Going Offroute with the GraphHopper sample crashes the app

[boldtrn]

Right now the GraphHopper sample has no logic to catch reroute events and send these new requests again to the GraphHopper routing server. Right now the rerouting will be send to Mapbox using their directions API. If you don't have a Mapbox key, the app will crash.

[stroggsystems-oss]

Hello!

Yes, I have the same problem. I just tested my application with GraphHopper, and every time I change routes, the application crashes.

[stroggsystems-oss]

Hello there!!!,
After two days of researching the code for the “libandroid-navigation-ui” module (I am a Java developer with very little experience), I found a possible solution to this problem:

At this point, we have two issues:

• The navigation user interface uses “MapboxDirections” to create a valid navigation route (“NavigationRoute”) during route recalculation.
• I don't know if this problem only affects me, but the latitude and longitude coordinates of the start and destination points are reversed, which causes an error every time the MapBox library makes a request to GraphHopper (“message Point 1 is too far from point 0”).

For the first issue, I made some changes to the ‘findRouteWith’ method in the ‘MapLibreRouteFetcher’ class:

It is possible to set the base URL and override the default URL of the MapBox API: https://docs.mapbox.com/android/java/api/libjava-services/5.8.0/com/mapbox/api/directions/v5/MapboxDirections.html

Setting builder.baseURL to ‘https://graphhopper.com/api/1/navigate/’ works for me.

builder.baseUrl("https://graphhopper.com/api/1/navigate/");

The other change we need to make is to set ‘accessToken’ and ‘user’ to:

builder.accessToken("pk.<GraphHopperToken>");
builder.user("gh");

NOTE: The accessToken must start with ‘pk.’.

More Info: graphhopper/graphhopper-navigation-example#1

In addition, I have added a try/catch block to handle possible exceptions and prevent the application from crashing.

The second issue drove me crazy. I needed to swap the latitude and longitude of the origin and destination points. I don't know why, but with this swap (latitude for longitude and longitude for latitude), the GraphHopper API works fine and I get a new route every time I need a new calculation.

I made this change in the ‘buildRequest’ method of the same class.

Because we are coding some adjustments, I am sure we are breaking integration with other providers, such as Valhalla and MapBox.

After making the modifications, integration with GrahHooper works, at least on the Android device emulator.

I hope this helps.