Google 地图在点击时根本不显示标记的描述 properly/not

Question

在这个地方的两个 for 循环（tempus 循环和 research_academic 循环）中都无法读取属性 'marker' of null：

       ra.marker.infowin.open(map,ra.marker);

我试图修复它，但我没有主意。

<div id="map_canvas" style="width: 100%; height: 600px;"></div>
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?sensor=false"></script><script type="text/javascript">// <![CDATA[
<!--
var research_academic_icon = 'http://aib.etf.unsa.ba/wp-content/uploads/2014/04/marker_green.png';
var home_icon = 'http://aib.etf.unsa.ba/wp-content/uploads/2014/04/aib.png';
var tempus_icon = 'http://aib.etf.unsa.ba/wp-content/uploads/2014/06/marker_red.png';
var styles = [{name:'AIB - ETF Sarajevo', icon:home_icon},
              {name:'Research and Academic cooperation', icon:research_academic_icon},
              {name:'Tempus Projects', icon:tempus_icon}
];
var research_academic = [
{lat:48.782053, lon:9.174209, name:'University of Stuttgart, Germany', year:'1995', title: 'Research project <b>Anwendung der Technologie der kunstlichen Intelligenz be idem Interface vom verteilten Prozessessteuerungsystem</b>', support:'DAAD support'},
{lat:35.30757, lon:-80.728552, name:'University of North Caroline Charlotte, U.S.A.', year:'2001-2002', title: 'Research project <b>Intelligent Control and Evolutionary Computation</b>', support:'FULBRIGHT support'},
{lat:49.59788, lon:11.00455, name:'University Friedrich Alexander Erlangen - Nurnberg, Germany', year:'2000-2006', title: 'Research projects <b>Rechnergestuetzter Reglerentwurf fuer ein komplexes Servosystems-Roboterarm Intelligente Verfahren zur Regelung von Fahrzeugen und Fahrzeugkomponenten', support:'DAAD support'},
{lat:51.706768, lon:8.771104, name:'University of Paderborn, Germany', year:'2006-2007', title: 'Research project  <b>Intelligent Agent Framework  for Software Applications Development</b>', support:'DAAD support'},
{lat:51.453981, lon:-2.592980, name: 'University of Bristol, UK', year:'2004-2005', title: 'Research project  <b>Virtual 3D Reconstruction of Heritage Sites of Bosnia and Herzegovina</b>', support:'UNESCO support'},
{lat:59.6186 , lon:16.540657, name: ' University of Malerdalen, Sweden', year:'2009-2010', title: 'Research project  <b>Applications of Artificial Intelligence in Areas of Control Engineering</b>', support:'Joint Linnaeus-Palme support'},
{lat:46.049194, lon:14.504155, name: 'University of Ljubljana, Slovenia', year:'2014-2015', title: ' Bilateral research project <b>Computer Based Modeling in Bioinformatics for Gene Based Cancer Classification Focused on Reliability and Machine Learning</b>', support:'FMON-Bosnia and Herzegovina'},
{lat:-27.565999, lon:153.070216, name: 'University of Griffit, Australia', year:'2011-', title: 'Open collaboration <b>Bioinformatics</b>', support:'University Griffit academic support'},
{lat:37.723358,lon:-122.482540, name: 'University of California, San Francisco, U.S.A.', year:'2009-', title: 'Open collaboration<b> Biomedical Systems and  Clinical Pharmacy </b>', support: 'Peer-to-peer support scheme'},
{lat:41.99942, lon:21.443239, name: ' St. Cyril and Methodius University, Macedonia', year:'2008', title: 'Short term academic collaboration', support:'St.Cyril and Methodius University'},
{lat:43.821747, lon:18.309177, name: 'International University of Sarajevo, Bosnia and Herzegovina', year:'2013', title: 'Short term academic collaboration', support:'None'},
{lat: 44.538822, lon: 18.664618, name: ' University of Tuzla, Bosnia and Herzegovina', year:'1997-2005', title: ' Research and educational   colaboration <b>Real Time Intelligent Systems</b>', support:' University Tuzla academic support scheme'},
{lat: 43.354766, lon: 17.809364, name: ' University Džemal Bijedić of Mostar, Bosnia and Herzegovina', year:'2008', title: ' Short term  collaboration  <b>Geoinformatics</b>', support:' University Mostar academic support scheme'},
{lat: 47.177288, lon: 7.414258, name: ' University of Bern, Switzerland', year:'2013-2016', title: '<b>Decision Support System for Leukemia Cancer Diagnosis, Survival Prognosis, Treatment Monitoring, and Biomarkers Discovery Using Fusion of Artificial Intelligence Methods and Gene Microarray Technologies in the Area of Personalized Medicine</b>', support:' SCOPES 2013-2016: Joint Research Projects Review of expert team: POSITIVE; No financial support'},
];
var tempus = [
{lat: 51.707169, lon: 8.782150, name: ' University of Paderborn, Germany; University of Lleida, Spain', year:'2002-2005', title: '<b>Curriculum Development for Computer Science Studies in BiH</b>', support:' Tempus JEP-UM-16110-2001'},
{lat: 41.618342, lon: 0.619934, name: ' University of Paderborn, Germany; University of Lleida, Spain', year:'2002-2005', title: '<b>Curriculum Development for Computer Science Studies in BiH</b>', support:' Tempus JEP-UM-16110-2001'},
{lat: 41.615262, lon: 0.621823, name: ' University of Paderborn, Germany; University of Lleida, Spain', year:'2005-2008', title: '<b>Quality Assurance of High Education through Accreditation</b>', support:' Tempus JEP-UM-19015-2004'},
{lat: 51.707488, lon: 8.760693, name: ' University of Paderborn, Germany; University of Lleida, Spain', year:'2005-2008', title: '<b>Quality Assurance of High Education through Accreditation</b>', support:' Tempus JEP-UM-19015-2004'},
