谷歌地图，PHP答案

【问题标题】：Google maps, PHP谷歌地图，PHP
【发布时间】：2012-03-04 11:13:34
【问题描述】：

我对 php 还很陌生，还没有弄清楚如何执行某项任务。

我的代码让用户输入他们的地址，然后选择半径搜索，在他们搜索后生成一张地图，显示最近的 3 个位置到他们的地址。

我想这样当用户从 map 它为单击的项目生成一个页面。说你点击了 “商店名称”。你能帮我理解这是怎么回事吗完毕？谢谢。

      <?php

    require("phpsqlsearch_dbinfo.php");

    // Get parameters from URL
    $center_lat = $_GET["lat"];
    $center_lng = $_GET["lng"];
    $radius = $_GET["radius"];

    // Start XML file, create parent node
    $dom = new DOMDocument("1.0");
    $node = $dom->createElement("markers");
    $parnode = $dom->appendChild($node);

    // Opens a connection to a mySQL server
    $connection=mysql_connect ('localhost', $username, $password);
    if (!$connection) {
      die("Not connected : " . mysql_error());
    }

    // Set the active mySQL database
    $db_selected = mysql_select_db($database, $connection);
    if (!$db_selected) {
      die ("Can\'t use db : " . mysql_error());
    }

    // Search the rows in the markers table
    $query = sprintf("SELECT address, name, lat, lng, ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance FROM markers HAVING distance < '%s' ORDER BY distance LIMIT 0 , 3",
      mysql_real_escape_string($center_lat),
      mysql_real_escape_string($center_lng),
      mysql_real_escape_string($center_lat),
      mysql_real_escape_string($radius));
    $result = mysql_query($query);

    if (!$result) {
      die("Invalid query: " . mysql_error());
    }

    header("Content-type: text/xml");

    // Iterate through the rows, adding XML nodes for each
    while ($row = @mysql_fetch_assoc($result)){
      $node = $dom->createElement("marker");
      $newnode = $parnode->appendChild($node);
      $newnode->setAttribute("name", $row['name']);
      $newnode->setAttribute("address", $row['address']);
      $newnode->setAttribute("lat", $row['lat']);
      $newnode->setAttribute("lng", $row['lng']);
      $newnode->setAttribute("distance", $row['distance']);
    }

    echo $dom->saveXML();
?>

和

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <title>Google Maps AJAX + mySQL/PHP Example</title>
    <script src="http://maps.google.com/maps/api/js?sensor=false"
            type="text/javascript"></script>
    <script type="text/javascript">
    //<![CDATA[
    var map;
    var markers = [];
    var infoWindow;
    var locationSelect;

    function load() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(40, -100),
        zoom: 4,
        mapTypeId: 'roadmap',
        mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU}
      });
      infoWindow = new google.maps.InfoWindow();

      locationSelect = document.getElementById("locationSelect");
      locationSelect.onchange = function() {
        var markerNum = locationSelect.options[locationSelect.selectedIndex].value;
        if (markerNum != "none"){
          google.maps.event.trigger(markers[markerNum], 'click');
        }
      };
   }

   function searchLocations() {
     var address = document.getElementById("addressInput").value;
     var geocoder = new google.maps.Geocoder();
     geocoder.geocode({address: address}, function(results, status) {
       if (status == google.maps.GeocoderStatus.OK) {
        searchLocationsNear(results[0].geometry.location);
       } else {
         alert(address + ' not found');
       }
     });
   }

   function clearLocations() {
     infoWindow.close();
     for (var i = 0; i < markers.length; i++) {
       markers[i].setMap(null);
     }
     markers.length = 0;

     locationSelect.innerHTML = "";
     var option = document.createElement("option");
     option.value = "none";
     option.innerHTML = "See all results:";
     locationSelect.appendChild(option);
   }

   function searchLocationsNear(center) {
     clearLocations(); 

