Question

我有一个带gps点的sql数据库，我想在google maps api上将它们设置为标记。在初始化sql连接之后，我启动了一个while循环，其中我先实现一个php脚本，然后是javascript。但由于某种原因它不起作用。我不知道我犯了什么错误？代码如下所示：

......stuff before
   <?php
    $i=1;
    while($i <48):
    ?>
<!-- SELECT GPS DATA FROM SQL DATABASE AND CONVERT INTO DECIMALS ------------------->
   <?php 
   //select 4 numbers (longitude, altitude) from database

   $result = mysql_query("SELECT kglat, kmlat, kglon, kmlon FROM falpeg WHERE indix='$i'");
   ....
   ....
   .... (converting into decimals for google maps, used mysql_fetch_row, this part should be alright)
   ...
   $klat = ($kmlat / 60) + $kglat;
   round ($kord, 5);
   $klon = ($kmlon / 60) + $kglon;
   ?>

<!-- START JAVASCRIPT --------------------------------------->
   <script type="text/javascript"> 
   var "<?php echo $i; ?>" = {lat: "<?php echo $klat; ?>", lng: "<?php echo $klon; ?>";
   var marker=new google.maps.Marker({
   position: "<?php echo $i; ?>",
   icon:'cross.png'
   });

   marker.setMap(map);
   var infowindow = new google.maps.InfoWindow({
    content:"Hello World!"
   });

   marker.addListener('click', function() {
   infowindow.open(map, marker);
    });
   </script> 

<!-- END WHILE LOOP, SET I++ ------------------->
   <?php
   $i++;
   endwhile;
   ?>

Answer 1

让我们看看我们是否可以清理一下。

•使用PDO（很多好处，但我们只是说它更容易一点）
•构建一个查询，获取所需的所有数据，而不是循环运行单个查询 •尽量不要在整个地方回应PHP ..！
•当你说echo $ i时，我看到你要做什么，但是，$ i只是一个整数值，所以你需要先将数据存储到数组中，然后使用$ myArray [$ i]; <登记/> •利用json_encode获取所需格式的信息

PHP：

<?php

// connect to the DB using PDO
$db = new PDO('mysql:host=host;dbname=dbname','username','password');

// Create a SQL statement that will return ALL of the rows you need
$min = 0;
$max = 47;
$sql = "SELECT kglat, kmlat, kglon, kmlon FROM falpeg WHERE indix BETWEEN $min AND $max;");

$query = $db->query($sql);  // run the query
$results = $query->fetchall(); // fetch the results

// these results are in an array..!  You can access each item
// $results[index]['columnname'] index is just an integer starting a 0
//     ex.  $results[0]['kglat'] is the kglat value of the first element

$markers = Array(); // we'll use this to store the marker info in the same structure
// you're using in the google.maps.create

// Now, let's loop through each item in the results and populate our $markers array
foreach($results as $i=>$m){

    // $m is just a single row from $result [a single (m)arker if you will..]
    // so $m['kmlat'] is how you access the 'kmlat' property
    // of the current row as we loop through.  $i is the row number.

    // structuring this so it matches the format you
    // need when you pass the info to google maps
    $markers[$i]['position']['lat'] = ($m['kmlat'] / 60) + $m['kglat'];  // add 'lat' value to $markers
    $markers[$i]['position']['lng'] = ($m['kmlon'] / 60) + $m['kglon'];  // add 'lng' value to $markers
    $markers[$i]['icon'] = 'cross.png';    
}

// this will format the data so javascript can use it easily
// you don't need to manualy do it.
$markers = json_encode($markers);

?>

使用Javascript：

<script>
    var markerData = <?php echo $markers ?>; //just plop in our structure data, shouldn't need to format (hopefully)

    markerData.forEach(function($i){            // we shouldn't need to format $i because json_encode did that for us
        markers[] = new google.maps.Marker($i); // 'markers' will be an array of goole map markers
    });

</script>

如何在php循环工作中使用php echo变量制作javascript？

1 个答案: