如何解析从谷歌地理定位json在lng和lat中的objective-c [英] How to parse the geolocation json from google for lng and lat in objective-c

问题描述

我创建了一个web请求，以根据zip拉动lng和lat数据（使用以下url）：

http://maps.google.com/maps/geo?q=50266

这样做我回来了以下json

  {
name：50266， 
状态：{
code：200，
request：geocode
}，
地标：[{
 id：p1，
地址：美国爱达荷州西德梅因，IA 50266，
AddressDetails：{
准确性：5，
 Country：{
AdministrativeArea：{
AdministrativeAreaName：IA，
Locality：{
LocalityName：West Des Moines，
PostalCode：{
PostalCodeNumber：50266
} 
} 
}，
CountryName：USA，
CountryNameCode：US
} 
}，
ExtendedData：{ 
LatLonBox：{
north：41.6005010，
south：41.5254700，
east：-93.7347000，
west：-93.8435030 
 
 
Point：{
坐标：[-93.7353858,41,5998115,0] 
} 
}] 
} 
  

我试图从中得到的仅仅是坐标部分。这是我当前尝试抛出和异常，当我击中下面显示的最后一行

  //它到JSON和这是工作
 NSArray * json = [items JSONValue]; 
 
 NSString * coords = [json objectForKey：@Placemark.Point.coordinates]; 
  

我在这里错过了快速拉动的坐标吗？

解决方案

总体返回值不是数组，它是一个字典。请注意，第一个字符是 {。如果它是一个数组，它将是 [。

  NSDictionary * json = [string JSONValue]; 
  

现在，您需要地标键下的内容。请注意，这会返回一个数组，因为Placemarks键（和冒号）后面的字符是 [。

  NSArray * placemarks = [json objectForKey：@Placemark]; 
  

在这个数组中，您需要第一个元素，它是另一个 NSDictionary ：

  NSDictionary * firstPlacemark = [placemarks objectAtIndex：0]; 
  

在这本词典中，您希望字典在Point键下：

  NSDictionary * point = [firstPlacemark objectForKey：@Point]; 
  

从这本词典中，您需要在坐标键下的数组：

  NSArray * coordinates = [point objectForKey：@coordinates]; 
  

此时，您的数组包含3 NSNumber 对象。 Voilá！

---

对于高级用户，您可以使用键值编码来获取它：

  NSArray * coordinates = [json valueForKeyPath：@Placemark [0] .Point.coordinates]; 
  

虽然我不会建议您，除非您清楚了解发生了什么。

这是行不通的。没关系！ ：）

I'm creating a web request to pull lng and lat data based on zip (using the following url)

http://maps.google.com/maps/geo?q=50266

Doing so I get back the following json

{
  "name": "50266",
  "Status": {
    "code": 200,
    "request": "geocode"
  },
  "Placemark": [ {
    "id": "p1",
    "address": "West Des Moines, IA 50266, USA",
    "AddressDetails": {
   "Accuracy" : 5,
   "Country" : {
      "AdministrativeArea" : {
         "AdministrativeAreaName" : "IA",
         "Locality" : {
            "LocalityName" : "West Des Moines",
            "PostalCode" : {
               "PostalCodeNumber" : "50266"
            }
         }
      },
      "CountryName" : "USA",
      "CountryNameCode" : "US"
   }
},
    "ExtendedData": {
      "LatLonBox": {
        "north": 41.6005010,
        "south": 41.5254700,
        "east": -93.7347000,
        "west": -93.8435030
      }
    },
    "Point": {
      "coordinates": [ -93.7353858, 41.5998115, 0 ]
    }
  } ]
}

What I'm trying to pull from this is simply the coordinates section. Here is my current attempt that throws and exception when I hit the last line shown below

  //after I get the response I turn it into json and this is working
  NSArray* json = [items JSONValue];

  NSString* coords = [json objectForKey:@"Placemark.Point.coordinates"];

What I'm I missing here for a quick pull of the coordinates?

解决方案

The overall value return is not an array, it's a dictionary. Note that the first character is {. If it were an array, it would be [.

NSDictionary * json = [string JSONValue];

Now, you want the stuff under the "Placemarks" key. Note that this returns an array, since the character after the "Placemarks" key (and colon) is a [.

NSArray * placemarks = [json objectForKey:@"Placemark"];

From this array, you want the first element, which is another NSDictionary:

NSDictionary *firstPlacemark = [placemarks objectAtIndex:0];

From this dictionary, you want the dictionary under the key "Point":

NSDictionary *point = [firstPlacemark objectForKey:@"Point"];

From this dictionary, you want the array under the key "coordinates":

NSArray * coordinates = [point objectForKey:@"coordinates"];

At this point, you have the array that contains 3 NSNumber objects. Voilá!

---

For the advanced user, you can probably use key-value coding to get at it:

NSArray * coordinates = [json valueForKeyPath:@"Placemark[0].Point.coordinates"];

Though I wouldn't recommend that unless you clearly understand what's going on there.

That does not work. Never mind! :)

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