Decode json flutter - flutter

Question

I have this data format
message": [
{
"id": 15989,
"title": "xxx",
"body": "xxx",
"type": "abc",
"data_hash": "{\"id\":\"3098\",\"number\":1}",
}, .....]
If I write like this
print(message['data']['type']);
I can get abc, but if I write print(message['data']['data_hash']);, I get invalid arguments error. Why?
I want to get the number in data_hash.
This is the full code
_firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async {
print("===== onMessage ====");
try {
print(message['data']['data_hash']);
} catch (e) {
print(e.toString());
}
});

Answer 1

data_hash row is a json. So you need to decode that row for use.
final data_hash_map = jsonDecode(message['data']['data_hash']);
print(data_hash_map); // { "id": 3098, "number": 1 }
print(data_hash_map["number"]); // for number

Answer 2

Decode your json as below
Map<String, dynamic> jsonData = jsonDecode(message)

Answer 3

I recommend to create a class to predefine the object as followed:
class Message {
int id;
String title;
String body;
String type;
DataHash dataHash;
message({this.id, this.title, this.body, this.type, this.dataHash});
Message.fromJson(Map<String, dynamic> json) {
id = json['id'];
title = json['title'];
body = json['body'];
type = json['type'];
dataHash = json['data_hash'] != null
? new DataHash.fromJson(json['data_hash'])
: null;
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['title'] = this.title;
data['body'] = this.body;
data['type'] = this.type;
if (this.dataHash != null) {
data['data_hash'] = this.dataHash.toJson();
}
return data;
}
}
class DataHash {
String id;
String number;
DataHash({this.id, this.number});
DataHash.fromJson(Map<String, dynamic> json) {
id = json['id'];
number = json['number'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['number'] = this.number;
return data;
}
}
You can call Message.fromJson(data) to decode.
Messsage message = Message.fromJson(data);
print(message.dataHash.number);

Answer 4

I hope this will work correctly
class _HomeState extends State<Mytimeoff> {
List<Map> list = [];
Map leaveRoot ={};
void getList() async {
var data = await http
.get('https:your api link');
leaveRoot = Map.from(json.decode(data.body));
setState(() {
for (Map js in leaveRoot['leavetype']) {
list.add(js);
}
});
print(jsonData);
}
#override
void initState() {
super.initState();
getList();
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
}