map.markers未定义Google Map API v3

问题描述

好的，我有一张带有一些标记的地图。在地图上有一个点击事件应该得到最接近的标记，但是当find_closest_marker（event）函数运行时，它会在map.markers.length上中断它的未定义。

这里是一个链接到什么即时尝试 http://jsfiddle.net/VyzFq/7/

任何人都可以请显示我在哪里出错了。

解决方案

看起来有几个问题：

map.markers数组尚未被声明。

  ... 
 var infowindow =在$循环中将其标记到标记数组上。 new google.maps.InfoWindow（）; 
 
 var marker，i; 
 map.markers = []; //添加此行
（i = 0; i< locations.length; i ++）{
 marker = new google.maps.Marker（{
 position：new google.maps。 LatLng（位置[i] [1]，位置[i] [2]），
 map：map 
}）; 
 map.markers.push（marker）; //添加此行
 ... 
  

find_closest_point函数看不到地图变量。将find_closest_point函数移动到要添加click事件侦听器的作用域：

  //更改此行
 google .maps.event.addListener（地图，'click'，find_closest_marker）; 
 
 // TO：
 
 google.maps.event.addListener（map，'click'，function（event）{
 var lat = event.latLng。 lat（）; 
 var lng = event.latLng.lng（）; 
 var R = 6371; 
 var distance = []; 
 var closest = -1; 
 for（i = 0; i< map.markers.length; i ++）{
 var mlat = map.markers [i] .position.lat（）; 
 var mlng = map.markers [ i] .position.lng（）; 
 var dLat = rad（mlat  -  lat）; 
 var dLong = rad（mlng  -  lng）; 
 var a = Math.sin（dLat / 2）* Math.sin（dLat / 2）+ 
 Math.cos（rad（lat））* Math.cos（rad（lat））* Math.sin（dLong / 2）* Math.sin（dLong / 2）; 
 var c = 2 * Math.atan2（Math.sqrt（a），Math.sqrt（1-a））; 
 var d = R * c; 
距离[i] = d; 
如果（最接近== -1 || d<距离[最接近]）{
最接近= i; 
} 
} 
 
 alert（map.markers [closest] .title）; 
}）; 
  

Ok so i have a map with some markers on it. There is a click event on the map that should get the closest marker however when the find_closest_marker(event) function runs it breaks on the map.markers.length saying that its undefined.

Here is a link to what im trying to http://jsfiddle.net/VyzFq/7/

Can anyone can please show me where I'm going wrong here.

解决方案

Looks like there are a couple of problems:

1) the map.markers array hasn't been declared. declare it above the for loop, and push the markers onto the markers array.

...
var infowindow = new google.maps.InfoWindow();

var marker, i;
map.markers = []; // ADD THIS LINE
for (i = 0; i < locations.length; i++) {
    marker = new google.maps.Marker({
        position: new google.maps.LatLng(locations[i][1], locations[i][2]),
        map: map
    });
    map.markers.push(marker); // ADD THIS LINE
...

2) the find_closest_point function can't see the map variable. move the find_closest_point function to the scope where you are adding the click event listener:

// CHANGE THIS LINE
google.maps.event.addListener(map, 'click', find_closest_marker);

// TO:

google.maps.event.addListener(map, 'click', function( event ) {
    var lat = event.latLng.lat();
    var lng = event.latLng.lng();
    var R = 6371;
    var distances = [];
    var closest = -1;
    for( i=0;i<map.markers.length; i++ ) {
        var mlat = map.markers[i].position.lat();
        var mlng = map.markers[i].position.lng();
        var dLat  = rad(mlat - lat);
        var dLong = rad(mlng - lng);
        var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
            Math.cos(rad(lat)) * Math.cos(rad(lat)) * Math.sin(dLong/2) * Math.sin(dLong/2);
        var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
        var d = R * c;
        distances[i] = d;
        if ( closest == -1 || d < distances[closest] ) {
            closest = i;
        }
    }

    alert(map.markers[closest].title);
});

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