Google Maps JavaScript API - Show INACTIVE Alternative Routes In One Color, ACTIVE Alternative Route In Another

I am using the Google Maps JavaScript API and am providing directions with alternative routes. I would like to display the INACTIVE alternative routes in a gray color, and the curr

Solution 1:

When you "activate" a route, process through the array of polylines:

1. set the strokeColor of all the routes to 'grey'
2. set the active route's polyline color to the "active" color

proof of concept fiddle (based on my example which you reference, click on the polyline to "activate" it)

code snippet:

$(document).ready(function() {
  var markers = [{
    "title": '',
    "lat": '56.965969',
    "lng": '24.143496',
    "description": ''
  }, {
    "title": '',
    "lat": '56.966259',
    "lng": '24.385860',
    "description": ''
  }];
  var service = new google.maps.DirectionsService();
  var polyArray = [];
  var infoWindow = new google.maps.InfoWindow();
  var map = new google.maps.Map(document.getElementById("map_1"), mapOptions);
  var lat_lng = new Array();
  var colors = ['#ff0000', '#00ff00', '#0000ff', '#ffff00', '#ff00ff', '#00ffff'];
  var image = 'https://maps.google.com/mapfiles/ms/micons/blue.png';
  var marker = new google.maps.Marker({
    position: new google.maps.LatLng(56.966259, 24.385860),
    map: map,
    title: 'Sillava',
    icon: image
  });
  for (i = 0; i < markers.length; i++) {
    var data = markers[i];
    var myLatlng = new google.maps.LatLng(data.lat, data.lng);
    lat_lng.push(myLatlng);
  }
  for (var i = 0; i < lat_lng.length; i++) {
    if ((i + 1) < lat_lng.length) {
      var src = lat_lng[i];
      var des = lat_lng[i + 1];
      service.route({
        origin: src,
        destination: des,
        provideRouteAlternatives: true,
        travelMode: google.maps.DirectionsTravelMode.DRIVING
      }, function(result, status) {
        if (status == google.maps.DirectionsStatus.OK) {
          for (var j = 0; j < result.routes.length; j++) {
            var path = new google.maps.MVCArray();
            polyArray.push(new google.maps.Polyline({
              map: map,
              strokeColor: "grey",
              strokeOpacity: 0.3,
              strokeWeight: 5
            }));
            if (j == 0) polyArray[0].setOptions({
              strokeColor: '#00ff00',
              strokeOpacity: 1.0
            });
            polyArray[polyArray.length - 1].setPath(path);
            google.maps.event.addListener(polyArray[polyArray.length - 1], 'click', function() {
              for (var i = 0; i < polyArray.length; i++) {
                polyArray[i].setOptions({
                  strokeOpacity: 0.3,
                  strokeColor: "grey"
                });
              }
              this.setOptions({
                strokeOpacity: 1.0,
                strokeColor: "#00ff00"
              });
            })
            for (var i = 0, len = result.routes[j].overview_path.length; i < len; i++) {
              path.push(result.routes[j].overview_path[i]);
            }
          }
        }
      });
    }
  }
});
var mapOptions = {
  zoom: 11,
  center: new google.maps.LatLng(56.975749, 24.279310),
  scrollwheel: false,
  navigationControl: false,
  mapTypeControl: false,
  scaleControl: false,
  draggable: false,
  styles: [{
    "featureType": "water",
    "elementType": "geometry",
    "stylers": [{
      "color": "#d3d3d3"
    }, {
      "lightness": 17
    }]
  }, {
    "featureType": "landscape",
    "elementType": "geometry",
    "stylers": [{
      "color": "#f5f5f5"
    }, {
      "lightness": 20
    }]
  }, {
    "featureType": "road.highway",
    "elementType": "geometry.fill",
    "stylers": [{
      "color": "#ffffff"
    }, {
      "lightness": 17
    }]
  }, {
    "featureType": "road.highway",
    "elementType": "geometry.stroke",
    "stylers": [{
      "color": "#ffffff"
    }, {
      "lightness": 29
    }, {
      "weight": 0.2
    }]
  }, {
    "featureType": "road.arterial",
    "elementType": "geometry",
    "stylers": [{
      "color": "#ffffff"
    }, {
      "lightness": 18
    }]
  }, {
    "featureType": "road.local",
    "elementType": "geometry",
    "stylers": [{
      "color": "#ffffff"
    }, {
      "lightness": 16
    }]
  }, {
    "featureType": "poi",
    "elementType": "geometry",
    "stylers": [{
      "color": "#f5f5f5"
    }, {
      "lightness": 21
    }]
  }, {
    "featureType": "poi.park",
    "elementType": "geometry",
    "stylers": [{
      "color": "#dedede"
    }, {
      "lightness": 21
    }]
  }, {
    "elementType": "labels.text.stroke",
    "stylers": [{
      "visibility": "on"
    }, {
      "color": "#ffffff"
    }, {
      "lightness": 16
    }]
  }, {
    "elementType": "labels.text.fill",
    "stylers": [{
      "saturation": 36
    }, {
      "color": "#333333"
    }, {
      "lightness": 40
    }]
  }, {
    "elementType": "labels.icon",
    "stylers": [{
      "visibility": "off"
    }]
  }, {
    "featureType": "transit",
    "elementType": "geometry",
    "stylers": [{
      "color": "#f2f2f2"
    }, {
      "lightness": 19
    }]
  }, {
    "featureType": "administrative",
    "elementType": "geometry.fill",
    "stylers": [{
      "color": "#fefefe"
    }, {
      "lightness": 20
    }]
  }, {
    "featureType": "administrative",
    "elementType": "geometry.stroke",
    "stylers": [{
      "color": "#fefefe"
    }, {
      "lightness": 17
    }, {
      "weight": 1.2
    }]
  }]
};

.map {
  width: 100%;
  height: 100%;
}
body,
html {
  height: 100%;
  width: 100%;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<div id="map_1" class="map"></div>