Okay I am quering data from a Grails webservice that returns JSON. The JSON when viewed with the JSONViewer app parses fine. When I take that same string and use JSONObject(string) in my Android app I get "value of String cannot be converted to JSONObject."
Here's my JSON string
[[{"class":"mygrails.TopTen","id":491,"ttAmount":14200000,"ttMlId":402,"ttRank":1,"ttWeekId":1108},{"class":"mygrails.MovieList","id":402,"mlApproved":1,"mlApprovedId":5,"mlMovieId":"GNOMEOAN","mlReleaseDate":"2011-03-08T07:41:45Z","mlTitle":"Gnomeo and Juliet","mlWeekId":1106}]]
Now the JSON is comes from the standard JSON conversion of a SQL data using render from the groovy file through the import grails.converters.JSON.
... //(call to render JSON in the groovy file)
def a
a = Table.findAll("from someTable as st where st.id=" params.id)
render a as JSON
...
So I am not sure what I doing wrong and why the JSON looks a little off to me. (still new to JSON)
In json if you see "[]" means its a json array and if you see "{}" it is an json object. Both of then can have the other nested inside then.
In your case the string the starts with json array.
So try something like the following
String str = "[[{"class":"mygrails.TopTen","id":491,"ttAmount":14200000,"ttMlId":402,"ttRank":1,"ttWeekId":1108},{"class":"mygrails.MovieList","id":402,"mlApproved":1,"mlApprovedId":5,"mlMovieId":"GNOMEOAN","mlReleaseDate":"2011-03-08T07:41:45Z","mlTitle":"Gnomeo and Juliet","mlWeekId":1106}]]";
JSONArray jsonArray = new JSONArray(str);
jsonArray = jsonArray.getJSONArray(0);
JSONObject jsonObject = jsonArray.getJSONObject(0);
String class = jsonObject.getString("class"); // class will value "mygrails.TopTen"
Try to create an JSONArray from the String instead of JSONObject. I didn't test this but that should do the trick: you have two nested arrays that contain then actual data.
Check out your JSON online with http://jsonformat.com/
http://www.freeformatter.com/json-formatter.html
JSON Viewer
http://jsonviewer.stack.hu/
Paste your text in there and you can see what you should parse:
Related
I want to parse json from a url and use the json data with a listview.
I also want to only list the score and the name, but I have no idea how. Thanks.
{
"level":[
{
"id":1,
"server":[
{"score":33,"name":"Car"},
{"score":72,"name":"Bus"},
]
}
]
}
Do you know how to retrieve the data?
After you retrieve the data, parsing it is very simple. To get each individual item with its attributes I would use the following code:
String responseFromUrl;
JSONObject JSONResponse = new JSONObject(responseFromURL);
JSONArray level = JSONResponse.getJSONArray("level");
//The following loop goes through each object in "level". This is nessecary if there are multiple objects in "level".
for(int i=0; i<level.length(); i++){
JSONObject object = level.get(i);
int id = object.getInteger("id");
JSONArray server = object.getJSONArray("server");
//This second loop gets the score and name for each object in "server"
for(int j=0; j<server.length(); j++){
JSONObject serverObject = server.get(i);
int score = serverObject.getInteger("score");
String name = serverObject.getString("name");
}
}
Obviously replace "responseFromUrl" with the JSON response from the url in string format. If you don't know why I used JSONObject, JSONArray, String, Integer, etc., or are just confused about this, Udacity has a good course for making http connections and parsing JSON responses from APIs.
Link to Udacity Course
You can use the gson library to convert json to an java object
Download the latest jar and import into your project, currently you can download the latest at this link:
https://repo1.maven.org/maven2/com/google/code/gson/gson/2.8.1/gson-2.8.1.jar
After, this will help you:
https://stackoverflow.com/a/23071080/4508758
Hugs!
I have a scenario where I need only 1 objects out of the entire json.
{"id":"1","first_name":"Steve","last_name":"Holt","user_type":"Teacher","user_key_area":"Math"}
In above I want to extract user_type.
How will I do?
You can use Google GSON to parse the json response and map it to the model directly . Here is the tutorial for the same TUTORIAL
Use this to extract the user_type from the json, pass the your json response in place of response variable.
JsonObject object =new JsonObject(response);
String user_type = object.getString("user_type");
You are getting this json in response you can get 1 object like this:
String value = response.getString("Key Name");
Get Response and that create JsonObject
JsonObject jsonObject =new JsonObject(res);
Create String object and pass string parameter "user_type"
String userType = jsonObject.getString("user_type");
I am trying to extract data using json feed. But I get NullPointerexception due to there is no JSONObject.
