Java Android - How to sort a JSONArray based on keys

Question

I'm getting this string (from a webservice) into a JSONArray like this,

[
 {
  "lat": "-16.408545",
  "lon": "-71.539105",
  "type": "0",
  "distance": "0.54"
 },
 {
  "lat": "-16.4244317845",
  "lon": "-71.52562186",
  "type": "1",
  "distance": "1.87"
 },
 {
  "lat": "-16.4244317845",
  "lon": "-71.52562186",
  "type": "1",
  "distance": "0.22"
 }
]

I need to sort it by the distance key to show the nearest first and farthest last. I didn't try any code because I really don't have any ideas. I'm not using the GSON library, I'm using org.json.JSONArray.

use undercore.js library , you have various sorting solutions are with it. — Nomesh DeSilva
– Nomesh DeSilva, Commented Aug 5, 2015 at 10:04

crysis · Accepted Answer · 2015-08-05 09:51:15Z

8

First parse your array in a list

JSONArray sortedJsonArray = new JSONArray();
List<JSONObject> jsonList = new ArrayList<JSONObject>();
for (int i = 0; i < jsonArray.length(); i++) {
    jsonList.add(jsonArray.getJSONObject(i));
}

then use collection.sort to sort the newly created list

Collections.sort( jsonList, new Comparator<JSONObject>() {

    public int compare(JSONObject a, JSONObject b) {
        String valA = new String();
        String valB = new String();

        try {
            valA = (String) a.get("distance");
            valB = (String) b.get("distance");
        } 
        catch (JSONException e) {
            //do something
        }

        return valA.compareTo(valB);
    }
});

Insert the sorted values in your array

for (int i = 0; i < jsonArray.length(); i++) {
    sortedJsonArray.put(jsonList.get(i));
}

answered Aug 5, 2015 at 9:51

crysis

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2 Comments

Manish Over a year ago

plz see this how to sort listview by name

Prabs Over a year ago

to switch among the order --> valA.compareTo(valB) vs valB.compareTo(valA)

Nitesh · Accepted Answer · 2015-08-05 09:39:50Z

0

Parse your json object into a model say array-List and sort it using comparator.

ArrayList<ClassObject> dataList = new ArrayList<String>();
JSONArray array = new JSONArray(json);     
for(Object obj : jsonArray){
   dataList.add(//your data model);
}

Please refer this link for sorting of array-list http://java2novice.com/java-collections-and-util/arraylist/sort-comparator/

edited Aug 5, 2015 at 9:39

answered Aug 5, 2015 at 9:33

Nitesh

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Comments

nomanr · Accepted Answer · 2015-08-05 09:52:10Z

Try this. It should work

ArrayList<JSONObject> array = new ArrayList<JSONObject>();
JSONArray jsonArray = new JSONArray();
for (int i = 0; i < jsonArray.length(); i++) {
   try {
       array.add(jsonArray.getJSONObject(i));
   } catch (JSONException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
   }
}   

Collections.sort(array, new Comparator<JSONObject>() {

@Override
public int compare(JSONObject lhs, JSONObject rhs) {
    // TODO Auto-generated method stub

    try {
        return (lhs.getDouble("distance").compareTo(rhs.getDouble("distance")));
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return 0;
    }
}
});

And after this you can convert sorted ArrayList array into JSONArray.

JSONArray jsonArray = new JSONArray(array);
String jsonArrayStr = jsonArray.toString();

Md. Arif · Accepted Answer · 2023-01-26 19:57:02Z

0

In kotlin you can do as below

Parse your array in a list

val sortedJsonArray = JSONArray()
val jsonList = ArrayList<JSONObject>()
for (i in 0 until jsonArray.length()) {
    jsonList.add(jsonArray.getJSONObject(i))
}

Sort the newly created list

jsonList.sortWith { a, b ->
    var valA = String()
    var valB = String()
    try {
        valA = a.get("distance") as String
        valB = b.get("distance") as String
    } catch (e: JSONException) {
        e.printStackTrace()
    }
    valA.compareTo(valB)
}

Insert the sorted values in your json array

for (i in 0 until jsonArray.length()) {
    sortedJsonArray.put(jsonList[i])
}

Thanks to @crysis for his answer.

answered Jan 26, 2023 at 19:57

Md. Arif

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