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Android Build a Blog Reader Android App Getting Data from the Web Parsing Data Returned in JSON Format

Omar Tsai
Omar Tsai
1,704 Points

Coding challenge question

I don't get what to do at the part where i log because i made my variable of pages but it gives me an error that i put i need to put exactly what is said into the log.

JSONChallenge.java
// JSONObject 'jsonData' was loaded from data.json
String name = jsonData.getString("name");
String publisher = jsonData.getString("publisher");
String language = jsonData.getString("language");
JSONArray jsonBooks = jsonData.getJSONArray("books");
for(int i = 0; i < jsonBooks.length(); i++){
JSONObject JsonBooks = jsonBooks.getJSONObject(i);
String pages = jsonData.getString("pages");
Log.i("CodeChallenge", pages);
  } 
data.json
{
    "name":"Treehouse Book Series",
    "publisher":"Wiley",
    "language":"English",
    "books":[
        {
            "title":"HTML5 Foundations",
            "author":"Matt West",
            "pages":384
        },
        {
            "title":"CSS3 Foundations",
            "author":"Ian Lunn",
            "pages":352
        }
    ]
}

1 Answer

Ken Alger
STAFF
Ken Alger
Treehouse Teacher

Omar;

Welcome to Treehouse! Let's take a look at this Challenge Task...

Task

Finally, write a 'for' loop that loops through 'jsonBooks'. In each step of the loop, use 'getJSONObject(int index)' to get a JSONObject from the array. Then use the 'Log.i()' method (with "CodeChallenge" as the tag) to write the book title, a comma, a space, and the number of pages. Ex. output: 'Book title 1, 300'.

Plan

It looks like you are missing a few pieces in your for loop. Here's your loop:

for(int i = 0; i < jsonBooks.length(); i++){
JSONObject JsonBooks = jsonBooks.getJSONObject(i);
String pages = jsonData.getString("pages");
Log.i("CodeChallenge", pages);

We need to get the string title, we need to add it to the object, in this case JsonBooks, we need to get pages as an int data type, and we need to format our output as requested in the challenge.

Perform

For the string title we need to use:

String title = JsonBooks.getString("title");

To add them to our object notice the use of JsonBooks instead of jsonData.

To get the pages information we use int pages and getInt instead of the String equivalent, like so:

int pages = JsonBooks.getInt("pages");

The output the challenge requested is in the format of Title, Page, so we need to adjust the formatted output to:

Log.i("CodeChallenge", title+", "+pages);

If we put it all together the, our for loop would look like:

for(int i = 0; i < jsonBooks.length(); i++){
JSONObject JsonBooks = jsonBooks.getJSONObject(i);
String title = JsonBooks.getString("title");
int pages = JsonBooks.getInt("pages");
Log.i("CodeChallenge", title+", "+pages);
  } 

I hope that helps and makes sense.

Happy coding,

Ken