I am trying to extract following data.
{"postcode":"HA0 4TL","geo": {"lat":51.55135528090932,"lng":-0.29906534560684617,"easting":518029.0,"northing":184978.0,"geohash":"http://geohash.org/gcpv30whrm0s"},"administrative":{"council":{"title":"Brent","uri":"http://statistics.data.gov.uk/id/statistical-geography/E09000005","code":"E09000005"},"ward":{"title":"Wembley Central","uri":"http://statistics.data.gov.uk/id/statistical-geography/E05000104","code":"E05000104"},"constituency":{"title":"Brent North","uri":"http://statistics.data.gov.uk/id/statistical-geography/E14000592","code":"E14000592"}}}
I can create JSONObject as follow.
String in;
JSONObject reader = new JSONObject(in);
But how can I get postcode?
Following code returns NullPointerException.
JSONObject postCode = reader.getJSONObject("postcode");
You should use
String postCode = reader.getString("postcode");
I have this class:
class Type{
public int id;
public String name;
}
and I want to format object in JSON this way
{[1,"superMarket"],[2,"restaurant "]}
and also put data from JSON to "Type" object
can some one help me please......
You can get an easy to understand example for encoding and parsing json:
Android JSON Tutorial: Create and Parse JSON data
and
JSON in Android - Tutorial
you nee to use a jasonArray and thee jsonObject ro do this..
you can viw this answer
Android create a JSON array of JSON Objects
Type to JSON
JSONObject jsonObj = new JSONObject();
jsonObj.putString("id", id);
jsonObj.putString("name", name);
You can add as many jsonObjs to JSONArray.
JSON to Type
Type type = new Type();
type.setId(jsonObj.optString("id"));
type.setName(jsonObj.optString("name"));
hello i have a JSON data format can anyone please help me to make dynamic JSONStringer object for this String
{"Text":"Hello Simple Text",
"Files":[{"ContentType":"image/png",
"Content":"iVBORw0KGgoAAAANSUhEUgAAAR8AAACMCAIAAADKsDpDAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAB3RJTUUH2wYWDzIB3zSYdQAAAAd0RVh0QXV0aG9yAKmuzEgAAAAMdEVYdERlc2NyaXB0aW9uABMJISMAAAAKdEVYdENvcHlyaWdodACsD8w6AAAADnRFWHRDcmVhdGlvbiB0aW1lADX3DwkAAAAJdEVYdFNvZnR3YXJlAF1w/zoAAAALdEVYdERpc2NsYWltZXIAt8C0jwAAAAh0RVh0V2FybmluZwDAG+aHAAAAB3RFWHRTb3VyY2UA9f+D6wAAAAh0RVh0Q29tbWVudAD2zJa/AAAABnRFWHRUaXRsZQCo7tInAAABAElEQVR4nO2de1zUVf7/3+dzmwsMoCgDXgARBO/"}],
"AuthToken":"XkWQRd65+H+iPtlOoAEYAR0jrzB1o3UV"}
i have used
jsonstr = new JSONStringer().object().key("Text")
.value(msg).key("Files").array().object().key(
"ContentType").value("image/png").key(
"Content").value(enimg)
.endObject().endArray().key("AuthToken").value(token)
.endObject();
but the server is giving me fault message in return, not accepting the data.
actually i was doing the right thing..everything was OK..
the problem was with org.json package it was not accurate with Base64 string
i switched to another library and all worked..
https://stackoverflow.com/questions/338586/a-better-java-json-library
see the above question for another json libraries
that was problem with org.json
i switched to another..and all it works
nesting too deep in JSON... should I switch to XML?
This is a way to do what you want:
// Creating root JSONObject
JSONObject json = new JSONObject();
// Put in it a String field
json.put("Text", "Hello sample");
// Creating a JSONArray
JSONArray arr = new JSONArray();
//Creating the element to populate the array
JSONObject element = new JSONObject();
element.put("ContentType","image/png");
element.put("Content","iVBORw0K...gDXgARBO/");
// Put it in the array
arr.put(element);
// Put the array and other fileds in the root JSONObject
json.put("Files", arr);
json.put("AuthToken", "XkWQ...o3UV");
// Get the JSON String
String s = json.toString();
// Get formatted and indented JSON String
String s2 = json.toString(4);
// 4 is the number of spaces to indent the string
You can use JSONObject class for this purpose
http://developer.android.com/reference/org/json/JSONObject.html