javascript 如何正确使用computeDistanceBetween()？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/6754085/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to use computeDistanceBetween() correctly?
提问by celsowm
I am newbie in Maps API, i am trying get the distance (in Km) from 2 adress. What is wrong with this code?
我是 Maps API 的新手，我正在尝试从 2 个地址获取距离（以公里为单位）。这段代码有什么问题？
var mygc = new google.maps.Geocoder();
var locationOrigem;
var locationDestino;
var latOrigem = 0;
var longOrigem = 0;
var latDestino = 0;
var longDestino = 0;
mygc.geocode({'address' : 'Presidente Vargas 897, Centro RJ'}, function(results, status){
locationOrigem = results[0].geometry.location;
latOrigem = results[0].geometry.location.lat();
longOrigem = results[0].geometry.location.lng();
});
mygc.geocode({'address' : 'Abelardo Bueno 3000, Barra da Tijuca RJ'}, function(results, status){
locationDestino = results[0].geometry.location;
latDestino = results[0].geometry.location.lat();
longDestino = results[0].geometry.location.lng();
});
alert(google.maps.geometry.spherical.computeDistanceBetween(locationOrigem, locationDestino));
By a unknown reason, var locationOrigem and locationDestinoare "undefined" outside of anonymous functions ??? Why???
由于未知原因，var locationOrigem 和 locationDestino在匿名函数之外是“未定义的”？？？为什么？？？
回答by Ruslan Polutsygan
Have you included this script?
你有没有包含这个脚本？
<script type="text/javascript" src="http://maps.google.com/maps/api/js?libraries=geometry&sensor=false&language=en"></script>
What happen when you run your code? Are you sure that your addresses were geocoded correctly? Are you sure that problem is in computeDistanceBetween. Try to dump all variables.
运行代码时会发生什么？您确定您的地址已正确进行地理编码吗？你确定问题出在computeDistanceBetween. 尝试转储所有变量。
UPDATE:
更新：
Requests to the Geocoder are executed asynchronously. So request for distance calculation were run before you had got geocoded data. That is why your variables were undefined. You need to use callbacks to ensure that request is finished. Try this code
对地理编码器的请求是异步执行的。因此在您获得地理编码数据之前运行距离计算请求。这就是为什么你的变量是undefined. 您需要使用回调来确保请求完成。试试这个代码
var mygc = new google.maps.Geocoder();
var locationOrigem;
var locationDestino;
var latOrigem = 0;
var longOrigem = 0;
var latDestino = 0;
var longDestino = 0;
mygc.geocode({'address' : 'Presidente Vargas 897, Centro RJ'}, function(results, status){
locationOrigem = results[0].geometry.location;
latOrigem = results[0].geometry.location.lat();
longOrigem = results[0].geometry.location.lng();
mygc.geocode({'address' : 'Abelardo Bueno 3000, Barra da Tijuca RJ'}, function(results, status){
locationDestino = results[0].geometry.location;
latDestino = results[0].geometry.location.lat();
longDestino = results[0].geometry.location.lng();
console.log(locationOrigem);
console.log(locationDestino);
console.log(google.maps.geometry.spherical.computeDistanceBetween(locationOrigem, locationDestino));
});
});
Also you need to check status of response. I haven't include because it is not the subject.
您还需要检查响应状态。我没有包括，因为它不是主题。
