谷歌地图标记不被替换

Question

请原谅在这个小菜。当用户点击地图时，它应该放置一个标记并打开一个信息窗口 - 根据这个示例：http://www.geocodezip.com/v3_example_click2add_infowindow.html 下面的代码几乎可以正常工作，除了标记未被替换 - 添加了一个新标记。任何想法真的，真的感激地收到。谢谢。

<script> 
    var map = null; 
    var markersArray = []; 

    function initialize() { 
     var latlng = new google.maps.LatLng(0.0000, 0.0000); 

     var settings = { 
      zoom: 2, 
      mapTypeControl:true, 
      center: latlng, 
      panControl:true, 
      zoomControl:true, 
      streetViewControl:false, 
      overviewMapControl:false, 
      rotateControl:true, 
      scaleControl: true, 
      navigationControl: true, 
      navigationControlOptions: { 
       style: google.maps.NavigationControlStyle.DEFAULT 
      }, 
      mapTypeId: google.maps.MapTypeId.ROADMAP, 
      backgroundColor: 'white' 
     }; 

     map = new google.maps.Map(document.getElementById('map'), settings); 

     function placeMarker(location) { 
     var marker , i ; 
     if (marker) { 
       marker.setPosition(location); 
      } else { 
       marker = new google.maps.Marker({ 
      position: location, 
      icon:'http://www.desperatesailors.com/templates/Live/media/mapicons/info.png', 
      map: map 
      }); 
      var infowindow = new google.maps.InfoWindow({ 
       content: 'Latitude: ' + location.lat() + 
        '<br>Longitude: ' + location.lng() + 
        '<br>Only the first four decimal places needed' 
      }); 
      infowindow.open(map,marker); 
      } 
     } 

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

    window.onload = initialize; 
</script> 

Answer 1

您的placeMarker函数在本地作用域中创建一个新的（空）标记变量。

function placeMarker(location) { 
    var marker , i ; 
    if (marker) { 

它总是会创建一个新的标记。将其更改为：

var marker = null; 
function placeMarker(location) { 
    if (marker) { 

Answer 2

这是范围问题。您总是在placeMarker函数中删除标记，所以如果（标记）将始终为假。将变量声明移出该函数：

<script> 
    var marker; 
    var map = null; 
    var markersArray = []; 

    function initialize() { 
     var latlng = new google.maps.LatLng(0.0000, 0.0000); 

     var settings = { 
      zoom: 2, 
      mapTypeControl:true, 
      center: latlng, 
      panControl:true, 
      zoomControl:true, 
      streetViewControl:false, 
      overviewMapControl:false, 
      rotateControl:true, 
      scaleControl: true, 
      navigationControl: true, 
      navigationControlOptions: { 
       style: google.maps.NavigationControlStyle.DEFAULT 
      }, 
      mapTypeId: google.maps.MapTypeId.ROADMAP, 
      backgroundColor: 'white' 
     }; 

     map = new google.maps.Map(document.getElementById('map'), settings); 

     function placeMarker(location) { 
     var i ; 
     if (marker) { 
       marker.setPosition(location); 
      } else { 
       marker = new google.maps.Marker({ 
      position: location, 
      icon:'http://www.desperatesailors.com/templates/Live/media/mapicons/info.png', 
      map: map 
      }); 
      var infowindow = new google.maps.InfoWindow({ 
       content: 'Latitude: ' + location.lat() + 
        '<br>Longitude: ' + location.lng() + 
        '<br>Only the first four decimal places needed' 
      }); 
      infowindow.open(map,marker); 
      } 
     } 

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

    window.onload = initialize; 
</script>