The core component of Navmii SDK responsible for route navigation is NMRouteNavigator. This class provides the API to control the route navigation process, to get navigation information and guidance updates. The class is also able to handle the rerouting and the rerouting by traffic.
CREATING ROUTE NAVIGATOR
NMSdk class contains the
routeNavigator property providing access to the instance of NMRouteNavigator. The route navigator instance can be accessed only after the SDK was started.
USING ROUTE NAVIGATOR
Route navigator has different responsibilities all related to each other:
- route navigator performs navigation along the specified route. Route navigator gets GPS position updates internally, updates the route navigation state and notifies if any changes occur.
- route navigator is able to handle rerouting. This option is intended to ease handling the rerouting process for SDK user. If rerouting handling is enabled, navigator, once rerouting is required, notifies that rerouting has started, calculates a new route, starts navigating along the new route and notifies that new route navigation has started.
- route navigator is able to handle rerouting by traffic. This option is intended to ease handing the rerouting by traffic process for SDK user. If rerouting by traffic is enabled, navigator, once traffic has been updated, applies it to the current route, if possible, or builds a new route otherwise, builds alternative routes if possible, and notifies that new route navigation has started, traffic was updated and alternative routes are available.
- route navigator is able to visualize changes in route by emitting route visualizer requests. To achieve such a behaviour you need to connect the route visualizer (
routeVisualizer property of NMSdk) to route navigator using
addRouteVisualizerRequestListener: method of NMRouteNavigator.
Route navigation starts by calling the
startNavigatingTheRoute: method. The
route parameter is an instance of NMRoute class which represents a route to navigate. The source of routes is Routing Service. After the route navigation has started, the route navigator gets GPS position updates internally, updates the route navigation state and notifies if any changes occur. Those "notifications" can be gotten by conforming to NMRouteNavigationListener protocol. Callbacks for the following events are available:
- the 'on-route state' changes: user has got off the route or got back on the route. The SDK user may need this information to handle rerouting manually;
- position on route (distance or time to destination) changes;
- the next direction information or distance to the next direction changes;
- a waypoint has been passed or destination has been reached.
Route navigator has properties to access the latest route navigation information at any time.
Route navigator also provides the route navigation guidance whose callbacks can be gotten by conforming to NMGuidanceListener protocol.
User is able to stop the route navigation by calling the
AUTOMATIC REROUTING HANDLING
As mentioned above NMRouteNavigator is able to handle rerouting automatically. The feature is enabled by default, but NMRouteNavigator class has the
reroutingEnabled property, which can be used to disable or enable the feature. If automatic rerouting handling is enabled, the route navigator tracks the on-route state and, once the GPS position has got off the route, calculates a new route and applies it. Callbacks about the automatic rerouting process can be gotten by conforming to NMReroutingListener protocol. The protocol has the
onReroutingStarted method, which is called once automatic rerouting starts, and the
onReroutingFinished: method, which is called once the process finishes. The
onReroutingFinished: method has the
newRoute parameter, which is a new instance of NMRoute class representing the new route being navigated. The
newRoute can be
nil if rerouting handling is no longer required (i.e. GPS position has returned back to the previous route).
The rerouting engine has an algorithm, which tries to use a route the most similar to the one passed to the
startNavigatingTheRoute: method. NMRouteNavigator has the
reroutingSettings property, which allows to tune the algorithm.
AUTOMATIC REROUTING BY TRAFFIC HANDLING
As mentioned above NMRouteNavigator is able to handle rerouting by traffic automatically. The feature is enabled by default, but NMRouteNavigator class has the
reroutingByTrafficEnabled property, which can be used to disable or enable the feature. If automatic rerouting by traffic is enabled, the route navigator internally gets notifications from the traffic service that traffic near the current position has been updated, and, once it happens, handles rerouting by traffic. The SDK user gets callbacks about the rerouting by traffic process by conforming to NMReroutingByTrafficListener protocol. The protocol has a single method, which is called once the rerouting by traffic occurred. Here is the method declaration:
newRoute:(nullable NMRoute *)newRoute
alternativeRoutes:(nullable NSArray<NMRoute *> *)alternativeRoutes;
The rerouting by traffic engine may create a new instance of NMRoute class. The
newRoute parameter will have non-null value if that happens. The
doesNewRouteResembleOldOne parameter indicates whether the route, being navigated after the rerouting by traffic occurred, is identical (takes the same roads) to the route being navigated before rerouting. So if the
newRoute is non-nil but the
YES means that the route being navigated hasn't changed (takes the same roads).
alternativeRoutes parameter is a list of alternative routes with the latest traffic applied, which can be used for navigation. Use
startNavigatingTheRoute: method to start navigation along one of the alternative routes.