Javascript 实时更新标记，无需加载Google Maps API V3页面_Javascript_Html_Css_Google Maps_Google Maps Api 3

Javascript 实时更新标记，无需加载Google Maps API V3页面

javascript html css google-maps google-maps-api-3

Javascript 实时更新标记，无需加载Google Maps API V3页面,javascript,html,css,google-maps,google-maps-api-3,Javascript,Html,Css,Google Maps,Google Maps Api 3,Im使用Google Maps API V3标记php/sql。我的问题是，我希望根据存储在sql db中的数据实时更新标记，因为我需要它来为我的capstone项目提供应急响应系统。但是我看到有2到3个线程有同样的问题，但是当我尝试使用这些代码时，什么都没有发生。请有人告诉我该怎么办。我已经连续一天这么做了，但什么都没发生我想要达到的是这是我的密码 <!DOCTYPE html > <head> <meta name="viewport" con

Im使用Google Maps API V3标记php/sql。我的问题是，我希望根据存储在sql db中的数据实时更新标记，因为我需要它来为我的capstone项目提供应急响应系统。但是我看到有2到3个线程有同样的问题，但是当我尝试使用这些代码时，什么都没有发生。请有人告诉我该怎么办。我已经连续一天这么做了，但什么都没发生

我想要达到的是

这是我的密码

<!DOCTYPE html >
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
  <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <title>PHP/MySQL & Google Maps Example</title>
    <script type="text/javascript" src="https://maps.googleapis.com/maps/api/js"></script>
    <script type="text/javascript">
    //<![CDATA[

    var customIcons = {
      restaurant: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_blue.png'
      },
      bar: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_red.png'
      }
    };

    function load() {
      var map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
      });
      var infoWindow = new google.maps.InfoWindow;
      // Change this depending on the name of your PHP fil
     downloadUrl("poy.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 type = markers[i].getAttribute("type");
          var point = new google.maps.LatLng(
              parseFloat(markers[i].getAttribute("lat")),
              parseFloat(markers[i].getAttribute("lng")));
          var html = "<b>" + name + "</b> <br/>" + address + "<br/>" + point;
          var icon = customIcons[type] || {};
          var marker = new google.maps.Marker({
            map: map,
            position: point,
            icon: icon.icon
          });
          bindInfoWindow(marker, map, infoWindow, html);
        }
      });
    }   

    function bindInfoWindow(marker, map, infoWindow, html) {
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, 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);
    }

    function doNothing() {}


    //]]>

  </script>

  </head>

  <body onload="load()">
  <div id="map" style="width: 700px; height: 500px"></div>
  </body>

</html>


PHP/MySQL和googlemaps示例
//

这是未经测试的，但您应该了解这一点。在

load（）

函数中，设置触发下载的时间间隔

var map, infoWindow, intervalId;

var customIcons = {
    restaurant: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_blue.png'
    },
    bar: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_red.png'
    }
};

function load() {
    map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
    });

    infoWindow = new google.maps.InfoWindow;

    // Trigger downloadUrl at an interval
    intervalId = setInterval(triggerDownload, 5000);
}

function bindInfoWindow(marker, map, infoWindow, html) {
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
    });
}

function triggerDownload() {
    // Change this depending on the name of your PHP file
    downloadUrl("poy.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 type = markers[i].getAttribute("type");
            var point = new google.maps.LatLng(
            parseFloat(markers[i].getAttribute("lat")),
            parseFloat(markers[i].getAttribute("lng")));
            var html = "<b>" + name + "</b> <br/>" + address + "<br/>" + point;
            var icon = customIcons[type] || {};
            var marker = new google.maps.Marker({
                map: map,
                position: point,
                icon: icon.icon
            });
            bindInfoWindow(marker, map, infoWindow, html);
        }
    });
}

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);
}

function doNothing() {}

警告：您正在使用异步的

XMLHttpRequest

。这意味着您可以在完成上一个请求之前调用

downloadUrl

，这可能会导致不必要的行为。

此代码对我非常有用：

    <script type="text/javascript">
    //<![CDATA[

   var map, infoWindow, intervalId;

var customIcons = {
    restaurant: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_blue.png'
    },
    bar: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_red.png'
    }
};

function load() {
    map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
    });

    infoWindow = new google.maps.InfoWindow;

    // Trigger downloadUrl at an interval
    intervalId = setInterval(triggerDownload, 1000);
}

function bindInfoWindow(marker, map, infoWindow, html) {
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
    });
}

function bindInfoWindow(marker, map, infoWindow, html) {
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
    });
}

var markersArray = [];

function clearOverlays() {
  for (var i = 0; i < markersArray.length; i++ ) {
   markersArray[i].setMap(null);
  }
}

function triggerDownload() {
    clearOverlays();
    // Change this depending on the name of your PHP file
    downloadUrl("poy.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 type = markers[i].getAttribute("type");
            var point = new google.maps.LatLng(
            parseFloat(markers[i].getAttribute("lat")),
            parseFloat(markers[i].getAttribute("lng")));
            var html = "<b>" + name + "</b> <br/>" + address + "<br/>" + point;
            var icon = customIcons[type] || {};
            var marker = new google.maps.Marker({
                map: map,
                position: point,
                icon: icon.icon
            });
            markersArray.push(marker);
            bindInfoWindow(marker, map, infoWindow, html);
        }
    });
}

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);
}

function doNothing() {}

    //]]>

  </script>

//

您在第一次加载时看到您的标记了吗？您只调用了一次

downloadUrl

，因此它不会刷新。看看是否要重复调用该函数。是的，我看到了。但是我应该把代码setInterval放在哪里呢？。在函数downloadUrl上或函数load？内？。请帮助我，先生。先生，请编辑我上面的代码，并在这里发布正确的setInterval代码。谢谢，先生，非常感谢。我很感激这个答案，但我很抱歉没有这样说，我已经做了这种代码。这段代码的问题是。如果我刷新我的页面，我将等待5秒钟加载标记，然后如果加载了标记，setinterval将停止并不再循环。这是我的完整文件，请尝试一下。看看问题所在。

    <script type="text/javascript">
    //<![CDATA[

   var map, infoWindow, intervalId;

var customIcons = {
    restaurant: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_blue.png'
    },
    bar: {
        icon: 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_red.png'
    }
};

function load() {
    map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
    });

    infoWindow = new google.maps.InfoWindow;

    // Trigger downloadUrl at an interval
    intervalId = setInterval(triggerDownload, 1000);
}

function bindInfoWindow(marker, map, infoWindow, html) {
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
    });
}

function bindInfoWindow(marker, map, infoWindow, html) {
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
    });
}

var markersArray = [];

function clearOverlays() {
  for (var i = 0; i < markersArray.length; i++ ) {
   markersArray[i].setMap(null);
  }
}

function triggerDownload() {
    clearOverlays();
    // Change this depending on the name of your PHP file
    downloadUrl("poy.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 type = markers[i].getAttribute("type");
            var point = new google.maps.LatLng(
            parseFloat(markers[i].getAttribute("lat")),
            parseFloat(markers[i].getAttribute("lng")));
            var html = "<b>" + name + "</b> <br/>" + address + "<br/>" + point;
            var icon = customIcons[type] || {};
            var marker = new google.maps.Marker({
                map: map,
                position: point,
                icon: icon.icon
            });
            markersArray.push(marker);
            bindInfoWindow(marker, map, infoWindow, html);
        }
    });
}

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);
}

function doNothing() {}

    //]]>

  </script>