java – Update elements in a JSONObject-ThrowExceptions

Exception or error:

Lets say I gave a JSONObject

{
 "person":{"name":"Sam", "surname":"ngonma"},
 "car":{"make":"toyota", "model":"yaris"}
 }

How do I update some of the values in the JSONObject?

Like below :

String name = jsonArray.getJSONObject(0).getJSONObject("person").getString("name");
name = "Sammie";
How to solve:

Use the put method: https://developer.android.com/reference/org/json/JSONObject.html

JSONObject person =  jsonArray.getJSONObject(0).getJSONObject("person");
person.put("name", "Sammie");

###

Remove key and then add again the modified key, value pair as shown below :

    JSONObject js = new JSONObject();
    js.put("name", "rai");

    js.remove("name");
    js.put("name", "abc");

I haven’t used your example; but conceptually its same.

###

Hello I can suggest you universal method. use recursion.

    public static JSONObject function(JSONObject obj, String keyMain,String valueMain, String newValue) throws Exception {
    // We need to know keys of Jsonobject
    JSONObject json = new JSONObject()
    Iterator iterator = obj.keys();
    String key = null;
    while (iterator.hasNext()) {
        key = (String) iterator.next();
        // if object is just string we change value in key
        if ((obj.optJSONArray(key)==null) && (obj.optJSONObject(key)==null)) {
            if ((key.equals(keyMain)) && (obj.get(key).toString().equals(valueMain))) {
                // put new value
                obj.put(key, newValue);
                return obj;
            }
        }

        // if it's jsonobject
        if (obj.optJSONObject(key) != null) {
            function(obj.getJSONObject(key), keyMain, valueMain, newValue);
        }

        // if it's jsonarray
        if (obj.optJSONArray(key) != null) {
            JSONArray jArray = obj.getJSONArray(key);
            for (int i=0;i<jArray.length();i++) {
                    function(jArray.getJSONObject(i), keyMain, valueMain, newValue);
            }
        }
    }
    return obj;
}

It should work. If you have questions, go ahead.. I’m ready.

###

public static JSONObject updateJson(JSONObject obj, String keyString, String newValue) throws Exception {
            JSONObject json = new JSONObject();
            // get the keys of json object
            Iterator iterator = obj.keys();
            String key = null;
            while (iterator.hasNext()) {
                key = (String) iterator.next();
                // if the key is a string, then update the value
                if ((obj.optJSONArray(key) == null) && (obj.optJSONObject(key) == null)) {
                    if ((key.equals(keyString))) {
                        // put new value
                        obj.put(key, newValue);
                        return obj;
                    }
                }

                // if it's jsonobject
                if (obj.optJSONObject(key) != null) {
                    updateJson(obj.getJSONObject(key), keyString, newValue);
                }

                // if it's jsonarray
                if (obj.optJSONArray(key) != null) {
                    JSONArray jArray = obj.getJSONArray(key);
                    for (int i = 0; i < jArray.length(); i++) {
                        updateJson(jArray.getJSONObject(i), keyString, newValue);
                    }
                }
            }
            return obj;
        }

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