Convert normal Java Array or ArrayList to Json Array in android

Question

Is there any way to convert a normal Java array or ArrayList to a Json Array in Android to pass the JSON object to a webservice?

Octavian Helm · Accepted Answer · 2012-03-05T08:53:51.330

115

If you want or need to work with a Java array then you can always use the java.util.Arrays utility classes' static asList() method to convert your array to a List.

Something along those lines should work.

String mStringArray[] = { "String1", "String2" };

JSONArray mJSONArray = new JSONArray(Arrays.asList(mStringArray));

Beware that code is written offhand so consider it pseudo-code.

edited Mar 05 '12 at 08:53

answered Mar 02 '11 at 11:34

Octavian Helm

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Is arrays.asList necessary? Even tough JSONArray has no constructor with String[] as parameter the following code works fine for me: `String[] strings = {"a", "b"}; JSONArray json = new JSONArray(strings); System.out.println(json.toString());` – M-- Aug 24 '13 at 11:04
1

Both ways work, but at least in Android, JSONArray(strings) isn't supported until API 19 – Caren Mar 31 '15 at 16:52
The way that works in the current version of java is: new JSONArray().addAll(Arrays.asList(mStringArray)) – Cody Jacques Aug 21 '17 at 18:27
No, "arrays.asList" is not necessary; otherwise, it becomes the original array in a new array of one single entry. – david m lee May 16 '18 at 23:52

score 40 · Answer 2 · answered Mar 02 '11 at 11:18

40

ArrayList<String> list = new ArrayList<String>();
list.add("blah");
list.add("bleh");
JSONArray jsArray = new JSONArray(list);

This is only an example using a string arraylist

answered Mar 02 '11 at 11:18

Reno

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Yep! Doesn't seem to work on normal String arrays though as they are not part of the Collection ( http://developer.android.com/reference/java/util/Collection.html )? But if all else fails you can just run a for loop for that. – Codemonkey Mar 02 '11 at 11:26
Try passing `Arrays.asList(stringArray)` – Ben Kane Oct 14 '13 at 14:59
`asList()` does not seem to work as I am having this problem right now – limeandcoconut May 13 '14 at 15:34

score 8 · Answer 3 · answered Sep 25 '15 at 04:59

example key = "Name" value = "Xavier" and the value depends on number of array you pass in

 try
      {
      JSONArray jArry=new JSONArray();
      for (int i=0;i<3;i++)
      {
       JSONObject jObjd=new JSONObject();
       jObjd.put("key", value);
       jObjd.put("key", value);
       jArry.put(jObjd);
      }
      Log.e("Test", jArry.toString());
      }
 catch(JSONException ex)
     {

     }

score 7 · Answer 4 · answered May 16 '18 at 23:59

7

This is the correct syntax:

String arlist1 [] = { "value1`", "value2", "value3" };
JSONArray jsonArray1 = new JSONArray(arlist1);

answered May 16 '18 at 23:59

david m lee

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score 7 · Answer 5 · answered Mar 02 '11 at 11:20

you need external library

 json-lib-2.2.2-jdk15.jar

List mybeanList = new ArrayList();
mybeanList.add("S");
mybeanList.add("b");

JSONArray jsonA = JSONArray.fromObject(mybeanList);
System.out.println(jsonA);

Google Gson is the best library http://code.google.com/p/google-gson/

score 5 · Answer 6 · answered Apr 12 '16 at 10:11

For a simple java String Array you should try

String arr_str [] = { "value1`", "value2", "value3" };

JSONArray arr_strJson = new JSONArray(Arrays.asList(arr_str));
System.out.println(arr_strJson.toString());

If you have an Generic ArrayList of type String like ArrayList<String>. then you should try

 ArrayList<String> obj_list = new ArrayList<>();
    obj_list.add("value1");
    obj_list.add("value2");
    obj_list.add("value3");
  JSONArray arr_strJson = new JSONArray(obj_list));
  System.out.println(arr_strJson.toString());

score 1 · Answer 7 · answered Feb 11 '20 at 03:53

1

My code to convert array to Json

Code

List<String>a = new ArrayList<String>();
a.add("so 1");
a.add("so 2");
a.add("so 3");
JSONArray jray = new JSONArray(a);

System.out.println(jray.toString());

output

["so 1","so 2","so 3"]

answered Feb 11 '20 at 03:53

Gim

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score 0 · Answer 8 · answered Sep 25 '20 at 09:56

Convert ArrayList to JsonArray : Like these [{"title":"value1"}, {"title":"value2"}]

Example below :

Model class having one param title and override toString method

class Model(
    var title: String,
    var id: Int = -1
){
    
    override fun toString(): String {
        return "{\"title\":\"$title\"}"
    }
}

create List of model class and print toString

var list: ArrayList<Model>()
list.add("value1")
list.add("value2")
Log.d(TAG, list.toString())

and Here is your output

[{"title":"value1"}, {"title":"value2"}]

Convert normal Java Array or ArrayList to Json Array in android

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