标记不会显示在来自XML文件的谷歌地图上

问题描述：

因此，我试图从数据库中查询经纬度/长度的谷歌地图上创建标记，并保存到XML文件。我试图从XML文件中抓取位置并放入新的Google标记中，但无法在地图上显示任何标记。标记不会显示在来自XML文件的谷歌地图上

我的HTML/JavaScript的

//Test for markers 
<!DOCTYPE html> 
<html> 
    <head> 
    <style> 
     #map { 
     width: 1200px; 
     height: 900px; 
     } 
    </style> 
    <script src="https://maps.googleapis.com/maps/api/js"></script> 
    <script> 
    var map; 
     function initialize() { 
     var myLatlng = new google.maps.LatLng(38.0400, -122.7400); 
     var mapOptions = { 
      zoom: 10, 
      center: myLatlng 
     } 
     map = new google.maps.Map(document.getElementById("map"), mapOptions); 
     } 
     loadMarkers(); 
     google.maps.event.addDomListener(window, 'load', initialize); 

    function loadMarkers(){ 
     map.markers = map.markers || [] 
     downloadUrl("schools.xml", function(data) { 
      var xml = data.responseXML; 
      markers = xml.documentElement.getElementsByTagName("school"); 
      for(var i = 0; i < markers.length; i++){ 
       var name = markers[i].getAttribute("name"); 
       var point = new google.maps.LatLng(
       parseFloat(markers[i].getAttribute("lat")), 
       parseFloat(markers[i].getAttribute("long"))); 
       var marker = new google.maps.Marker({ 
        map:map, 
        position: point, 
        title:name 
       }); 
       map.markers.push(marker);    
      } 
     }); 
     } 

    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(null); 
    } 
    </script> 
    </head> 
    <body onload = "initialize()"> 
    <div id="map"></div> 
    </body> 
</html>

XML文件

<?xml version="1.0"?> 
-<Schools> 
<school loc="POINT (-122.549936 37.955014)" lat="37.955014" long="-122.549936" county="Marin" zip="94904" state="CA" city="Kentfield" name2="" name="College of Marin"/> 
<school loc="POINT (-122.564302 37.969594)" lat="37.969594" long="-122.564302" county="Marin" zip="94960" state="CA" city="San Anselmo" name2="" name="San Francisco Theological Seminary"/>  
<school loc="POINT (-122.514654 37.980014)" lat="37.980014" long="-122.514654" county="Marin" zip="94901" state="CA" city="San Rafael" name2="" name="Dominican University of California"/> 
</Schools>

可能是一个计时问题。我会将loadMarkers调用移入初始化函数中以开始。错误控制台说什么？ – lucas

@lucas我将loadMarkers修正为初始化函数，但仍然没有运气。错误控制台告诉我doNothing是未定义的 –

这是因为'doNothing'没有被定义......这是'doNothing'的一个好的定义：'function doNothing（）{}' – geocodezip

答

你的代码有一个JavaScript错误：Uncaught TypeError: Cannot read property 'markers' of undefined在这条线：

map.markers = map.markers || []

要调用前的loadMarkers地图被定义。在初始化例程中调用它。

function initialize() { 
    var myLatlng = new google.maps.LatLng(38.0400, -122.7400); 
    var mapOptions = { 
    zoom: 10, 
    center: myLatlng 
    } 
    map = new google.maps.Map(document.getElementById("map"), mapOptions); 
    loadMarkers(); 
}

标记不会显示在来自XML文件的谷歌地图上

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