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Android

Posted by Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points

JSON OBJECTS in App like a WeatherApp

Hi. I am building an app like a weather app but i am using treehouse api. I receive this error:

07-08 20:06:42.935 7022-7098/com.example.gonzalo.wordpressreader E/MainActivity: Exception caught: org.json.JSONException: No value for posts at

And this is my code:

    private Posts getCurrentDetails(String jsonData) throws JSONException {

JSONObject objeto = new JSONObject();

        JSONObject posts = objeto.getJSONObject("posts");
        Posts currentPost = new Posts();
        currentPost.setmId(posts.getString("id"));
        currentPost.setmUrl(posts.getString("url"));
        currentPost.setmTitle(posts.getString("title"));
        currentPost.setmDate(posts.getString("date"));


        currentPost.setmAuthor(posts.getString("author"));
currentPost.setmThumbnail(posts.getString("thumbnail"));

        return currentPost;
    }

i dont understand why it doesnt work

Sorry for my english. I am from Argentina.

7 Answers

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

posts is a JSONArray containing JSON objects. You cannot call getInt() or getString() on posts. You need to loop through that array, get the individual JSON objects and call those methods on those objects:

for (int i = 0 ; i < posts.length(); i++) {
    JSONObject post = posts.getJSONObject(i);
    currentPost.setmId(post.getInt("id"));
    currentPost.setmTitle(post.getString("title"));
    // etc.
}
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

The problem might be in this line of code:

JSONObject objeto = new JSONObject();

I think it should be:

JSONObject objeto = new JSONObject(jsonData);
Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points
Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points

Not really... i added jsonData but nothing happens. :(

07-08 22:17:55.964 7921-10877/com.example.gonzalo.wordpressreader E/MainActivity: Exception caught: org.json.JSONException: Value [{"id":26261,"url":"http:\/\/blog.teamtreehouse.com\/codingwisdom-start-beginner","title":"#CodingWisdom: Where to Start as a Beginner","date":"2016-07-08 02:55:00","author":"Faye Bridge","thumbnail":"http:\/\/blog.teamtreehouse.com\/wp-content\/uploads\/2016\/07\/148-150x150.jpeg"},{"id":26288,"url":"http:\/\/blog.teamtreehouse.com\/new-course-roundup-15","title":"New Course Roundup: Android, iOS, ASP.NET MVC, REST API & PostCSS","date":"2016-07-04 09:33:10","author":"Faye Bridge","thumbnail":"http:\/\/blog.teamtreehouse.com\/wp-content\/uploads\/2016\/07\/Ben-J-150x150.png"},{"id":26283,"url":"http:\/\/blog.teamtreehouse.com\/adams-story-becoming-a-professional-classical-musician-and-web-developer","title":"Meet Adam, a Professional Classical Musician and Web Developer","date":"2016-06-30 08:00:04","author":"Faye Bridge","thumbnail":"http:\/\/blog.teamtreehouse.com\/wp-content\/uploads\/2016\/06\/Adam-Hansen-150x150.jpg"},{"id":2

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

But jsonData is a String not a JSONArray. What line of code is the error referring to and what is the exact error message?

Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points
Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points

because i tried using jsonArray... the api represent the information using this mode:

<code> posts: [ { id: 26261, url: "http://blog.teamtreehouse.com/codingwisdom-start-beginner", title: "#CodingWisdom: Where to Start as a Beginner", date: "2016-07-08 02:55:00", author: "Faye Bridge", thumbnail: "http://blog.teamtreehouse.com/wp-content/uploads/2016/07/148-150x150.jpeg" },

]

</code>

Jason Anello
PLUS
Jason Anello
Courses Plus Student 94,610 Points
Jason Anello
Jason Anello
Courses Plus Student 94,610 Points

Hi Gonzaloº,

If the posts are stored in a json array then I think your code would need to be more like this:

JSONObject objeto = new JSONObject(jsonData);
JSONArray posts = objeto.getJSONArray("posts");

If this doesn't help then post the url that you're getting the data from so we can see what it looks like.

Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points
Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points

I dont understand in the Android Development Documentation tells:

JSONObject:

A modifiable set of name/value mappings. Names are unique, non-null strings. Values may be any mix of JSONObjects, JSONArrays, Strings, Booleans, Integers, Longs, Doubles or NULL. Values may not be null, NaNs, infinities, or of any type not listed here.

I tried using in my code: 

JSONObject objeto = new JSONObject(jsonData);
JSONArray posts = objeto.getJSONArray("posts");

But this stopped serving:

currentPost.setmId(posts.getInt("id"));
currentPost.setmUrl(posts.getString("url"));
currentPost.setmTitle(posts.getString("title"));
currentPost.setmDate(posts.getInt("date"));
currentPost.setmAuthor(posts.getString("author"));
currentPost.setmThumbnail(posts.getString("thumbnail"));

Which is the way I use?

Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points
Gonzaloº Caminos
Gonzaloº Caminos
2,231 Points

Thank you my friend. I solved the problem with your code. And adding this (ups!):

ButterKnife.bind(this); In onCreate method Ja.

Solved!