显示数据库中的标记

display the Marker from database

本文关键字：数据库显示更新时间：2023-09-26

以下java script将显示google地图中的标记。在这里我添加了Control按钮以LEFT_BOTTOM 。我的输出显示所有标记。但是当我单击Control按钮时，我需要从数据库中过滤一些标记。我应该怎么做？

 <style type="text/css">
            body { font: normal 10pt Helvetica, Arial; }
            #map { width: 100%; height: 100%; border: 0px; padding: 0px; }
    </style>
    <script src="http://maps.google.com/maps/api/js?v=3&sensor=false" type="text/javascript"></script>
    <script type="text/javascript">
        var icon = new google.maps.MarkerImage("images/icons/icon.png",
                       new google.maps.Size(32, 32), new google.maps.Point(0, 0),
                       new google.maps.Point(16, 32));
        var center = null;
        var map = null;
        var currentPopup;
        var bounds = new google.maps.LatLngBounds();
        //adding multiple marker
        function addMarker(lat, lng, info) {
            var pt = new google.maps.LatLng(lat, lng);
            bounds.extend(pt);
            var marker = new google.maps.Marker({
                position: pt,
                icon: icon,
                map: map});
            var popup = new google.maps.InfoWindow({
                content: info,
                maxWidth: 300 });
            google.maps.event.addListener(marker, "click", function() {
                if (currentPopup != null) {
                    currentPopup.close();
                    currentPopup = null;
                }
                popup.open(map, marker);
                currentPopup = popup;});
            google.maps.event.addListener(popup, "closeclick", function() {
                map.panTo(center);
                currentPopup = null;
            });
        }
        function HomeControl(controlDiv, map) {
          // Set CSS styles for the DIV containing the control
          // Setting padding to 5 px will offset the control
          // from the edge of the map
          controlDiv.style.padding = '5px';
          // Set CSS for the control border
          var controlUI = document.createElement('div');
          controlUI.style.backgroundColor = 'white';
          controlUI.style.borderStyle = 'solid';
          controlUI.style.borderWidth = '2px';
          controlUI.style.cursor = 'pointer';
          controlUI.style.textAlign = 'center';
          controlUI.title = 'Click to Filter';
          controlDiv.appendChild(controlUI);
          // Set CSS for the control interior
          var controlText = document.createElement('div');
          controlText.style.fontFamily = 'Arial,sans-serif';
          controlText.style.fontSize = '12px';
          controlText.style.paddingLeft = '4px';
          controlText.style.paddingRight = '4px';
          controlText.innerHTML = '<b>GYM</b>';
          controlUI.appendChild(controlText);
          // Setup the click event listeners: simply set the map to
          google.maps.event.addDomListener(controlUI, 'click', function() {     
                //need to filter Markers
                //$query = mysql_query("SELECT * FROM mytable where availability = false");

          });
        }
        function initMap() {
            map = new google.maps.Map(document.getElementById("map"), {
                center: new google.maps.LatLng(0, 0),
                zoom: 14,
                mapTypeId: google.maps.MapTypeId.ROADMAP,
                mapTypeControl: false,
                mapTypeControlOptions: {
                    style: google.maps.MapTypeControlStyle.HORIZONTAL_BAR
                },
                navigationControl: true,
                navigationControlOptions: {
                    style: google.maps.NavigationControlStyle.SMALL}});
            <?php
                $query = mysql_query("SELECT * FROM mytable ");
                while ($row = mysql_fetch_array($query)){
                    $regno      =   $row['id'];
                    $latitude   =   $row['latitude'];
                    $longitude  =   $row['longitude'];  
                    echo "addMarker($longitude, $latitude,'<b>$id</b>');";
                }
            ?>
            center = bounds.getCenter();
            map.fitBounds(bounds);
            var homeControlDiv = document.createElement('div');
            var homeControl = new HomeControl(homeControlDiv, map);
            homeControlDiv.index = 1;
            map.controls[google.maps.ControlPosition.LEFT_BOTTOM].push(homeControlDiv);
        }
    </script>
----
<body onLoad="initMap()" style="margin:0px; border:0px; padding:0px;">

创建标记时，将它们推送到数组（推送每个标记对象）。
单击按钮时，循环访问标记数组并调用每个标记上的setMap(null)。
使用筛选器再次查询数据库

这里有一些快速代码，以便你明白：

// Create an array of markers
var markers = [];
// Create your map and all the stuff you need
// Bind the event listener
google.maps.event.addDomListener(controlUI, 'click', function() {
    // First delete all your markers
    deleteMarkers();
    // Query your database again and add each marker as you did in the first place
});
// Function to delete the markers
function deleteMarkers() {
    for (var i = 0; i < markers.length; i++) {
        // Remove each marker from map
        markers[i].setMap(null);
    }
}
function addMarker() {
    // Create each marker object
    var marker = new google.maps.Marker({
        map: map,
        // Your other marker properties here
    });
    // Push new marker to the markers array
    markers.push(marker);
}