How to sort map of JSONObject

Question

I have a map of JSONObject and Integer. I want to sort it in an incremental order using its values, here is what I've done so far:

Map<JSONObject, Integer> unsortedMap = new HashMap<>();

unsortedMap.put(jsonObject2.getJSONObject(key),key1);

This question was answered well here: https://stackoverflow.com/questions/31158902/is-it-possible-to-sort-a-es6-map-object/31159284 — Sean Schoeman, Jan 14 '19 at 12:10
@SeanSchoeman it is in javascript can you help me do it in java / android — arfaoui rania, Jan 14 '19 at 12:23
I recommend you to use a `TreeMap` with a custom comparator. There is already a question on this topic here: https://stackoverflow.com/questions/2864840/treemap-sort-by-value — Adrian Pop, Jan 15 '19 at 09:16
Possible duplicate of [TreeMap sort by value](https://stackoverflow.com/questions/2864840/treemap-sort-by-value) — Maelig, Jan 15 '19 at 09:18

score 0 · Answer 1 · answered Jan 14 '19 at 12:36

Are you sure you want to use an Object as a key in a hashmap? It's normal practice to use immutable values for keys. The slightest change in any of the elements of the JSONObject will change the hash value and you will be unable to get your info back out of the map.

What is the integer value of your map?

Only a suggestion but you may want to check out the Java API for collection and see if there is anything that better suits your needs. Java Collection API

In the past I have wanted a sorted list with no duplicates. I had to first write to a TreeMap and then write to a SortedSet to get the result I wanted. Not code efficient, but I couldn't achieve what I wanted any other way.

score 0 · Answer 2 · answered Jan 15 '19 at 08:43

Not sure if this is the best option but could help:

public static Map<String, Integer> SortByKey(Map<String, Integer> map) 
    { 
        ArrayList<String> sortedKeys = 
                    new ArrayList<String>(map.keySet()); 

        Collections.sort(sortedKeys);  

        Map<String, Integer> sortedMap = new HashMap<>();

        for (String x : sortedKeys)  
            sortedMap.put(map.get(x), Integer.parseInt(x));

        return sortedMap;
    }

How to sort map of JSONObject

2 Answers2