Reading multiple JSON Array in Android

Question

I asked a similar question not too long ago, but having further issues.

I have a VALID JSON Array:

However it does not read task_goalid as it is in the second part of the JSON array, error coming up as 'No Value for task_goalid'.

Any idea how to refrence the 2nd part of the JSON array?

When does the curlybrace end? for(int y=0;y<jArray.length();y++){ // <-I mean this. — Volkan
– Volkan, Commented Apr 1, 2013 at 21:49
Then look at MCeleys answer, which explains your situation... — Volkan
– Volkan, Commented Apr 1, 2013 at 22:12

ρяσѕρєя K · Accepted Answer · 2013-04-01 21:48:43Z

3

use JSONObject.has() for checking if an JSONObject contain an key or not before getting value of key from JSONObject.

for example in your case:

 String strgoalid;
 if(json_data.has("task_goalid")){

     //if json_data JSONObject contain task_goalid
   strgoalid=json_data.getString("task_goalid")
  }
  else{
    //if json_data JSONObject not contain task_goalid
    strgoalid="default value here";
  }

answered Apr 1, 2013 at 21:48

ρяσѕρєя K

133k54 gold badges203 silver badges216 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Michael Celey · Accepted Answer · 2013-04-01 21:58:49Z

1

You have a JSONArray containing two JSONObject children.

The first JSONObject has the following fields:

_id
task_name
task_day
task_priority
task_description
task_goal
user

The second JSONObject has the following fields:

_id
task_goalid
user

Since your first JSONObject doesn't not contain the task_goalid field, you won't be able to retrieve it from that object. If the field is optional, which it appears to be, you can either check if the field exists first before trying to get it using JSONObject.has("task_goalid") or get it as an optional string using JSONObject.optString("task_goalid", "No Value").

Using JSONObject.has() is the safer option here since you can definitively say whether that field exists or not. Using JSONObject.optString() allows you to assign a default value to missing fields more easily. Either method will work so it's up to you which one better suits your needs.

edited Apr 1, 2013 at 21:58

answered Apr 1, 2013 at 21:52

Michael Celey

12.7k6 gold badges61 silver badges63 bronze badges

5 Comments

user1876202 Over a year ago

I will be using multiple JSONObjects, how do I specifically get the fields from the second JSONObject?

Michael Celey Over a year ago

The second object is at index 1. To get the first object you'd use jArray.getJSONObject(0). To get the second, you'd use jArray.getJSONObject(1). Note that this isn't the best way of doing things as your array might not always be setup the same way each time. It'd be best to iterate through your array and check which object has the fields you're looking for first and only get the objects that have the required fields.

user1876202 Over a year ago

Thanks for the detailed and very clear help you have provided!Using (1) got me the goal id!

user1876202 Over a year ago

Just a quick note, I looped through all objects in the first place (0....1), you would of though it would have picked up the 'goalid' but it didnt? I have to manually refrence JSONObject(1) to get the goalid?

Michael Celey Over a year ago

If you're looping through all of them and you call json_data.getString("task_goalid") and there is no task_goalid field in the object, it'll throw an exception. This will break you out of your for loop and drop down to your catch(JSONException e) block which I assume is further down in your code.

Collectives™ on Stack Overflow

Reading multiple JSON Array in Android

2 Answers 2

Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related