Get JSONArray without array name?

Question

I'm new to JSON and trying this tutorial: http://p-xr.com/android-tutorial-how-to-parse-read-json-data-into-a-android-listview/#comments

I'm new to JSON, C languages, Java and also Android, but am learning. The tutorial uses what I'm calling a named array, but all of the JSON i'm going to be using in my android project will use simple table rows with no named array. Examples of the JSON i'm using and the earthquake json from the tutorial are below.

The tutorial iterates through the earthquake array and converts into a JAVA hashmap list using the following code:

JSONArray  earthquakes = json.getJSONArray("earthquakes");
    for(int i=0;i<earthquakes.length();i++){                        
        HashMap<String, String> map = new HashMap<String, String>();    
        JSONObject e = earthquakes.getJSONObject(i);

        map.put("id",  String.valueOf(i));
        map.put("name", "Earthquake name:" + e.getString("eqid"));
        map.put("magnitude", "Magnitude: " +  e.getString("magnitude"));
        mylist.add(map);            
}

My question is, how can I use json.getJSONArray("") if my JSON is just simple as below? I can convert the rest of the code, I just need to know how to load that JSON using the getJSONArray("strJsonArrayName") if I don't have a strJsonArrayName.

My JSON (UnNamed Array)

[
  {
    "cnt":1,
    "name":"American",
    "pk":7
  },
  {
    "cnt":2,
    "name":"Celebrities",
    "pk":3
  },
  {
    "cnt":1,
    "name":"Female",
    "pk":2
  },
  {
    "cnt":1,
    "name":"Language",
    "pk":8
  },
  {
    "cnt":1,
    "name":"Male",
    "pk":1
  },
  {
    "cnt":1,
    "name":"Region",
    "pk":9
  }
]

Tutorial's JSON (Named Array)

{
  "earthquakes":[
    {
      "eqid":"c0001xgp",
      "magnitude":8.8,
      "lng":142.369,
      "src":"us",
      "datetime":"2011-03-11 04:46:23",
      "depth":24.4,
      "lat":38.322
    },
    {
      "eqid":"c000905e",
      "magnitude":8.6,
      "lng":93.0632,
      "src":"us",
      "datetime":"2012-04-11 06:38:37",
      "depth":22.9,
      "lat":2.311
    },
    {
      "eqid":"2007hear",
      "magnitude":8.4,
      "lng":101.3815,
      "src":"us",
      "datetime":"2007-09-12 09:10:26",
      "depth":30,
      "lat":-4.5172
    },
    {
      "eqid":"c00090da",
      "magnitude":8.2,
      "lng":92.4522,
      "src":"us",
      "datetime":"2012-04-11 08:43:09",
      "depth":16.4,
      "lat":0.7731
    },
    {
      "eqid":"2007aqbk",
      "magnitude":8,
      "lng":156.9567,
      "src":"us",
      "datetime":"2007-04-01 18:39:56",
      "depth":10,
      "lat":-8.4528
    },
    {
      "eqid":"2007hec6",
      "magnitude":7.8,
      "lng":100.9638,
      "src":"us",
      "datetime":"2007-09-12 21:49:01",
      "depth":10,
      "lat":-2.5265
    },
    {
      "eqid":"a00043nx",
      "magnitude":7.7,
      "lng":100.1139,
      "src":"us",
      "datetime":"2010-10-25 12:42:22",
      "depth":20.6,
      "lat":-3.4841
    },
    {
      "eqid":"2010utc5",
      "magnitude":7.7,
      "lng":97.1315,
      "src":"us",
      "datetime":"2010-04-06 20:15:02",
      "depth":31,
      "lat":2.3602
    },
    {
      "eqid":"2009mebz",
      "magnitude":7.6,
      "lng":99.9606,
      "src":"us",
      "datetime":"2009-09-30 08:16:09",
      "depth":80,
      "lat":-0.7889
    },
    {
      "eqid":"2009kdb2",
      "magnitude":7.6,
      "lng":92.9226,
      "src":"us",
      "datetime":"2009-08-10 17:55:39",
      "depth":33.1,
      "lat":14.0129
    }
  ]
}

In the tutorial, based on the answers from @MДΓΓ БДLL and @Cody Caughlan , I was able to reformat the JSONFunctions.getJSONFromURL into a JSONArray instead of a JSONObject. Here is my modified working code, thank you!

public class JSONfunctions {
public static JSONArray getJSONfromURL(String url){
    InputStream is = null;
    String result = "";
    JSONArray jArray = null;

            HttpClient httpclient = new DefaultHttpClient();
            HttpGet httpget = new HttpGet(url);
            HttpResponse response = httpclient.execute(httpget);
            HttpEntity entity = response.getEntity();
            is = entity.getContent();

            BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
            }
            is.close();
            result=sb.toString();

        jArray = new JSONArray(result);            
    return jArray;
}
}

score 150 · Accepted Answer · answered Apr 15 '12 at 18:25

150

You don't need to call json.getJSONArray() at all, because the JSON you're working with already is an array. So, don't construct an instance of JSONObject; use a JSONArray. This should suffice:

