Flutter - How to read json object with two lists? - json

Question

I have a json like this:
{
"data": [
{
"id": "99412",
"type": "post_list_item",
"attributes": {
"message": "#:user/3 \n#:user/77 \n#:user/52 #:user/3921 #:user/267 #:user/5 \n\nWhich sector will outperform in 2023 ???",
"visibility": "public_visible",
"created_at": "2023-01-07T14:38:00.691+05:30",
"updated_at": "2023-01-07T14:38:00.779+05:30",
"meta_info": null,
"type": "Post",
"likes_count": 8,
"replies_count": 2,
"widgets_data": [],
"is_liked": false,
"is_bookmarked": false,
"is_deleted": false,
"share_count": null
},
"relationships": {
"user": {
"data": {
"id": "86806",
"type": "user"
}
},
"poll": {
"data": {
"id": "483",
"type": "poll"
}
},
"tagged_users": {
"data": [
{
"id": "3",
"type": "user"
},
{
"id": "5",
"type": "user"
},
{
"id": "52",
"type": "user"
},
{
"id": "77",
"type": "user"
},
{
"id": "267",
"type": "user"
},
{
"id": "3921",
"type": "user"
}
]
},
"tagged_companies": {
"data": []
},
"tagged_topics": {
"data": []
},
"tagged_instruments": {
"data": []
},
"stories": {
"data": []
},
"attachments": {
"data": []
},
"media_files": {
"data": []
}
}
},
{
"id": "99548",
"type": "post_list_item",
"attributes": {
"message": "𝐓𝐨𝐩 𝐧𝐞𝐰𝐬 𝐭𝐨𝐝𝐚𝐲🎌 \n\n📍SGX Nifty up by 132 pts indicating a strong open
today. FIIs sold Rs 29 Bn while DIIs bought Rs 10.8 Bn of stocks on Friday.\n\n📍India surpasses Japan to become world's 3rd largest auto market in 2022: SIAM report\n\n📍Dr Lal PathLabs, leader in North India, expands in West India. Subsidiary opens apex lab in Mumbai - all nearby samples to be tested here instead of Delhi (positive).\n\n📍IL&FS pays 5 PSU Banks 87% of their ₹1,500 crore dues. Canara, Union Bank, Central, Punjab & Sind Bank.\n\n📍EV scooter co. Ather Energy to achieve $1 billion in revenue in 2023 and turn profitable in few years. Beneficiary: Hero Motors\n\n📍Outstanding dues by power distributors (discoms) to producers (gencos) has nearly halved to Rs 62,681 cr in last 1 year. Benficiary: PFC, REC (but priced in).\n\n📍Solar panel manufacters boost production as costs fall for polysilicon and wafer (RM for solar cells). Positive for Sterling Wilson Renewables, Borosil Renewables.\n\n1/2",
"visibility": "public_visible",
"created_at": "2023-01-09T09:05:41.226+05:30",
"updated_at": "2023-01-09T09:05:41.277+05:30",
"meta_info": null,
"type": "Post",
"likes_count": 4,
"replies_count": 1,
"widgets_data": [],
"is_liked": false,
"is_bookmarked": false,
"is_deleted": false,
"share_count": null
},
"relationships": {
"user": {
"data": {
"id": "83681",
"type": "user"
}
},
"poll": {
"data": null
},
"tagged_users": {
"data": []
},
"tagged_companies": {
"data": []
},
"tagged_topics": {
"data": []
},
"tagged_instruments": {
"data": []
},
"stories": {
"data": []
},
"attachments": {
"data": []
},
"media_files": {
"data": []
}
}
}, ],
"included": [
{
"id": "86806",
"type": "user",
"attributes": {
"display_name": "Ravi Gupta",
"username": "ravigupta132",
"dp_thumbnail": "/rails/active_storage/representations/proxy/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBBZ2E4IiwiZXhwIjpudWxsLCJwdXIiOiJibG9iX2lkIn19--763b2ccc4372862bb99de6620aa9fe9661693603/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdCem9MWm05eWJXRjBTU0lJYW5CbkJqb0dSVlE2RkhKbGMybDZaVjkwYjE5c2FXMXBkRnNIYVFHQWFRR0EiLCJleHAiOm51bGwsInB1ciI6InZhcmlhdGlvbiJ9fQ==--7b4a499a9ad66d05dd5deec71f9adfd36a29feb5/image_cropper_1672468958147.jpg",
"market_view": "neutral"
},
"relationships": {}
},
{
"id": "483",
"type": "poll",
"attributes": {
"question": "#:user/3 \n#:user/77 \n#:user/52 #:user/3921 #:user/267 #:user/5 \n\nWhich sector will outperform in 2023 ???",
"options": [
"Metal",
"PSU banks",
"IT",
"Infrastructure"
],
"vote_count": 52,
"grouped_count": null,
"ends_at": "2023-01-14T14:38:01.760+05:30",
"my_vote": null,
"is_expired": false
},
"relationships": {
"base_post": {
"data": {
"id": "99412",
"type": "post"
}
}
}
}, ]
}
Basically, 2 lists in an object.
I am unable to deserialize this data. How do I de-serialize this data to get 2 lists? I need to get data based on a common id.
This is what I have currently (WIP):
Future<List<Datum>> getPostData() async {
try {
Response response = await _dio.get(url);
var jsonData = response.data;
//Map<String, dynamic> postMap = response.data;
final someMappedObjectList = <Datum>[];
for (var map in jsonData["data"]) {
Datum someObject = Datum(
id: map["id"],
type: map["type"],
attributes: map["attributes"],
relationships: map["relationships"]);
//final someObject = Datum.fromJson(map);
someMappedObjectList.add(someObject);
}
//List<dynamic> listDatum = postMap["data"].toList();
//List<Datum> listDatum = Datum.fromJson(jsonData["data"]) as List<Datum>;
return someMappedObjectList;
} //
catch (e) {
print(e);
return [];
}
}
Future<List> getPostIncluded() async {
try {
Response response = await _dio.get(url);
var jsonData = response.data;
Map<String, dynamic> postMap = response.data;
List<dynamic> listIncluded = postMap["included"].toList();
return listIncluded;
} //
catch (e) {
print(e);
return [];
}
}

Answer 1

Especially for something this complex, I strongly suggest using the json_serializable package. It will save you quite a bit of trouble in the long term.