将PHP变量传递给Google Maps API

问题描述：

When a user signs up to my application (college project), they are asked for their address. I convert this address to latitude and longitude and then store it in my database.

I access the latitude and longitude like so:

<?php
    require '../connect.php';
    session_start();
    $_SESSION['username'];

    $sql = "SELECT latitude, longitude FROM userinformation WHERE username = '". $_SESSION['username']. "'";
$result = $db->query($sql);

    if($result->num_rows > 0){
        while($row = $result->fetch_assoc()){
            $lat = $row["latitude"];
            $lng = $row["longitude"];
            echo $lat;
            echo $lng;

        }
    }
?>

I then try to pass the $lat and $lng variable into the Maps API script like so:

function initMap() {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 13,
    center: {lat: '<?php echo $lat;?>', lng: '<?php echo $lng;?>'}
  });

  marker = new google.maps.Marker({
    map: map,
    draggable: true,
    animation: google.maps.Animation.DROP,
    position: {lat: '<?php echo $lat;?>', lng: '<?php echo $lng;?>'}
  });
  marker.addListener('click', toggleBounce);
}

This gives me the following page:

PHP Page

I have also tried converted the PHP variables to JS:

var js_variable  = '<?php echo $lat;?>';
document.write(js_variable);
var js_variable1  = '<?php echo $lng;?>';
document.write(js_variable1);

I then pass in the JS variables instead of the PHP variables, however the output is still the same. What would be the correct way to pass a variable as lat/lng instead of a hardcoded value:

center: {lat: 59.325, lng: 18.070}
position: {lat: 59.327, lng: 18.067}

当用户注册我的应用程序（大学项目）时，会询问他们的地址。我将此地址转换为纬度和经度，然后将其存储在我的数据库中。 p>

我像这样访问纬度和经度： p>

 ＆lt;？php 
 require'../connect.php';  
 session_start（）; 
 $ _SESSION ['username']; 
 
 $ sql =“SELECT纬度，经度FROM userinformation WHERE username ='”。  $ _SESSION [ '用户名'。  “'”; 
 $ result = $ db-＆gt; query（$ sql）; 
 
 if if（$ result-＆gt; num_rows＆gt; 0）{
 while（$ row = $ result-＆gt; fetch_assoc  （））{
 $ lat = $ row [“latitude”]; 
 $ lng = $ row [“longitude”]; 
 echo $ lat; 
 echo $ lng; 
 
} 
}  
？＆gt; 
  code>  pre> 
 
 然后我尝试将$ lat和$ lng变量传递到Maps API脚本中，如下所示： p> 
 
  
  function initMap（）{
 var map = new google.maps.Map（document.getElementById（'map'），{
 zoom：13，
 center：{lat：'＆lt;？  php echo $ lat;？＆gt;'，lng：'＆lt;？php echo $ lng;？＆gt;'} 
}）; 
 
 marker = new google.maps.Marker（{
 map：map  ，
 draggable：true，
 animation：google.maps.Animation.DROP，
 position：{lat：'＆lt;？php echo $ lat;？＆gt;'，lng：'＆lt;？php echo $ lng  ;？＆gt;'} 
}）; 
 marker.addListener（'click'，toggleBounce）; 
} 
  code>  pre> 
 
 这给了我以下页面 ： p> 
 
 
  p> 
 
 
我也有三 ed将PHP变量转换为JS： p> 
 
 
  var js_variable ='＆lt;？php echo $ lat;？＆gt;'; 
document.write（js_variable）; 
var js_variable1  ='＆lt;？php echo $ lng;？＆gt;'; 
document.write（js_variable1）; 
  code>  pre> 
 
 然后传入JS变量而不是 PHP变量，但输出仍然相同。 将变量作为lat / lng而不是硬编码值传递的正确方法是什么： p> 
 
 
  center：{lat：59.325，lng：18.070} 
position：{lat  ：59.327，lng：18.067} 
  code>  pre> 
  div>

答

When I replace the values in the fiddle with strings {lat: '30.365273', lng: '-81.699600'}, I get a javascript error reported by the API: Assertion failed: InvalidValueError: setPosition: not a LatLng or LatLngLiteral: in property lat: not a number.

If I use parseFloat on those strings, it works:

code snippet:

function initMap() {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 13,
    center: {
      lat: parseFloat('30.365273'),
      lng: parseFloat('-81.699600')
    }
  });

  marker = new google.maps.Marker({
    map: map,
    draggable: true,
    animation: google.maps.Animation.DROP,
    position: {
      lat: parseFloat('30.365273'),
      lng: parseFloat('-81.699600')
    }
  });
  marker.addListener('click', toggleBounce);
}
google.maps.event.addDomListener(window, "load", initMap);

html,
body,
#map {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="map"></div>

change your PHP to be:

function initMap() {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 13,
    center: {lat: parseFloat('<?php echo $lat;?>'), lng: parseFloat('<?php echo $lng;?>')}
  });

  marker = new google.maps.Marker({
    map: map,
    draggable: true,
    animation: google.maps.Animation.DROP,
    position: {lat: parseFloat('<?php echo $lat;?>'), lng: parseFloat('<?php echo $lng;?>')}
  });
  marker.addListener('click', toggleBounce);
}

</div>

答

I think having the PHP echo the value directly into your JavaScript is likely the problem. Try passing lat and lng as parameters to your map function instead.

function initMap(myLat, myLng) {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 13,
    center: new google.maps.LatLng(myLat, myLong)
  });

  marker = new google.maps.Marker({
    map: map,
    draggable: true,
    animation: google.maps.Animation.DROP,
    position: new google.maps.LatLng(myLat, myLong)
  });
  marker.addListener('click', toggleBounce);
}

Edit: try using the Google Maps function for setting latitude and longitude, as above.

将PHP变量传递给Google Maps API

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