Android Question Auto check current location to detect arrival at a particular site?

'origin or destination parameter can be placeID (pefixed by place_id:) or Lat,Lon
'origin =place_id:ChIJ3S-JXmauEmsRUcIaWtf4MzE       
'destination=41.43206,-81.38992

Public Sub GetRoutePolyPointsString(origin As String, destination As String) As ResumableSub
   
    Dim polyPoints As String
    Dim j As HttpJob
    j.Initialize("", Me)
    j.Download2("https://maps.googleapis.com/maps/api/directions/json", Array As String("origin", origin, "destination", destination,"key",GoogleApiKey))
'...............................................


Sub GetTripDistanceData(source As String, destination As String) As ResumableSub
    Dim travelduration, traveldistance As Int
   
    Dim j As HttpJob
    j.Initialize("", Me)
    j.Download2("https://maps.googleapis.com/maps/api/directions/json", Array As String("origin", source,"destination", destination,"key", GoogleApiKey))
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Dim parser As JSONParser
        parser.Initialize(j.GetString)
        Dim mapRoot As Map = parser.NextObject
        If mapRoot.Get("status") = "OK" Then
            Dim lstRoutes As List = mapRoot.Get("routes")
            For Each mapRoutes As Map In lstRoutes
                Dim lstLegs As List = mapRoutes.Get("legs")
                For Each mapLegs As Map In lstLegs
                    'start_address  = mLegs.Get("start_address")
                    'end_address = mLegs.Get("end_address")
                    Dim lstSteps As List = mapLegs.Get("steps")
                    For Each mapSteps As Map In lstSteps
                        Dim mapDuration As Map = mapSteps.Get("duration")
                        travelduration = travelduration + mapDuration.Get("value")    'as Meters
                        Dim mapDistance As Map = mapSteps.Get("distance")
                        traveldistance = traveldistance + mapDistance.Get("value")      'as Seconds
                    Next
                Next
            Next
            Dim TripDistance As TripDistanceType
            TripDistance.TravelDistance = traveldistance
            TripDistance.TravelDuration = travelduration
            Return TripDistance
        Else
            Log("Error: " & mapRoot.Get("status"))
        End If
    Else
        Log("Error!")
    End If
    j.Release
End Sub

Sub GetLatAndLonByPlaceID(PlaceID As String) As ResumableSub
   
    Dim Result() As Double = Array As Double(9999, 9999)
    Dim j As HttpJob
    j.Initialize("", Me)
    j.Download2("https://maps.googleapis.com/maps/api/geocode/json", Array As String("place_id", PlaceID, "key", GoogleApiKey))
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Dim parser As JSONParser
        parser.Initialize(j.GetString)
        Dim mapRoot As Map = parser.NextObject
        If mapRoot.Get("status") = "OK" Then
            Dim lstResults As List = mapRoot.Get("results")
            If lstResults.Size > 0 Then
                Dim mapFirst As Map = lstResults.Get(0)
                Dim mapGeometry As Map = mapFirst.Get("geometry")
                Dim mapLocation As Map = mapGeometry.Get("location")
                Result(0) = mapLocation.Get("lat")
                Result(1) = mapLocation.Get("lng")
            End If
        End If
    Else
        Log("Error!")
    End If
   
    j.Release
    Return Result
   
End Sub