// ...
JSONArray json = new JSONArray(result);
// ...

for(int i=0;i<json.length();i++){                        
    HashMap<String, String> map = new HashMap<String, String>();    
    JSONObject e = json.getJSONObject(i);

    map.put("id",  String.valueOf(i));
    map.put("name", "Earthquake name:" + e.getString("eqid"));
    map.put("magnitude", "Magnitude: " +  e.getString("magnitude"));
    mylist.add(map);            
}

You can't use exactly the same methods as in the tutorial, because the JSON you're dealing with needs to be parsed into a JSONArray at the root, not a JSONObject.

answered Apr 15 '12 at 18:25

Matt Ball

354,903
100
647
710

1

OK, I get it. I converted the getJSONObject method into a getJSONArray method like so and also changed his httpPost into a httpGet and it's working now! Thanks you! – Ricky Apr 15 '12 at 19:04
Can u tell me what is that result depicts in?JSONArray json = new JSONArray(result); – Sharath Jul 28 '15 at 07:39
Nope will do! @MattBall – Sharath Jul 28 '15 at 12:57
how do i set my java model class if i have an un-named json array? – Kaveesh Kanwal Aug 14 '15 at 10:57
@KaveeshKanwal use a List/Set/Collection/array of whatever's in the JSON array. – Matt Ball Aug 14 '15 at 12:52

score 8 · Answer 2 · answered Apr 15 '12 at 18:24

8

JSONArray has a constructor which takes a String source (presumed to be an array).

So something like this

JSONArray array = new JSONArray(yourJSONArrayAsString);

answered Apr 15 '12 at 18:24

Cody Caughlan

32,456
5
63
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exactly, but my JSON doesn't have an array name. What do I put in yourJSONArrayAsString? Are you saying I should just pass my entire JSON output string as a parameter? – Ricky Apr 15 '12 at 18:26
OK, i think I get what you are saying, please confirm: I use the new JSONArray you are mentioning as the parameter instead of "earthquakes" – Ricky Apr 15 '12 at 18:27
@Ricky that's not quite right. You need the `getJSONfromURL()` method to return a `JSONArray`, not a `JSONObject`. – Matt Ball Apr 15 '12 at 18:30

score 0 · Answer 3 · answered Aug 15 '13 at 10:39

I've assumed a named JSONArray is a JSONObject and accessed the data from the server to populate an Android GridView. For what it is worth my method is:

private String[] fillTable( JSONObject jsonObject ) {
   String[] dummyData = new String[] {"1", "2", "3", "4", "5", "6", "7","1", "2", "3", "4", "5", "6", "7","1", "2", "3", "4", "5", "6", "7", };
  if( jsonObject != null ) {
      ArrayList<String> data = new ArrayList<String>();
      try {
          // jsonArray looks like { "everything" : [{}, {},] }
          JSONArray jsonArray = jsonObject.getJSONArray( "everything" );
          int number = jsonArray.length(); //How many rows have got from the database?
          Log.i( Constants.INFORMATION, "Number of ows returned:  " + Integer.toString( number ) );
                  // Array elements look like this
          //{"success":1,"error":0,"name":"English One","owner":"Tutor","description":"Initial Alert","posted":"2013-08-09 15:35:40"}
          for( int element = 0; element < number; element++ ) { //visit each element
             JSONObject jsonObject_local = jsonArray.getJSONObject( element );
             //  Overkill on the error/success checking
             Log.e("JSON SUCCESS", Integer.toString( jsonObject_local.getInt(Constants.KEY_SUCCESS) ) );
             Log.e("JSON ERROR", Integer.toString( jsonObject_local.getInt(Constants.KEY_ERROR) ) );
                if ( jsonObject_local.getInt( Constants.KEY_SUCCESS) == Constants.JSON_SUCCESS ) {
                   String name = jsonObject_local.getString( Constants.KEY_NAME );
                   data.add( name );
                   String owner = jsonObject_local.getString( Constants.KEY_OWNER );
                   data.add( owner );
                   String description = jsonObject_local.getString( Constants.KEY_DESCRIPTION );
                   Log.i( "DESCRIPTION", description );
                   data.add( description ); 
                   String date = jsonObject_local.getString( Constants.KEY_DATE );
                   data.add( date );
                }
                else {
                    for( int i = 0; i < 4; i++ ) {
                        data.add( "ERROR" );
                    }
                }
          }
  }  //JSON object is null
  catch ( JSONException jsone) {
      Log.e( "JSON EXCEPTION", jsone.getMessage() );
  }
      dummyData = data.toArray( dummyData );
  }
  return dummyData;

}

score 0 · Answer 4 · answered Oct 02 '15 at 15:14

Here is a solution under 19API lvl:

First of all. Make a Gson obj. --> Gson gson = new Gson();
Second step is get your jsonObj as String with StringRequest(instead of JsonObjectRequest)
The last step to get JsonArray...

YoursObjArray[] yoursObjArray = gson.fromJson(response, YoursObjArray[].class);

Get JSONArray without array name?

4 Answers4

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