清除谷歌地图路线中的路线

Question

我有一组从 XML 加载的标记；单击标记时，我会显示从当前位置到标记位置的方向。但是，我希望能够清除路线，最好是在用户点击不同的标记时。目前所有的路线一起出现。我不知道我在哪里搞砸了。我已经尝试过方向Display.setMap(null) 但这并没有清除它们。如果您注意到问题所在，请告诉我。谢谢你。

function loadGoogleMap(){
    // load google map
    var script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = 'https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false&' +
        'callback=MyMap';
    document.body.appendChild(script);
}


var map = ''

function MyMap(){

/* 

document.getElementById('finddate').value

 */

var im = 'http://www.robotwoods.com/dev/misc/bluecircle.png';
var CustomMarker = 'http://findmyyard.com/images/MarkerIcon.png';

if(navigator.geolocation){

    navigator.geolocation.getCurrentPosition(locate, noPos());
} else { 

noPos();

}

function locate(position){


      var directionsDisplay = new google.maps.DirectionsRenderer();
      var directionsService = new google.maps.DirectionsService();

    var myLatLng = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
    var mapOptions = {
      zoom: 12,
      center: myLatLng,
      mapTypeId: google.maps.MapTypeId.ROADMAP,
      zoomControl: false,
      streetViewControl: false,
      mapTypeControl: false,
      panControlOptions: { position: google.maps.ControlPosition.TOP_RIGHT},
      zoomControlOptions: { position: google.maps.ControlPosition.TOP_RIGHT }
    }
    var map = new google.maps.Map(document.getElementById('map-canvas'),
                                  mapOptions);
    var userMarker = new google.maps.Marker({
        position: myLatLng,
        map: map,
        icon: im
    });
var infoWindow = new google.maps.InfoWindow;



  // Change this depending on the name of your PHP file

    downloadUrl("phps/xmltest.php", function(data) {
    var xml = data.responseXML;         
    var markers = xml.documentElement.getElementsByTagName("marker");
    for (var i = 0; i < markers.length; i++) {
      var name = markers[i].getAttribute("name");
      var address = markers[i].getAttribute("address");
      var dt1 = markers[i].getAttribute("date1");
      var dt2 = markers[i].getAttribute("date2");
      var dt3 = markers[i].getAttribute("date3");
      var tm1 = markers[i].getAttribute("time1");
      var tm2 = markers[i].getAttribute("time2");
      var tm3 = markers[i].getAttribute("time3");
      var pid = markers[i].getAttribute("PID");
      var d = new Date();
      var raw = pid * d.getFullYear();
      var jshtml = '<a href='+'phps/info.php?raw='+ raw +'>More Info</a>'
      var html = "<b>" + name + "</b> <br/>" + "Date of Yard Sale: " + dt1 + '&nbsp;' + tm1 + '&nbsp;' + dt2 + '&nbsp;' + tm2 + '&nbsp;' + dt3 + '&nbsp;' + tm3 + '&nbsp;' + "<br/>" + address + "&nbsp;" + "Click this for: " + jshtml;
      var point = new google.maps.LatLng(
          parseFloat(markers[i].getAttribute("lat")),
          parseFloat(markers[i].getAttribute("lng")));
      var marker = new google.maps.Marker({
        map: map,
        position: point,
        icon: CustomMarker
      });



      bindInfoWindow(marker, map, infoWindow, html, directionsDisplay);
    }


   });




function bindInfoWindow(marker, map, infoWindow, html, directionsDisplay) {


  google.maps.event.addListener(marker, 'click', function() {
    infoWindow.setContent(html);
    infoWindow.open(map, marker, html);
    center: position;

     directionsDisplay.setMap(null)
    directionsDisplay.setDirections({routes: []});  
    directionsDisplay = null;   



                          directionsDisplay = new google.maps.DirectionsRenderer();
                          directionsDisplay.setMap(map)
                          var start = myLatLng;
                          var latitude = marker.getPosition().lat().toFixed(6) 
                          var longitude = marker.getPosition().lng().toFixed(6)
                          var end = new google.maps.LatLng(latitude, longitude);
                          var request = {
                            origin:start,
                            destination:end,
                            travelMode: google.maps.TravelMode.DRIVING
                          };
                          directionsService.route(request, function(result, status) {

                            if (status == google.maps.DirectionsStatus.OK) {

                                directionsDisplay.setMap(null)
                                directionsDisplay.setMap(map);  
                              directionsDisplay.setDirections(result);  

                            }
                          });


  });
}

function downloadUrl(url, callback) {
  var request = window.ActiveXObject ?
      new ActiveXObject('Microsoft.XMLHTTP') :
      new XMLHttpRequest;

  request.onreadystatechange = function() {
    if (request.readyState == 4) {
      request.onreadystatechange = doNothing;
      callback(request, request.status);
    }
  };


     request.open('GET', url, true);
  request.send();
}
     function doNothing() {}
}

Answer 1

不适合我 - 我需要这个：

// Clear past routes
    if (directionsDisplay != null) {
        directionsDisplay.setMap(null);
        directionsDisplay = null;
    }

Answer 2

现有的答案都不适合我。丢弃directionsDisplay 或调用setMap(null) 只是断开了DirectionsRenderer 与地图的连接。

而是保留DirectionsRenderer 实例，并调用directionsDisplay.set('directions', null); 来重置方向。

Answer 3

从点击回调中删除它：

directionsDisplay = new google.maps.DirectionsRenderer();

这一行总是会创建一个新的 DirectionsRenderer-instance，但是当您只想一次显示 1 条路线时，您只需要一个实例（已在 locate 中初始化）。

使用单个实例时无需清除任何内容。单个方向渲染器永远不会显示超过 1 条路线，一旦您调用 setDirections，之前绘制的路线将被自动删除。