     var radius = document.getElementById('radiusSelect').value;
     var searchUrl = 'phpsqlsearch_genxml.php?lat=' + center.lat() + '&lng=' + center.lng() + '&radius=' + radius;
     downloadUrl(searchUrl, function(data) {
       var xml = parseXml(data);
       var markerNodes = xml.documentElement.getElementsByTagName("marker");
       var bounds = new google.maps.LatLngBounds();
       for (var i = 0; i < markerNodes.length; i++) {
         var name = markerNodes[i].getAttribute("name");
         var address = markerNodes[i].getAttribute("address");
         var distance = parseFloat(markerNodes[i].getAttribute("distance"));
         var latlng = new google.maps.LatLng(
              parseFloat(markerNodes[i].getAttribute("lat")),
              parseFloat(markerNodes[i].getAttribute("lng")));

         createOption(name, distance, i);
         createMarker(latlng, name, address);
         bounds.extend(latlng);
       }
       map.fitBounds(bounds);
       locationSelect.style.visibility = "visible";
       locationSelect.onchange = function() {
         var markerNum = locationSelect.options[locationSelect.selectedIndex].value;
         google.maps.event.trigger(markers[markerNum], 'click');
       };
      });
    }

    function createMarker(latlng, name, address) {
      var html = "<b>" + name + "</b> <br/>" + address;
      var marker = new google.maps.Marker({
        map: map,
        position: latlng
      });
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
      });
      markers.push(marker);
    }

    function createOption(name, distance, num) {
      var option = document.createElement("option");
      option.value = num;
      option.innerHTML = name + "(" + distance.toFixed(1) + ")";
      locationSelect.appendChild(option);
    }

    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.responseText, request.status);
        }
      };

      request.open('GET', url, true);
      request.send(null);
    }

    function parseXml(str) {
      if (window.ActiveXObject) {
        var doc = new ActiveXObject('Microsoft.XMLDOM');
        doc.loadXML(str);
        return doc;
      } else if (window.DOMParser) {
        return (new DOMParser).parseFromString(str, 'text/xml');
      }
    }

    function doNothing() {}

    //]]>
  </script>
  </head>

  <body style="margin:0px; padding:0px;" onload="load()"> 
    <div>
     <input type="text" id="addressInput" size="10"/>
    <select id="radiusSelect">
      <option value="3" selected>3mi</option>
      <option value="5">5mi</option>
      <option value="10">10mi</option>
      <option value="25">25mi</option>
    </select>

    <input type="button" onclick="searchLocations();" value="Search"/>

    </div>
    <div><select id="locationSelect" style="width:500;visibility:hidden"></select></div>
    <div id="map" style="width: 500; height: 500"></div>
  </body>
</html>

【问题讨论】：

“它会为点击的项目生成一个页面”是什么意思？你想在后台异步生成一个页面还是只打开一个带有新 url 的页面？

标签： php mysql google-maps-api-3

【解决方案1】：

在 JS 中存在一个全局变量位置。通过更改 href 属性，您可以强制浏览器打开另一个 url。文档：http://www.w3schools.com/jsref/obj_location.asp

如果您需要有关单击标记的信息，您可以将此信息放在一个闭包范围内，以便稍后在单击标记时重用它。 create-function 在运行时调用，返回的匿名函数由 click 事件调用。

伪代码：

function createCLickCallback(marker) {
    return function () {
        var position = marker.getPosition();
        location.href = "locationInfo.php?lat=" + position.lat() + "&lng=" + position.lng();
    };
}

google.maps.event.addListener(marker, 'click', createCLickCallback(marker));

【讨论】：

【解决方案2】：

在您的 JS 函数“createMarker”中，您将侦听器添加到标记单击事件： google.maps.event.addListener（标记，“点击”，函数（）{ ... }); 您应该在事件回调函数中添加“页面生成”代码（无论是打开新页面还是更新当前页面的某些部分）。在您当前的代码中，谷歌信息窗口将在您的标记上打开。

【讨论】：