMessageState("Attention, a complex junction is ahead.");
        logLaneRecommendations(lanes);
      }
    });

// Notifies truck drivers on road restrictions ahead.
// For example, there can be a bridge ahead not high enough to pass a big truck
// or there can be a road ahead where the weight of the truck is beyond it's permissible weight.
// This event notifies on truck restrictions in general,
// so it will also deliver events, when the transport type was set to a non-truck transport type.
// The given restrictions are based on the HERE database of the road network ahead.
_visualNavigator.truckRestrictionsWarningListener =
    HERE.TruckRestrictionsWarningListener((List<HERE.TruckRestrictionWarning> list) {
      // The list is guaranteed to be non-empty.
      for (HERE.TruckRestrictionWarning truckRestrictionWarning in list) {
        if (truckRestrictionWarning.distanceType == HERE.DistanceType.ahead) {
          print("TruckRestrictionWarning ahead in: ${truckRestrictionWarning.distanceInMeters} meters.");
        } else if (truckRestrictionWarning.distanceType == HERE.DistanceType.passed) {
          print("A restriction just passed.");
        }
        // One of the following restrictions applies ahead, if more restrictions apply at the same time,
        // they are part of another TruckRestrictionWarning element contained in the list.
        if (truckRestrictionWarning.weightRestriction != null) {
          // For now only one weight type (= truck) is exposed.
          HERE.WeightRestrictionType type = truckRestrictionWarning.weightRestriction!.type;
          int value = truckRestrictionWarning.weightRestriction!.valueInKilograms;
          print("TruckRestriction for weight (kg): ${type.toString()}: $value");
        }
        if (truckRestrictionWarning.dimensionRestriction != null) {
          // Can be either a length, width or height restriction of the truck. For example, a height
          // restriction can apply for a tunnel. Other possible restrictions are delivered in
          // separate TruckRestrictionWarning objects contained in the list, if any.
          HERE.DimensionRestrictionType type = truckRestrictionWarning.dimensionRestriction!.type;
          int value = truckRestrictionWarning.dimensionRestriction!.valueInCentimeters;
          print("TruckRestriction for dimension: ${type.toString()}: $value");
        }
      }
    });

// Notifies whenever any textual attribute of the current road changes, i.e., the current road texts differ
// from the previous one. This can be useful during tracking mode, when no maneuver information is provided.
_visualNavigator.roadTextsListener = HERE.RoadTextsListener((HERE.RoadTexts roadTexts) {
  // See _getRoadName() how to get the current road name from the provided RoadTexts.
});

}

Answer 1

这里的SDK本身不提供任何机制来播放TTS声音。它只提示文本消息，然后可以用来“说话”文本。如果您的应用程序收到了这些提示，那么这是一个与您的TTS实现相关的问题。

如果你使用一个颤振的TTS插件，试着创建一个孤立的例子，听它是否会说任何文字。

设备的设置也可能出现问题。如果有疑问，请在这里执行SDK 示例应用程序：如果设备设置正确，您将听到语音消息。