从Jquery函数获取价值 [英] Get value from Jquery function

问题描述

我一直试图返回'city'变量的值，但是我一直在寻找奇怪的结果，我知道我的代码肯定有问题，希望您能帮助我弄清楚它是什么.

I have been trying to return the value of 'city' variable but i keep geeting weird results, i know there must be something wrong with my code, i hope you can help me figure out what it is.

function getCity(lat,lng)
{
var url="http://maps.googleapis.com/maps/api/geocode/json?latlng=";
var sensor="&sensor=false";

var city;
$.getJSON(url+lat+","+lng+sensor,function(json)
    {
        var address=json.results[0].address_components;
        var addr;
        for(var i in address)
            {
                addr=address[i];
                if(addr.types[0] == "locality" && addr.types[1] == "political")
                {
                    city=addr.long_name;

                }
            }
      });
      return city;
}

推荐答案

$.getJson是一个异步函数，这意味着您要返回城市，然后执行成功函数(如果调用可行).您想要的是等待电话回来.这是我认为使用jquery deferred的一种好方法:

$.getJson is an async function, which means you are returning the city, then the success function is executed (if the call worked). What you want is to wait for the call to come back. Here's what I think is a nice way of doing this, using jquery deferred :

function getCity(lat,lng)
{
  var def = jQuery.Deferred(); 
var url="http://maps.googleapis.com/maps/api/geocode/json?latlng="
var sensor="&sensor=false";

var city;
$.getJSON(url+lat+","+lng+sensor,function(json)
    {
        var address=json.results[0].address_components;
        var addr;
        for(var i in address)
            {
                addr=address[i];
                if(addr.types[0] == "locality" && addr.types[1] == "political")
                {
                    city=addr.long_name;

                }
            }
        def.resolve(city);

      });
return def.promise();
}

$.when(getCity(40.714623,-74.006605)).then(function (city) {
 alert(city);   
});

小提琴

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