Convert Json Array to normal Java Array

Question

Is there a way to convert JSON Array to normal Java Array for android ListView data binding?

Answer 1

we starting from conversion [ JSONArray -> List < JSONObject > ]

public static List<JSONObject> getJSONObjectListFromJSONArray(JSONArray array) 
        throws JSONException {
  ArrayList<JSONObject> jsonObjects = new ArrayList<>();
  for (int i = 0; 
           i < (array != null ? array.length() : 0);           
           jsonObjects.add(array.getJSONObject(i++)) 
       );
  return jsonObjects;
}

next create generic version replacing array.getJSONObject(i++) with POJO

example :

public <T> static List<T> getJSONObjectListFromJSONArray(Class<T> forClass, JSONArray array) 
        throws JSONException {
  ArrayList<Tt> tObjects = new ArrayList<>();
  for (int i = 0; 
           i < (array != null ? array.length() : 0);           
           tObjects.add( (T) createT(forClass, array.getJSONObject(i++))) 
       );
  return tObjects;
}

private static T createT(Class<T> forCLass, JSONObject jObject) {
   // instantiate via reflection / use constructor or whatsoever 
   T tObject = forClass.newInstance(); 
   // if not using constuctor args  fill up 
   // 
   // return new pojo filled object 
   return tObject;
}

Answer 2

If you don't already have a JSONArray object, call

JSONArray jsonArray = new JSONArray(jsonArrayString);

Then simply loop through that, building your own array. This code assumes it's an array of strings, it shouldn't be hard to modify to suit your particular array structure.

List<String> list = new ArrayList<String>();
for (int i=0; i<jsonArray.length(); i++) {
    list.add( jsonArray.getString(i) );
}

Answer 3

How about using java.util.Arrays?

List<String> list = Arrays.asList((String[])jsonArray.toArray())

Answer 4

You can use a String[] instead of an ArrayList<String>:

Hope it helps!

   private String[] getStringArray(JSONArray jsonArray) throws JSONException {
            if (jsonArray != null) {
                String[] stringsArray = new String[jsonArray.length()];
                for (int i = 0; i < jsonArray.length(); i++) {
                    stringsArray[i] = jsonArray.getString(i);
                }
                return stringsArray;
            } else
                return null;
        }