Question

我正在研究一个项目，它几乎已经完成。问题是我对Javascript很陌生，无法弄清楚如何做一些可能非常简单的事情。这是我的代码的一部分：

var dista;
var p;
var addrbounds;
var addrlat;
var addrlng;
var addr;

var icon = new google.maps.MarkerImage("http://maps.google.com/mapfiles/ms/micons/red.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();

function addMarker(lat, lng, info) {

var address = document.myform.customer.value;
var geocoder = new google.maps.Geocoder();

geocoder.geocode({address: address}, function(results, status) {

if (status == google.maps.GeocoderStatus.OK) {

var addrbounds = results[0].geometry.location; //get geocoded results into variable
var addrlat = results[0].geometry.location.lat();
var addrlng = results[0].geometry.location.lng();
var p = new google.maps.LatLng(addrlat, addrlng);
var pt1 = new google.maps.LatLng(lat, lng);

dista = pt1.distanceFrom(p); //calculate distance between the points

var di = (dista/1000);

document.myform1.memory.value = di; //add dist to memory text box

return;

} else {

alert(address + ' not found');

}

});

// desired spot for if statement regarding distance

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;

});

}

基本上它的作用是在addMarker（）函数中发生的第一件事是对地址进行地理编码，然后计算远离地址的距离。这很好用。当想要获得地理编码器的距离以创建if语句以仅在数据库中添加标记（如果它在特定半径内）时，问题就出现了。如您所见，我尝试将其移动到文本框中。这似乎有效，但它是循环的一部分，并且不会随循环的每次运行而更新。

我被困了几天所以任何帮助都会受到赞赏。我讨厌这么接近完成但是卡住了！

编辑：

我得到了它的工作。我就这样做了：

var dista;    

var p;

var addrbounds;

var addrlat;

var addrlng;

var icon = new google.maps.MarkerImage("http://maps.google.com/mapfiles/ms/micons/red.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();

function addMarker(lat, lng, info) {    

var address = document.myform.customer.value;

var geocoder = new google.maps.Geocoder();

geocoder.geocode({address: address}, function(results, status) {

  if (status == google.maps.GeocoderStatus.OK) {

  var addrbounds = results[0].geometry.location;

  var addrlat = results[0].geometry.location.lat();

  var addrlng = results[0].geometry.location.lng();

  var p = new google.maps.LatLng(addrlat, addrlng);

  var pt1 = new google.maps.LatLng(lat, lng);

  dista = pt1.distanceFrom(p);

  var di = (dista/1000);

  document.myform1.memory.value = di;

  document.myform1.memory1.value = addrlat;

  document.myform1.memory2.value = addrlng;

  return;

} else {

  alert(address + ' not found');

}

 });

var tstlat = document.myform1.memory1.value;

var tstlng = document.myform1.memory2.value;

var tstpt = new google.maps.LatLng(tstlat, tstlng);

var pt = new google.maps.LatLng(lat, lng);

var distan = pt.distanceFrom(tstpt);

var tstdistance = (distan/1000);

if (tstdistance < 20){

// alert (tstdistance);

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;

});

}

else

 {

 return;

 }}

现在我只需修复地图刷新问题，然后项目就完成了！

Answer 1

你不能获取地理编码器回调中的任何内容，地理编码强制执行异步请求，当响应到达时，你永远不会从回调外部知道。

而不是从外部获取某些内容，您必须将某些内容从回调中推送到外部（因为您已经通过设置文本框的值来完成）。您还可以从回调中调用另一个函数并提供距离作为参数。

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