{lat: 51.321787, lon: 9.506447, name: ' University of Paderborn, Germany; University of Lleida, Spain; University Kassel, Germany', year:'2007-2008', title: '<b>IT Qualifications Framework for HE in BiH</b>', support:' Tempus SCM-C010B06-2006 (BA)'},
{lat: 41.617316, lon: 0.629033, name: ' University of Paderborn, Germany; University of Lleida, Spain; University Kassel, Germany', year:'2007-2008', title: '<b>IT Qualifications Framework for HE in BiH</b>', support:' Tempus SCM-C010B06-2006 (BA)'},
{lat: 51.713409, lon: 8.780542, name: ' University of Paderborn, Germany; University of Lleida, Spain; University Kassel, Germany', year:'2007-2008', title: '<b>IT Qualifications Framework for HE in BiH</b>', support:' Tempus SCM-C010B06-2006 (BA)'},
{lat: 51.061017, lon: 3.708398, name: ' KAHO Sint Lieven (Gent), Belgium; Porto Plotechnic Institute, Portugal; University Brasov, Romania', year:'2009-2012', title: '<b>European Union standards for accreditation of study programs on BH Universities (ESABIH)</b>', support:' Tempus SMGR 158853-1-2009-1-SE'},
{lat: 41.179675, lon: -8.599422, name: ' KAHO Sint Lieven (Gent), Belgium; Porto Plotechnic Institute, Portugal; University Brasov, Romania', year:'2009-2012', title: '<b>European Union standards for accreditation of study programs on BH Universities (ESABIH)</b>', support:' Tempus SMGR 158853-1-2009-1-SE'},
{lat: 45.660203, lon: 25.605498, name: ' KAHO Sint Lieven (Gent), Belgium; Porto Plotechnic Institute, Portugal; University Brasov, Romania', year:'2009-2012', title: '<b>European Union standards for accreditation of study programs on BH Universities (ESABIH)</b>', support:' Tempus SMGR 158853-1-2009-1-SE'},
];
function round2six(num){
     return Math.round(num * 1000000) / 1000000;
}
function get_mark_by_geo(lat, lon){
   lat = round2six(lat);
   lon = round2six(lon);
   for(var i=0; i<research_academic.length; i++){
      if(research_academic[i].lat == lat)
         if(research_academic[i].lon == lon)
            return research_academic[i];
   }
   return null;
}
function get_tempus_mark_by_geo(lat, lon){
   lat = round2six(lat);
   lon = round2six(lon);
   for(var i=0; i<tempus.length; i++){
      if(tempus[i].lat == lat)
         if(tempus[i].lon == lon)
            return tempus[i];
   }
   return null;
}
function initialize() {
    var mapCanvas = document.getElementById('map_canvas');
    var mapOptions = {
      center: new google.maps.LatLng(42.094728, -39.758346),
      zoom: 3,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    }
    var map = new google.maps.Map(mapCanvas, mapOptions);
    map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push(document.getElementById('legend'));    
    var marker = new google.maps.Marker({
      position: new google.maps.LatLng(43.856705, 18.398419),
      map: map,
      icon: home_icon,
      content: 'AIB at etf.unsa.ba'
    });
    google.maps.event.addListener(marker, 'click', function() {    
        var infowindow = new google.maps.InfoWindow({content: marker.content});
        infowindow.open(map,marker);
    });
    for(var i=0; i<research_academic.length; i++){
       var c = research_academic[i].name+"<br/>"+research_academic[i].title+"<br/><br/>"+research_academic[i].year+" - "+research_academic[i].support;
       research_academic[i].marker = new google.maps.Marker({
         position: new google.maps.LatLng(research_academic[i].lat, research_academic[i].lon),
         map: map,
         icon: research_academic_icon,
         infowin: new google.maps.InfoWindow({content: c})
       });
       google.maps.event.addListener(research_academic[i].marker, 'click', function(event) {
            var ra = get_mark_by_geo(event.latLng.k, event.latLng.B);
            ra.marker.infowin.open(map,ra.marker);
       });
    }
    for(var i=0; i<tempus.length; i++){
       var c = tempus[i].name+"<br/>"+tempus[i].title+"<br/><br/>"+tempus[i].year+" - "+tempus[i].support;
       tempus[i].marker = new google.maps.Marker({
         position: new google.maps.LatLng(tempus[i].lat, tempus[i].lon),
         map: map,
         icon: tempus_icon,
         infowin: new google.maps.InfoWindow({content: c})
       });
       google.maps.event.addListener(tempus[i].marker, 'click', function(event) {
            var ra = get_tempus_mark_by_geo(event.latLng.k, event.latLng.B);
            ra.marker.infowin.open(map,ra.marker);
       });
    }
    // add legend
    var legend = document.getElementById('legend');
    for (var i = 0; i < styles.length; i++) {
      var div = document.createElement('div');
      div.innerHTML = '<img src="' + styles[i].icon + '"> ' + styles[i].name;
      legend.appendChild(div);
    }
  }
  google.maps.event.addDomListener(window, 'load', initialize);
// ]]></script>

Answer 1

更改以下内容：

var ra = get_mark_by_geo(event.latLng.k, event.latLng.B);

至

var ra = get_mark_by_geo(event.latLng.A, event.latLng.F);

Google 地图在点击时根本不显示标记的描述 properly/not

Google map doesn't display marker's description properly/not at all on click

javascript

wordpress

google-maps

google-maps-api-3

jsfiddle