How to check if json array has any value?

Question

I am using the condition -

if (!obj2.getString("patronCheckoutInfo").equals("null")) {

But it does not work for the case when array got the value.

Eg: Case1- when json got value for "patronCheckoutInfo":

{
"ErrorMessage": ""
"Message": "Operation completed successfully"
"Status": "OK"
"Results": {
"LookupPatronInfoResponse": {
"patronAddressInfo": null
"patronCheckoutHistoryInfo": null
"patronCheckoutInfo": [6]
0:  {
"author": "Cobb, Kevin."

Case 2 - when no value:

{
"ErrorMessage": ""
"Message": "Operation completed successfully"
"Status": "OK"
"Results": {
"LookupPatronInfoResponse": {
"patronAddressInfo": null
"patronCheckoutHistoryInfo": null
"patronCheckoutInfo": null
"patronCirculationInfo": null

Tried few tutorials but unable to figure out. Any suggestion is welcome. Thanks in advance.

Use optJSONArray(String name) returns value if it exists or null otherwise — Raghunandan
– Raghunandan, Commented Mar 17, 2016 at 8:30
Try checking like if (!obj2.getString("patronCheckoutInfo") == null)... Because null is not a string to check like that... — Shree Krishna
– Shree Krishna, Commented Mar 17, 2016 at 8:34
@Raghunandan please convert this into an answer. I'm sure that it will solve OPs question — Desdroid
– Desdroid, Commented Mar 17, 2016 at 9:20

toantran · Accepted Answer · 2016-03-17 08:29:31Z

3

You can use support function isNull (http://developer.android.com/reference/org/json/JSONObject.html#isNull(java.lang.String))

So, re-write your code in this case:

if (!obj2.isNull("patronCheckoutInfo")) {
// do something 
}

answered Mar 17, 2016 at 8:29

toantran

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3 Comments

snachmsm Over a year ago

also you might use has(), but question author have this field in both JSONs

toantran Over a year ago

@snachmsm but the document said Returns true if this object has no mapping for name or if it has a mapping whose value is NULL. In this case, both json response had this key, so if in case of the value of second json response had NULL value, it should return true. Right?

Dep Over a year ago

This condition is returning - false - even for values in patronCheckoutInfo. Not working.

Swaminathan V · Accepted Answer · 2016-03-17 08:32:26Z

2

Yes, you can check if the particular key present in the Json.

Its pretty simple..!! Try this..

boolean response = jsonobject.has("patronCheckoutInfo")

Hope this will help you, Happy coding

answered Mar 17, 2016 at 8:32

Swaminathan V

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2 Comments

Dep Over a year ago

it will return true in both cases.

Swaminathan V Over a year ago

you need to specify the jsonobject that contains the particular key.

Amy · Accepted Answer · 2016-03-17 08:32:55Z

2

Try This:

if(obj2.has("patronCheckoutInfo")){
//write your code
}

answered Mar 17, 2016 at 8:32

Amy

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Comments

Deepak Goyal · Accepted Answer · 2016-03-17 08:33:35Z

0

Try with

if (!obj2.getString("patronCheckoutInfo").equals("null"))

to

String patronCheckoutInfo = obj2.getString("patronCheckoutInfo");
if(!TextUtils.isEmpty(patronCheckoutInfo)){
  // string has value
}else{
  // string is empty
}

answered Mar 17, 2016 at 8:33

Deepak Goyal

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4 Comments

Dep Over a year ago

Its empty but still going into the loop. Not working.

Dep Over a year ago

patronCheckoutInfo got no values - but condition results in true.

Deepak Goyal Over a year ago

print out the patronCheckoutInfo String and let me know what it gives.

Dep Over a year ago

Here you go --> I/patronCheckoutInfo: null

Dep · Accepted Answer · 2016-03-18 01:42:30Z

0

Thanks all for the suggestion. Below worked for me:

if (obj2.getString("patronCheckoutInfo") != null)

answered Mar 18, 2016 at 1:42

Dep

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Comments

Andan H M · Accepted Answer · 2016-03-19 07:47:37Z

0

You can try like this:

JSONArray patronCheckoutInfo= obj2.optJSONArray("patronCheckoutInfo");
if(patronCheckoutInfo){
        for (int i = 0; i < invitations.length(); i++) {
              JSONObject patronCheckoutInfoObject= patronCheckoutInfo.getJSONObject(i);
        }
}

answered Mar 19, 2016 at 7:47

Andan H M

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