check for JSONObject name

Question

Here is the code im working with. Im creating a JSONArray with JSONObjects and trying to get back the JSONObjects back and the attributes:

JSONArray:

[
    {
        "test":{
            "page":"Apple",
            "ms":"234"
        }
    },
    {   
        "check":{
            "page":"Apple",
            "ms":"234"
        }
    }
]

JAVA code:

arr1 is JSONArray and contains above data;

for( int i = 0 ; i < arr1.length() ; i++ ){         
    try {
        JSONObject object = arr1.getJSONObject(i);
        //Check whether it is "test"
            JSONObject jo = object.getJSONObject("test");
            System.out.println(jo.getString("page"));
        //check whether it is "check"
            JSONObject jo = object.getJSONObject("check");
            System.out.println(jo.getString("page"));
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

What i want to know is how to check whether that first JSONObject has specified value and then go to next object. I have commented the place for the IF or SWITCH statement. Please help

http://stackoverflow.com/questions/7451600/jsonobject-how-to-get-a-value — Christophe De Troyer, Sep 29 '14 at 07:27
I already checked that. This question take the attribute if there is such object and if not error. What i want is, have a check if that element is present — Vithushan, Sep 29 '14 at 07:29
http://www.json.org/javadoc/org/json/JSONObject.html#getJSONObject(java.lang.String) — cy3er, Sep 29 '14 at 07:34

blackSmith · Accepted Answer · 2014-09-29T07:50:51.953

2

To check whether some element is present or not use JSONObject.isNull method.

 for( int i = 0 ; i < arr1.length() ; i++ ){         
   try {
       JSONObject object = arr1.getJSONObject(i);
       //Check whether it is "test"
       if( ! object.isNull("test") ){
        // do your stuff 
       }
   } catch (JSONException e) {
        e.printStackTrace();
   }
}

edited Sep 29 '14 at 07:50

answered Sep 29 '14 at 07:39

blackSmith

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check for JSONObject name

1 Answers1