How to create JSON array from JSON data file?

Question

Am new to android. Am creating an android project which parses the JSON data and displays it in a ListView. Am using Eclipse to create the project. I have created a file called userinput.json in the raw folder which is subfolder of res. I have given these JSON data inside the file.

 [
  {"name":"Company A", "hometown":"NJ"},
  {"name":"Company B", "hometown":"PA"},
  {"name":"Company C", "hometown":"CT"},
  {"name":"Company D", "hometown":"NY"},
  {"name":"Company E", "hometown":"NJ"}
  ]

My requirement is to convert this JSON data declared in the Raw resources into JSON array. Since I have declared the json data in a file, I have to access it from the resources and hence I use BufferedReader to read the file. But while trying to convert the StringBuilder object to JSON array, I am returned with null. This is the code I have written:

BufferedReader jsonReader = new BufferedReader(new InputStreamReader(
                this.getResources().openRawResource(R.raw.userinput)));
StringBuilder jsonBuilder = new StringBuilder();
try {
        for (String line = null; (line = jsonReader.readLine()) != null;)
        {
                jsonBuilder.append(line).append("\n");
        }
        jTokener = new JSONTokener(jsonBuilder.toString());
        jsonArray = new JSONArray(jTokener.toString());
    } 
    catch (Exception e) 
    {
        throw new RuntimeException(e);
    }
ArrayList<User> newArrayOfUsers = User.JsonData(jsonArray);

In a seperate Java file I have the below two methods to convert my JSON Array into Java Objects:

public User(JSONObject object)
    {
        try
        {
            this.name = object.getString(name);
            this.hometown = object.getString(hometown);
        }
        catch(JSONException e)
        {
            e.printStackTrace();
        }
    }

public static ArrayList<User> JsonData(JSONArray jsonArray)
    {
        ArrayList<User> users = new ArrayList<User>();
        for(int i = 0; i < jsonArray.length(); i++)
        {
            try
            {
                users.add(new User(jsonArray.getJSONObject(i)));
            }
            catch(JSONException e)
            {
                e.printStackTrace();
            }
        }
        return users;
    }

I am not sure, whether am doing this in correct way, Can anyone please guide me how to get JSON array from the StringBuilder?

there is no need for JSONTokener if you are using JSONArray — Selvin
– Selvin, Commented Nov 6, 2014 at 13:13
Can you please tell me how to convert the data I get in Stringbuilder object to JSONArray? — Harikrishnan
– Harikrishnan, Commented Nov 6, 2014 at 13:21
FSM save me ... in the same way as you put is into JSONTokener constructor ... Einstein was right about humans ... — Selvin
– Selvin, Commented Nov 6, 2014 at 13:22

Angad Tiwari · Accepted Answer · 2014-11-06 13:21:11Z

this works...

BufferedReader jsonReader = new BufferedReader(new InputStreamReader(
            this.getResources().openRawResource(R.raw.userinput)));
    StringBuilder jsonBuilder = new StringBuilder();
    try {
        for (String line = null; (line = jsonReader.readLine()) != null;) {
            jsonBuilder.append(line).append("\n");
        }
        Toast.makeText(this, jsonBuilder.toString(), 1).show();
        //JSONTokener jTokener = new JSONTokener(jsonBuilder.toString());
        JSONArray jsonArray = new JSONArray(jsonBuilder.toString());

        for(int i=0;i<jsonArray.length();i++)
        {
            JSONObject tmpjsonobject=jsonArray.getJSONObject(i);
            Toast.makeText(this, tmpjsonobject.getString("name")+"\n"+tmpjsonobject.getString("hometown"), 1).show();
        }
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

and @Salvin is right ...there is no need for JsonTokener .....

IgorGanapolsky · Accepted Answer · 2016-03-23 18:18:49Z

0

You can Java's Scanner class on Android to parse a raw data file and create a JSONArray. Assuming you have a file called my_raw_json.json in your res/raw dir:

    Scanner scanner = new Scanner(context.getResources().openRawResource(R.raw.my_raw_json));
    String json = scanner.useDelimiter(REGEX_INPUT_BOUNDARY_BEGINNING).next();
    JSONArray array = new JSONArray(json);

answered Mar 23, 2016 at 18:18

IgorGanapolsky

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