Convert Normal Java Array or Arraylist to JSON Array in Android

Convert normal Java Array or ArrayList to Json Array in android

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.

Converting JSONarray to ArrayList

ArrayList<String> listdata = new ArrayList<String>();     
JSONArray jArray = (JSONArray)jsonObject; 
if (jArray != null) { 
   for (int i=0;i<jArray.length();i++){ 
    listdata.add(jArray.getString(i));
   } 
} 

convert ArrayListMyCustomClass to JSONArray

If I read the JSONArray constructors correctly, you can build them from any Collection (arrayList is a subclass of Collection) like so:

ArrayList<String> list = new ArrayList<String>();
list.add("foo");
list.add("baar");
JSONArray jsArray = new JSONArray(list);

References:

• jsonarray constructor:
  http://developer.android.com/reference/org/json/JSONArray.html#JSONArray%28java.util.Collection%29
• collection:
  http://developer.android.com/reference/java/util/Collection.html

How to convert ArrayList of custom class to JsonArray in Java?

Below code should work for your case.

List<Customer> customerList = CustomerDB.selectAll();

Gson gson = new Gson();
JsonElement element = gson.toJsonTree(customerList, new TypeToken<List<Customer>>() {}.getType());

if (! element.isJsonArray() ) {
// fail appropriately
    throw new SomeException();
}

JsonArray jsonArray = element.getAsJsonArray();

Heck, use List interface to collect values before converting it JSON Tree.

Convert Json Array to normal Java list

ArrayList<String> list = new ArrayList<String>();     
JSONArray jsonArray = (JSONArray)jsonObject; 
if (jsonArray != null) { 
   int len = jsonArray.length();
   for (int i=0;i<len;i++){ 
    list.add(jsonArray.get(i).toString());
   } 
} 

How to convert Arraylist to Json in Java

Not sure if it's exactly what you need, but you can use the GSON library (Link) for ArrayList to JSON conversion.

ArrayList<String> list = new ArrayList<String>();
list.add("str1");
list.add("str2");
list.add("str3");
String json = new Gson().toJson(list);

Or in your case:

ArrayList<Domain> list = new ArrayList<Domain>();
list.add(new Domain());
list.add(new Domain());
list.add(new Domain());
String json = new Gson().toJson(list);

If for some reason you find it more convenient, you can also iterate through the ArrayList and build a JSON from individual Domain objects in the list

String toJSON(ArrayList<Domain> list) {
    Gson gson = new Gson();
    StringBuilder sb = new StringBuilder();
    for(Domain d : list) {
        sb.append(gson.toJson(d));
    }
    return sb.toString();
}

Convert JSON array to Java Class Object List

Try this:

    try {            
         JSONObject jsonObject = null;
         yourJSONString.replace("\\", "");
         jsonObject = new JSONObject(yourJSONString);
         String newJSONString = jsonObject.get("GetCardsResult").toString();
         JSONArray jsonMainArr = new JSONArray(newJSONString);
         //now just loop the json Array
         for (int i = 0; i < jsonMainArr.length(); ++i) {                     
         JSONObject rec = jsonMainArr.getJSONObject(i);                     
         card.set_id(rec.get("ID").toString());                     
         //....      
       }                                                       
       } catch (JSONException e) {
         e.printStackTrace();
       } 

How to convert a jsonArray into ListString Java?

I assume JSONArray comes from Android. You can just do this:

ArrayList<String> list = new ArrayList<String>();
JSONArray jsonArray = (JSONArray)jsonObject;
if (jsonArray != null) {
    int len = jsonArray.length();
    for (int i=0;i<len;i++){
        list.add(jsonArray.get(i).toString());
    }
}

Source: Convert Json Array to normal Java list

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