Listen for navigation events

Page Summary

The Navigation SDK for iOS allows you to respond to real-time navigation events like route changes, arrival, and location updates using listeners.
GMSRoadSnappedLocationProviderListener and GMSNavigatorListener protocols handle events like location updates, speeding, and destination arrival.
Location updates can be managed for real-time tracking and background operation, impacting battery life.
The GMSNavigator provides methods to track and respond to waypoint arrivals, route changes, time and distance to destination, traffic flow, speeding percentage, and suggested lighting mode.
GMSNavigatorDelegate and GMSRoadSnappedLocationProviderDelegate are deprecated and replaced by GMSRoadSnappedLocationProviderListener and GMSNavigatorListener.

Use this guide to enable your app to listen and respond to a variety of events that change as a user navigates along a route. This guide does not cover defining a route, only responding to events along a route.

Overview

The Navigation SDK for iOS provides you with listeners associated with the location of the user and conditions along the route and important time and distance data. On the view controller of the map, your app needs to adopt the protocols for these listeners: GMSRoadSnappedLocationProviderListener and GMSNavigatorListener.

This list shows the listener methods available for navigation events:

GMSNavigatorListener.didArriveAtWaypoint, triggered when a destination is reached.
GMSNavigatorListener.navigatorDidChangeRoute, triggered when the route changes.
GMSNavigatorListener.didUpdateRemainingTime, called repeatedly as the time to the next destination changes, while guidance is active.
GMSNavigatorListener.didUpdateRemainingDistance, called repeatedly as the distance to the next destination changes, while guidance is active.
GMSNavigatorListener.didUpdateDelayCategory, called when the delay category to the next destination changes, while guidance is active.
GMSNavigatorListener.didChangeSuggestedLightingMode, triggered when the estimated lighting conditions are updated. For example when night falls at the user's current location the lighting changes.
GMSNavigatorListener.didUpdateSpeedingPercentage, triggered when the driver is exceeding the speed limit.
GMSRoadSnappedLocationProviderListener.didUpdateLocation, called repeatedly as the user's location changes.

See the code

Show/Hide the Swift code for an event listener.

/*
 * Copyright 2020 Google Inc. All rights reserved.
 *
 * 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
 *
 *      http://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 GoogleNavigation
import UIKit

class ViewController: UIViewController,
  GMSNavigatorListener,
  GMSRoadSnappedLocationProviderListener
{

  var mapView: GMSMapView!
  var locationManager: CLLocationManager!

  override func loadView() {

    locationManager = CLLocationManager()

    let camera = GMSCameraPosition.camera(withLatitude: 47.67, longitude: -122.20, zoom: 14)
    mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)

    // Add listeners for GMSNavigator and GMSRoadSnappedLocationProvider.
    mapView.navigator?.add(self)
    mapView.roadSnappedLocationProvider?.add(self)

    // Set the time update threshold (seconds) and distance update threshold (meters).
    mapView.navigator?.timeUpdateThreshold = 10
    mapView.navigator?.distanceUpdateThreshold = 100

    // Show the terms and conditions.
    let companyName = "Ride Sharing Co."
    GMSNavigationServices.showTermsAndConditionsDialogIfNeeded(
      withCompanyName: companyName
    ) { termsAccepted in
      if termsAccepted {
        // Enable navigation if the user accepts the terms.
        self.mapView.isNavigationEnabled = true

        // Request authorization to use location services.
        self.locationManager.requestAlwaysAuthorization()

        // Request authorization for alert notifications which deliver guidance instructions
        // in the background.
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert]) {
          granted, error in
          // Handle denied authorization to display notifications.
          if !granted || error != nil {
            print("Authorization to deliver notifications was rejected.")
          }
        }
      } else {
        // Handle the case when the user rejects the terms and conditions.
      }
    }

    view = mapView

    makeButton()
  }

  // Create a route and start guidance.
  @objc func startNav() {
    var destinations = [GMSNavigationWaypoint]()
    destinations.append(
      GMSNavigationWaypoint.init(
        placeID: "ChIJnUYTpNASkFQR_gSty5kyoUk",
        title: "PCC Natural Market")!)
    destinations.append(
      GMSNavigationWaypoint.init(
        placeID: "ChIJJ326ROcSkFQRBfUzOL2DSbo",
        title: "Marina Park")!)

    mapView.navigator?.setDestinations(destinations) { routeStatus in
      guard routeStatus == .OK else {
        print("Handle route statuses that are not OK.")
        return
      }
      self.mapView.navigator?.isGuidanceActive = true
      self.mapView.cameraMode = .following
      self.mapView.locationSimulator?.simulateLocationsAlongExistingRoute()
    }

    mapView.roadSnappedLocationProvider?.startUpdatingLocation()
  }

  // Listener to handle continuous location updates.
  func locationProvider(
    _ locationProvider: GMSRoadSnappedLocationProvider,
    didUpdate location: CLLocation
  ) {
    print("Location: \(location.description)")
  }

