Getting value from nested JSON Array via GSON on Android?

Question

Context: I'm having trouble getting a value out of a JSON returned by OpenWeatherMap's API via Android.

My JSON looks like this:

{"coord":{"lon":-78.32,"lat":38.55},"weather":[{"id":802,"main":"Clouds","description":"scattered clouds","icon":"03n"}],"base":"stations","main":{"temp":269.05,"feels_like":265.34,"temp_min":267.59,"temp_max":270.37,"pressure":1010,"humidity":78},"visibility":10000,"wind":{"speed":1.25,"deg":293},"clouds":{"all":25},"dt":1607493640,"sys":{"type":3,"id":2006561,"country":"US","sunrise":1607516385,"sunset":1607550737},"timezone":-18000,"id":4744896,"name":"Ashbys Corner","cod":200}

It is stored in a JsonObject (Part of GSON, not to be confused with JSONObject) from a URL like so:

URLConnection requestWeather = weatherUrl.openConnection();
requestWeather.connect(); // connect to the recently opened connection to the OpenWeatherMaps URL
JsonElement parsedJSON = JsonParser.parseReader(new InputStreamReader((InputStream) requestWeather.getContent())); //Convert the input stream of the URL into JSON
JsonObject fetchedJSON = parsedJSON.getAsJsonObject(); // Store the result of the parsed json locally as a json object

Problem: I want to get the value associated with "main" out of the JSON (which in this case should be "Clouds").

Attempted Solution: I've attempted to get the value of main out like this:

String weatherType = fetchedJSON.get("weather").getAsString();

but this throws a java.lang.UnsupportedOperationException: JsonObject exception.

Question: How do I get the value of "main"?

`main` is a `JsonObject` itself first you get main with `JsonObject main =fetchedJSON.getAsJsonObject("main")` then you can get inner properties of main . If you using Gson why are you still doing parsing manually ? — ADM, Dec 09 '20 at 06:56
Hmm can I call "getAsJsonObject" on "main" if "main" is nested within "weather"? — Prithvi Boinpally, Dec 09 '20 at 07:13
To be completely honest I find the answer to the question you linked a bit confusing. — Prithvi Boinpally, Dec 09 '20 at 07:13
I find it far more confusing, that this question doesn't have the least to do with GSON. — Martin Zeitler, Dec 09 '20 at 07:35
It's using GSON methods/objects like "JsonElement, JsonObject, JsonParser" etc. And one of GSON's various get methods I suspect is the solution to my problem. — Prithvi Boinpally, Dec 09 '20 at 07:36

Vishal Chauhan · Accepted Answer · 2020-12-09T07:37:08.810

1

You can use JACKSON or GSON library for fast parsing of Json data using model class. JACKSON and GSON are dedicated to processing (serializing/deserializing) JSON data.

Raw Parsing via GSON

JsonObject fetchedJSON = parsedJSON.getAsJsonObject();
//weather is an array so get it as array not as string
JsonArray jarray = fetchedJSON.getAsJsonArray("weather");
// OR you use loop if you want all main data
jobject = jarray.get(0).getAsJsonObject();
String main= jobject.get("main").getAsString();

Although if you want raw parsing then you can do like ::

JSONObject obj = new JSONObject(yourString);

JSONArray weather = obj.getJSONArray("weather");
for (int i = 0; i < arr.length(); i++)
{
String main= arr.getJSONObject(i).getString("main");
......
}

edited Dec 09 '20 at 07:37

answered Dec 09 '20 at 07:23

Vishal Chauhan

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As I stated in the question, I'm already using GSON. Do you know of a way to get the value of "main" from the JSON via GSON's methods? – Prithvi Boinpally Dec 09 '20 at 07:28
1

@PrithviBoinpally check now – Vishal Chauhan Dec 09 '20 at 07:37
[JSONObject](https://developer.android.com/reference/org/json/JSONObject) has nothing to do with GSON. Neither the question nor the answer use it. Better use GSON with ORM and skip all of that manually messing around... and map it instead. – Martin Zeitler Dec 09 '20 at 08:24
@MartinZeitler Yes..I know JSONObject nothing to do with GSON that why I wrote raw parsing and also wrote JACKSON and GSON library for fast parsing of Json data using model class(ORM). – Vishal Chauhan Dec 09 '20 at 09:33
But I'm not using JSONObject, I'm using JsonObject. GSON uses the lowercase version. – Prithvi Boinpally Dec 09 '20 at 09:35
1

@PrithviBoinpally I also gave your answer with JsonObject (GSON). I just wrote another option of json data parsing with JSONObject. – Vishal Chauhan Dec 09 '20 at 09:40
Yes, sorry I was replying to Martin, not you. Thank you for your update. – Prithvi Boinpally Dec 09 '20 at 18:51

Getting value from nested JSON Array via GSON on Android?

1 Answers1