Question

我是Google Map API的新手。我知道这可能很简单。代码按需要工作，除了我无法获得最初在地图上显示的标记。标记正在等待单击事件以显示标记。当地图首次加载时，需要在地图上显示初始标记，以便可以拖动它。

<!DOCTYPE html>
<html>
    <head>
    <script type="text/javascript" charset="utf-8" src="libs/jq.ui.min.js"></script> 
    <script type="text/javascript"
      src="https://maps.googleapis.com/maps/api/js?libraries=geometry,places,visualization&sensor=false"></script>


 <script>
var initialLocation;
var map;
var marker;
var latlon;
var lat;
var lon;


     //---------------------------------------------------
      getLocation();
      //--------------------------------------------------- 
      function getLocation()
  {
  if (navigator.geolocation)
    {
  var timeoutVal = 10 * 1000 * 1000;
  navigator.geolocation.getCurrentPosition(initialize,showError,
    {enableHighAccuracy:true,timeout:timeoutVal,maximumAge:0}

  );
        lat = position.coords.latitude; 
        lon = position.coords.longitude;

    }

  }

 //---------------------------------------------------

function initialize() {             
    var myOptions={
    center:latlon,
    zoom:15,
    zoomControl:true,
    zoomControlOptions: {
    style:google.maps.ZoomControlStyle.SMALL
        },
    mapTypeId: google.maps.MapTypeId.ROADMAP
    };          


       map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

              myListener = google.maps.event.addListener(map, 'click', function(event) {
                    placeMarker(event.latLng);
                    google.maps.event.removeListener(myListener);
                    });

              google.maps.event.addListener(map, 'drag', function(event) {
                    placeMarker(event.latLng);
                    google.maps.event.removeListener(myListener);
                    });




        // Try W3C Geolocation (Preferred)
             if(navigator.geolocation) {
               // browserSupportFlag = true;
                navigator.geolocation.getCurrentPosition(function(position) {
          initialLocation = new google.maps.LatLng(position.coords.latitude,position.coords.longitude);
                map.setCenter(initialLocation);
               }, function() {
                showError;
                });
                }

                function placeMarker(location) {

                  marker = new google.maps.Marker({
                        position: location,
            icon:'map_icon3.png',
            animation:google.maps.Animation.DROP,
                        map: map,
                        draggable: true
                    });
        marker.setMap(map);
                    map.setCenter(location);
                    var markerPosition = marker.getPosition();
                    populateInputs(markerPosition);
                    google.maps.event.addListener(marker, "drag", function (mEvent) {
                    populateInputs(mEvent.latLng);
                    });
                }

                function populateInputs(pos) {
                    document.getElementById("t1").value=pos.lat()
                    document.getElementById("t2").value=pos.lng();
                }
            }


//-------------------------------------------------------------------
function showError(error)
  {
  switch(error.code) 
    {
    case error.PERMISSION_DENIED:
      x.innerHTML="User Denied Geolocation"
      break;
    case error.POSITION_UNAVAILABLE:
      x.innerHTML="Location Data Unavailable"
      break;
    case error.TIMEOUT:
      x.innerHTML="Request Timed Out"
      break;
    case error.UNKNOWN_ERROR:
      x.innerHTML="Unknown Error Occurred"
      break;
    }
  }
        </script>
    </head>
    <body onload="initialize()">
        <div id="map_canvas" style="width: 500px; height: 500px"></div>
        <input type="text" id="t1" name="t1" />
        <input type="text" id="t2" name="t2" />
    </body>
</html>

Answer 1

请确保在创建标记时您在图标下提到的图像文件是可访问的，即它的路径是正确的。

我将图标图像更改为以下内容并且标记可见：

marker = new google.maps.Marker({
                    position: location,
                    icon:'http://google.com/mapfiles/ms/micons/red.png',
                    animation:google.maps.Animation.DROP,
                    map: map,
                    draggable: true
                });

我无法通过浏览器获得该位置。它一直给我一个错误说：

position is not defined
lat = position.coords.latitude;

为了避免这种情况，我将初始化函数中的myOptions中的latlon变量更改为以固定点为中心。

var latlng = new google.maps.LatLng(19.16981,72.85434);        
var myOptions={
center:latlng,
zoom:15,
zoomControl:true,
zoomControlOptions: {
style:google.maps.ZoomControlStyle.SMALL
    },
mapTypeId: google.maps.MapTypeId.ROADMAP
};

您为地图拖动事件添加的侦听器会产生错误，因为它不会返回MouseEvent，因此不会获得任何位置。即使省略了这个监听器，代码仍然可以工作。

根据v3文档

https://developers.google.com/maps/documentation/javascript/reference#Map

拖动无在用户拖动地图时重复触发此事件。

希望这会帮助你。如果有效，请告诉我。

初始化地图时，Google地图标记不会显示

1 个答案: