CODEWITHSUNDEEP
androidjsonarrays
Harikrishnan
Harikrishnan

Reputation: 21

How to create JSON array from JSON data file?

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?

Upvotes: 0

Views: 2311

Answers (2)

IgorGanapolsky
IgorGanapolsky

Reputation: 26821

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);

Upvotes: 0

Angad Tiwari
Angad Tiwari

Reputation: 1768

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 .....

Upvotes: 1

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