  // Listener to handle speeding events.
  func navigator(
    _ navigator: GMSNavigator, didUpdateSpeedingPercentage percentageAboveLimit: CGFloat
  ) {
    print("Speed is \(percentageAboveLimit) above the limit.")
  }

  // Listener to handle arrival events.
  func navigator(_ navigator: GMSNavigator, didArriveAt waypoint: GMSNavigationWaypoint) {
    print("You have arrived at: \(waypoint.title)")
    mapView.navigator?.continueToNextDestination()
    mapView.navigator?.isGuidanceActive = true
  }

  // Listener for route change events.
  func navigatorDidChangeRoute(_ navigator: GMSNavigator) {
    print("The route has changed.")
  }

  // Listener for time to next destination.
  func navigator(_ navigator: GMSNavigator, didUpdateRemainingTime time: TimeInterval) {
    print("Time to next destination: \(time)")
  }

  // Delegate for distance to next destination.
  func navigator(
    _ navigator: GMSNavigator,
    didUpdateRemainingDistance distance: CLLocationDistance
  ) {
    let miles = distance * 0.00062137
    print("Distance to next destination: \(miles) miles.")
  }

  // Delegate for traffic updates to next destination
  func navigator(
    _ navigator: GMSNavigator,
    didUpdate delayCategory: GMSNavigationDelayCategory
  ) {
    print("Delay category to next destination: \(String(describing: delayCategory)).")
  }

  // Delegate for suggested lighting mode changes.
  func navigator(
    _ navigator: GMSNavigator,
    didChangeSuggestedLightingMode lightingMode: GMSNavigationLightingMode
  ) {
    print("Suggested lighting mode has changed: \(String(describing: lightingMode))")

    // Change to the suggested lighting mode.
    mapView.lightingMode = lightingMode
  }

  // Add a button to the view.
  func makeButton() {
    // Start navigation.
    let navButton = UIButton(frame: CGRect(x: 5, y: 150, width: 200, height: 35))
    navButton.backgroundColor = .blue
    navButton.alpha = 0.5
    navButton.setTitle("Start navigation", for: .normal)
    navButton.addTarget(self, action: #selector(startNav), for: .touchUpInside)
    self.mapView.addSubview(navButton)
  }

}

Show/Hide the Objective-C code for an event listener.

/*
 * Copyright 2020 Google Inc. All rights reserved.
 *
 * 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
 *
 *      http://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 "ViewController.h"
@import GoogleNavigation;

@interface ViewController () <GMSNavigatorListener, GMSRoadSnappedLocationProviderListener>

@end

@implementation ViewController {
  GMSMapView *_mapView;
  CLLocationManager *_locationManager;
}

- (void)loadView {

  _locationManager = [[CLLocationManager alloc] init];

  GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:47.67
                                                          longitude:-122.20
                                                               zoom:14];
  _mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];

  // Add listeners for GMSNavigator and GMSRoadSnappedLocationProvider.
  [_mapView.navigator addListener:self];
  [_mapView.roadSnappedLocationProvider addListener:self];

  // Set the time update threshold (seconds) and distance update threshold (meters).
  _mapView.navigator.timeUpdateThreshold = 10;
  _mapView.navigator.distanceUpdateThreshold = 100;

  // Show the terms and conditions.
  NSString *companyName = @"Ride Sharing Co.";
  [GMSNavigationServices
   showTermsAndConditionsDialogIfNeededWithCompanyName:companyName
                                              callback:^(BOOL termsAccepted) {
     if (termsAccepted) {
       // Enable navigation if the user accepts the terms.
       _mapView.navigationEnabled = YES;

       // Request authorization to use location services.
       [_locationManager requestAlwaysAuthorization];

     } else {
       // Handle the case when the user rejects the terms and conditions.
     }
   }];

  self.view = _mapView;

  [self makeButton];
}

// Create a route and initiate navigation.
- (void)startNav {
  NSArray<GMSNavigationWaypoint *> *destinations =
  @[[[GMSNavigationWaypoint alloc] initWithPlaceID:@"ChIJnUYTpNASkFQR_gSty5kyoUk"
                                             title:@"PCC Natural Market"],
    [[GMSNavigationWaypoint alloc] initWithPlaceID:@"ChIJJ326ROcSkFQRBfUzOL2DSbo"
                                             title:@"Marina Park"]];

