Flutter - How to parse JSON data?

Question

I want to parse my JSON data and display all the nodeValues of the rows and not just [7] (which contains the word hello), however my FutureBuilder doesn't display the JSON data (stuck on CircularProgressIndicator) even though i'm following the correct JSON path.

//Updated code
class Feed {
  String title;

  Feed({this.title});

  factory Feed.fromJson(Map<String, dynamic> json) {
    return Feed(
        title: json["data"]["tables"][0]["rows"][7]["cols"][1]["nodeValue"]);  
  }
}
//I am making a post method to an API that returns me a JSON output.
Future<List<Feed>> post() async {
  final Response<String> result =
      await Dio().get('https://example.com');
  String _baseUrl = "https://html2json.com/api/v1";
  var options = Options(
    contentType: "application/x-www-form-urlencoded; charset=UTF-8",
    followRedirects: false,
  );

  final response = json.decode(result.data);

  final responseJson = await Dio().post(
    _baseUrl,
    data: response,
    options: options,
  );

  if (responseJson.statusCode == 200) {
    return (response as List).map((json) => Feed.fromJson(json)).toList();
  } else {
    return null;
  }
}
  //This is stuck on CircularProgressIndicator();  
FutureBuilder(
              future: post(),
              builder: (context, AsyncSnapshot<List<Feed>> snap) {
                if (snap.hasData) {
                  return ListView.builder(
                      itemCount: snap.data.length,
                      itemBuilder: (BuildContext context, int index) {
                        return Text(snap.data[index].title);
                      });
                } else {
                  return CircularProgressIndicator();
                }
              });

Are you parsing it with the json constant available in Dart? api.flutter.dev/flutter/dart-convert/json-constant.html — J. S.
– J. S., Commented Oct 13, 2020 at 11:45
Seems like your post() returning list of Feed objects. So, try using Feed member snap.data[index].someVariable — Blasanka
– Blasanka, Commented Oct 13, 2020 at 11:46

Luiz Filipe Medeira · Accepted Answer · 2020-10-13 12:14:16Z

1

I changed a few things to make your code work with the json place holder. You were using response.statusCode == 200, but response has no status code, the status code is on the var link.

class Feed {
  String title;

  Feed({this.title});

  factory Feed.fromJson(Map<String, dynamic> json) {
    return Feed(title: json["title"]);
  }
}

Future<List> post() async {
  final Response<String> result = await Dio().get('https://jsonplaceholder.typicode.com/todos');
  final response = json.decode(result.data);
  if (result.statusCode == 200) {
    return (response as List)
        .map((json) => Feed.fromJson(json))
        .toList();
  } else {
    return null;
  }
}

return FutureBuilder(
       future: post(),
       builder: (context, AsyncSnapshot<List> snap) {
              if (snap.hasData) {
                      return ListView.builder(
                          itemCount: snap.data.length,
                          itemBuilder: (BuildContext context, int index) {
                            return Text(snap.data[index].title);
                          });
                    } else {
                      return CircularProgressIndicator();
                    }
                  });

answered Oct 13, 2020 at 12:14

Luiz Filipe Medeira

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6 Comments

Arnav Over a year ago

It didn't work, I updated my code, could you please check it out? @Luiz ?

Luiz Filipe Medeira Over a year ago

Can you debug the function? Is execution running up to Feed.fromJson?

Arnav Over a year ago

I am getting my response from the api, but the snapshot doesn't contain any data

Luiz Filipe Medeira Over a year ago

Your json has a "data" key ? in fromJson json["data"].

Arnav Over a year ago

Yes the response is within data and then tables

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