java - 需要帮助从完整的 JSON 数组/对象中提取字符串

Question

使用我正在访问的 API 的以下 JSON 输出，如何访问长城市名称“Southwest Portland”？它在对象和数组中嵌套得很深，我遇到了麻烦。

JSON:

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "3229-3353",
               "short_name" : "3229-3353",
               "types" : [ "street_number" ]
            },
            {
               "long_name" : "Southwest Dolph Court",
               "short_name" : "SW Dolph Ct",
               "types" : [ "route" ]
            },
            {
               "long_name" : "Southwest Portland",
               "short_name" : "Southwest Portland",
               "types" : [ "neighborhood", "political" ]
            },
            {
               "long_name" : "Portland",
               "short_name" : "Portland",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "Multnomah County",
               "short_name" : "Multnomah County",
               "types" : [ "administrative_area_level_2", "political" ]
            },
            {
               "long_name" : "Oregon",
               "short_name" : "OR",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "United States",
               "short_name" : "US",
               "types" : [ "country", "political" ]
            },
            {
               "long_name" : "97219",
               "short_name" : "97219",
               "types" : [ "postal_code" ]
            }
         ],

下面是我 15 次以上的编码尝试之一。每次，我都会得到不同的东西。我非常接近，我只是不太清楚如何只提取邻居名称，因为每个地址组件的标题中都有 long_name 和 short_name。感谢您的帮助!

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);

    try {

        String message = "";
        JSONObject jsonObject = new JSONObject(result);
        String JSONresults = jsonObject.getString("results");
        Log.i("JSON content", JSONresults);
        JSONArray arr = new JSONArray(JSONresults);

        for (int i = 0; i < arr.length(); i++) {

            JSONObject jsonPart = arr.getJSONObject(i);
            String neighborhoodLong = "";
            String neighborhoodShort = "";
            neighborhoodLong = jsonPart.getString("long_name");
            neighborhoodShort = jsonPart.getString("short_name");

            if (neighborhoodLong != "" && neighborhoodShort != "") {
                message += neighborhoodLong + ": " + neighborhoodShort;
            }
        }

        if (message != "") {

            Log.i("neigh", message);
            //insert succesful code here
        } else {
            //unsuccesful code goes here
        }

    } catch (JSONException e) {
            //error code here
    }



}

Answer 1

给你。我已经对代码进行了很好的注释，以便您理解。

try
            {
                    //This is the whole thing
                    JSONObject Jresult = new JSONObject(result);
                    //Now we take the JSONarray results
                    JSONArray Results = Jresult.getJSONArray("results");
                    //IMPORTANT
                    //Now we have to take the object in the array.  
                  //Since there is only 1 obj. You dont need a for loop
                    JSONObject ResObj = Results.getJSONObject(1);
                //Now we get the array address_components
                    JSONArray addressComps = ResObj.getJSONArray("address_components");
                  //Time to get the obj we want from the array
                    //Since u mentioned only thst one name and provided the result
                    //I knew the number in the array. In this case 3.
                    JSONObject needed = addressComps.getJSONObject(3);
                    //Now we get the required string
                    String longName = needed.getString("long_name");
            }
            catch (JSONException e)
            {}

一些重要的注意事项。我没有使用 for 循环，因为我们知道对象在数组中的位置。但是如果你在另一种情况下处理它，你可以使用 for 循环。你已经知道了。

另外，我可能弄错了 json 内容的字符串名称。你知道，识别名称。因此，请仔细检查以防万一。希望对您有所帮助!