JSONObject parsing error when there is no value

Question

I have a JSON which looks like this:

{
"notifications": {
    "0": {
        "id": "27429",
        "uID": "6967",
        "text": "Text 1"
    },
    "1": {
        "id": "27317",
        "uID": "6967",
        "text": "Text 2"
    },
    "2": {
        "id": "27315",
        "uID": "6967",
        "text": "Text 3"
    },
    "3": {
        "id": "27314",
        "uID": "6967",
        "text": "Text 4"
    },
    "4": {
        "id": "27312",
        "uID": "6967",
        "text": "Text 5"
    }
}
}

I'm taking out "text" string from the response, for this my code looks like this:

JSONObject rootObj = new JSONObject(result);
JSONObject jSearchData = rootObj.getJSONObject("notifications");

int maxlimit = 4;

for (int i = 0; i < maxlimit; i++) {
    JSONObject jNotification0 = jSearchData.getJSONObject("" + i + "");

    String text = jNotification0.getString("text");

    System.out.println("Text: " + text);
}

For now this works perfectly fine, I get all the 4 "text" in the logs.

Now, my problem is that when I get response from server with only 1 or 2 data, something like this:

{
"notifications": {
    "0": {
        "id": "27429",
        "uID": "6967",
        "text": "Only one text here"
    }
}
}

Then my above logic fails, I get exception stating org.json.JSONException: No value for 1

How can I overcome this problem.

Any kind of help will be appreciated.

instead iterating `i` iterate through [JSONObject.keys()](http://developer.android.com/reference/org/json/JSONObject.html#keys()) — Selvin, Jul 05 '13 at 12:42
@Selvin How can I do that, can you give me an example for that. — Anupam, Jul 05 '13 at 12:51
pseudocode: `var keys = jSearchData.keys(); for(key in keys){var jNotificationX = jSearchData.getJSONObject(key);}` — Selvin, Jul 05 '13 at 12:53

Blackbelt · Accepted Answer · 2013-07-05T13:14:00.390

you can test if a key exists with rootObj.has("1") or use rootObj.optJSONObject("1");

the former returns true if this object has a mapping for name. The latter returns the value mapped by name if it exists and is a JSONObject, null otherwise.

Or you can interate through the keys inside rootObj, this way:

Iterator<String> keys = jSearchData.keys();
while (keys.hasNext()) {
      String key = keys.next();
      JSONObject jNotification0 = jSearchData.optJSONObject(key);
      if (jNotification0 != null) {
           String text = jNotification0.getString("text");
           String uID = jNotification0.getString("uID");
           String id = jNotification0.getString("id");
      }
}

okay thanks for the answer, but I'm not getting how to implement this with the present code. As you can see I have for loop, how can I use keys in that? — Anupam, Jul 05 '13 at 13:11

Anton Aderum · Answer 2 · 2013-07-05T13:20:56.073

-1

Edit: This is wrong, I read to fast and did not realize jSearchData was an object and not an array. But in my opinion if would make a lot more sense if it was in fact an array instead of an object.

There's no need to hard code the 4. Just take the length of the array and loop through it, like this:

for (int i = 0; i < jSearchData.length(); i++) {
    JSONObject jNotification0 = jSearchData.getJSONObject("" + i + "");

    String text = jNotification0.getString("text");

    System.out.println("Text: " + text);
}

edited Jul 05 '13 at 13:20

answered Jul 05 '13 at 12:37

Anton Aderum

27
3

As you can see `jSearchData` is `JSONObject`. It looks like this. `JSONObject jSearchData = rootObj.getJSONObject("notifications");` How can we use this in `for loop`. – Anupam Jul 05 '13 at 12:40

JSONObject parsing error when there is no value

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