  [_mapView.navigator setDestinations:destinations
                             callback:^(GMSRouteStatus routeStatus){
                               _mapView.navigator.guidanceActive = YES;
                               _mapView.navigator.sendsBackgroundNotifications = YES;
                               _mapView.cameraMode = GMSNavigationCameraModeFollowing;
                               [_mapView.locationSimulator simulateLocationsAlongExistingRoute];
                             }];

  [_mapView.roadSnappedLocationProvider startUpdatingLocation];
}

#pragma mark - GMSNavigatorListener
// Listener for continuous location updates.
- (void)locationProvider:(GMSRoadSnappedLocationProvider *)locationProvider
      didUpdateLocation:(CLLocation *)location {
  NSLog(@"Location: %@", location.description);
}

// Listener to handle speeding events.
- (void)navigator:(GMSNavigator *)navigator
    didUpdateSpeedingPercentage:(CGFloat)percentageAboveLimit {
  NSLog(@"Speed is %f percent above the limit.", percentageAboveLimit);
}

// Listener to handle arrival events.
- (void)navigator:(GMSNavigator *)navigator didArriveAtWaypoint:(GMSNavigationWaypoint *)waypoint {
  NSLog(@"You have arrived at: %@", waypoint.title);
  [_mapView.navigator continueToNextDestination];
  _mapView.navigator.guidanceActive = YES;
}

// Listener for route change events.
- (void)navigatorDidChangeRoute:(GMSNavigator *)navigator {
  NSLog(@"The route has changed.");
}

// Listener for time to next destination.
- (void)navigator:(GMSNavigator *)navigator didUpdateRemainingTime:(NSTimeInterval)time {
  NSLog(@"Time to next destination: %f", time);
}

// Listener for distance to next destination.
- (void)navigator:(GMSNavigator *)navigator
      didUpdateRemainingDistance:(CLLocationDistance)distance {
  double miles = distance * 0.00062137;
  NSLog(@"%@", [NSString stringWithFormat:@"Distance to next destination: %.2f.", miles]);
}

// Listener for traffic updates for next destination
- (void)navigator:(GMSNavigator *)navigator
    didUpdateDelayCategory:(GMSNavigationDelayCategory)delayCategory {
  NSLog(@"Delay category to next destination: %ld.", delayCategory);
}

// Listener for suggested lighting mode changes.
-(void)navigator:(GMSNavigator *)navigator
      didChangeSuggestedLightingMode:(GMSNavigationLightingMode)lightingMode {
  NSLog(@"Suggested lighting mode has changed: %ld", (long)lightingMode);

  // Change to the suggested lighting mode.
  _mapView.lightingMode = lightingMode;
}

#pragma mark - Programmatic UI elements

// Add a button to the view.
- (void)makeButton {
  // Start navigation.
  UIButton *navButton = [UIButton buttonWithType:UIButtonTypeCustom];
  [navButton addTarget:self
                action:@selector(startNav)
      forControlEvents:UIControlEventTouchUpInside];
  [navButton setTitle:@"Navigate" forState:UIControlStateNormal];
  [navButton setBackgroundColor:[UIColor blueColor]];
  [navButton setAlpha:0.5];
  navButton.frame = CGRectMake(5.0, 150.0, 100.0, 35.0);
  [_mapView addSubview:navButton];
}

@end

Declaring conformance to the required protocols

Before implementing the navigation methods, the view controller must adopt the protocols:

Swift

class ViewController:
  UIViewController,
  GMSNavigatorListener,
  GMSRoadSnappedLocationProviderListener
{
}

Location property	Description
altitude	Current altitude.
coordinate.latitude	Current road-snapped latitude coordinate.
coordinate.longitude	Current road-snapped longitude coordinate.
course	Current bearing in degrees.
speed	Current speed.
timestamp	Date/time of current reading.

Delay category	Description
GMSNavigationDelayCategoryNoData	0 - Unavailable, no data for traffic or :
	the route.
GMSNavigationDelayCategoryHeavy	1 - Heavy.
GMSNavigationDelayCategoryMedium	2 - Medium.
GMSNavigationDelayCategoryLight	3 - Light.

Listen for navigation events Stay organized with collections Save and categorize content based on your preferences.

Page Summary

Overview

See the code

Declaring conformance to the required protocols

Swift

Objective-C

Swift

Objective-C

Receiving or stopping location updates

Swift

Objective-C

Swift

Objective-C

Swift

Objective-C

Detecting arrival events

Swift

Objective-C

Receiving route change updates

Swift

Objective-C

Receiving time to destination updates

Swift

Objective-C

Swift

Objective-C

Receiving distance to destination updates

Swift

Objective-C

Swift

Objective-C

Receiving traffic updates

Swift

Objective-C

Receiving speeding updates

Swift

Objective-C

Changing suggested lighting mode

Swift

Objective-C

Listen for navigation events