Flutter json decode returns null - json

Question

I'm getting a null return when I run the following code. Apparently I'm not accessing json correctly.
Is there another way to access json data? Or is it ok to use it like that?
Future Class - parsing json from a url
Future<List<User>> _getUsers() async {
var data = await http.get("https://...api.php");
if (data.statusCode == 200) {
print('Status Code 200: Ok!');
var jsonData = json.decode(data.body);
List<User> users = [];
for (var u in jsonData[0]) {
print(u[0]["title"]);
User user = User(u["id"], u["source"], u["desc"], u["link"], u["title"]);
users.add(user);
}
print(users.length);
return users;
} else {
throw Exception('Failed to load json');
}
}
Class
class User {
final int id;
final String source;
final String desc;
final String link;
final String title;
User(this.id, this.source, this.desc, this.link, this.title);
}
Basic json structure:
{
"0":{
"id":0,
"source":"XXX",
"link":"XXXX",
"title":"XXXX",
"desc":"XXXX"
},
"1":{
"id":1,
"source":"XXX",
"link":"XXXX",
"title":"XXXX",
"desc":"XXXX"
}
}
What am missing here? thanks.

Answer 1

You're trying to use something that isn't a list as a list. The json structure you've provided looks like part of an object and not a list.
A list would look like this:
[{
"id": 0,
"source": "XXX",
"link": "XXXX",
"title": "XXXX",
"desc": "XXXX"
}]
But since the underlying structure is a Map you could iterate over the keys, doing something like this:
for (var k in jsonData.keys) {
var u = jsonData[k];
print(u["title"]);
User user = User(u["id"], u["source"], u["desc"], u["link"], u["title"]);
}

Answer 2

Your json structure is not a real json. But if your json is like this:
{
"0":{
"id":0,
"source":"XXX",
"link":"XXXX",
"title":"XXXX",
"desc":"XXXX"
},
"1":{
"id":1,
"source":"XXX",
"link":"XXXX",
"title":"XXXX",
"desc":"XXXX"
}
}
You can get data like this:
for (int i = 0; i < length; i ++) {
User user = User(u["$i"]["id"], u["$i"]["source"], u["$i"]["desc"], u["$i"]["link"], u["$i"]["title"]);
users.add(user);
}