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Android Build a Weather App (2015) Working with JSON Using JSONObject

Orla McGreal
Orla McGreal
1,625 Points
Posted by Orla McGreal
Orla McGreal
1,625 Points

Need help with the challenge- I don't get how to set the variables using the jsonData object...

I understand the variables and their appropriate values but don't understand how to set them in the object that's already been made elsewhere.

Could somebody explain?

Thanks in advance!

JSONChallenge.java 
// A JSONObject variable named 'jsonData'
// was loaded from the data.json file.


private jsonData () {
 private String name;
private String publisher;
private String language;

}
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
        }
    ]
}

2 Answers

Steve Hunter
Steve Hunter
57,712 Points

Hi there,

You can take each element and use getString() to access the value for each key, like so: 

String name = jsonData.getString("name");
String publisher = jsonData.getString("publisher");
String language = jsonData.getString("language");

Hope that helps!

Steve

Orla McGreal
Orla McGreal
1,625 Points
Orla McGreal
Orla McGreal
1,625 Points

That does - thanks !

CD Lim
CD Lim
4,782 Points
CD Lim
CD Lim
4,782 Points

Hi Steve, I was trying to create a new object and link to it just as it is shown in the tutorial, may I ask why it does not work ? 

JSONObject books = new JSONObject (jsonData);
String name= books.getString ("name");
String publisher= books.getString ("publisher");
String language= books.getString ("language");
Steve Hunter
Steve Hunter
57,712 Points

HIya,

The last three lines look fine, assuming your JSON format is identical to that in the challenge.

What have you stored in your variable jsonData? Is that in the form of a String?

Steve.

Steve Hunter
Steve Hunter
57,712 Points
Steve Hunter
Steve Hunter
57,712 Points

Ah, right; you're inside the challenge trying to use your variable, books rather than the provided jsonData. I get you now!

Right, the JSONObject constructor takes a string. You have passed it a JSONObject. The conversion has already taken place. So, passing jsonData into the constructor, new JSONObject(jsonData); will fail as you can't cast from one type to the other.

Essentially, you don't need the constructor. If you wanted to use your object books just assign jsonData to it:

JSONObject books = jsonData;

But that's pretty pointless, really.

I hope that helps.

Steve.

CD Lim
CD Lim
4,782 Points
CD Lim
CD Lim
4,782 Points

Thanks !!! A lot !!!