如何在Dart / flutter中映射和显示嵌套的JSON？

Question

I am new in flutter/ dart and working in a web service powered flutter app. I am currently facing a problem in Mapping and displaying Nested JSON data.

The JSON which i need to deal is provided from my local php server JSON format, i have tried and is working with code:

BD: "Bangladesh"
BE: "Belgium"
BF: "Burkina Faso"
BG: "Bulgaria"

code:

  Map _countries = new Map();

  void _getData() async {
    var url = 'http://country.io/names.json';
    var response = await http.post(url);

    if (response.statusCode == 200) {
      setState(() => _countries = json.decode(response.body));
      debugPrint('Loaded ${_countries.length} data.');
    }
  }

Flutter widget to display data:

return Card(
       child: new Row(
              children: <Widget>[
                    Expanded(
                      child: new Text(
                        '${key} : ',
                        style: TextStyle(fontSize: 28.0),
                      ),
                    ),
                    Expanded(
                      child: new Text(_counties[key],
                          style: TextStyle(fontSize: 28.0)),
                    )
                  ],
        )
);

I have the server side php code working and is supplying the following json data on POST request

JSON data i want to map and display similarly as above:

{
    "Employee_id1": {
        "first_name": "Staff",
        "last_name": "EFGH",
        "contact": "1223234555",
        "designation": "des1",
        "department": "d1",
        "picture": "http://i.pravatar.cc/300"
    },
    "Employee_id2": {
        "first_name": "Staff",
        "last_name": "EFGH",
        "contact": "1223234555",
        "designation": "des1",
        "department": "d2",
        "picture": "http://i.pravatar.cc/300"
    },
}

Connection Post request code:

void _getData() async {
    var url = 'http://myIP/file.php';
    var response = await http.post(url, body: 
                                  {"staffprofiles":"showStaffs"});

    if (response.statusCode == 200) {
      setState(() => _staffs = json.decode(response.body));
      debugPrint('Loaded ${_staffs.length} staff profiles.');
    }
}

I want the to show the JSON as profile cards for many staff profiles (in card) i am getting from server in ListView Builder

Answer 1

After a few hit and trials i figured out that all i needed was a nested MAP in dart,

Map[key][subkey]

The following code solved my problem:

return Card(
       child: new Row(
              children: <Widget>[
                    Expanded(
                      child: new Text(
                        '${key} : ',
                        style: TextStyle(fontSize: 28.0),
                      ),
                    ),
                    Expanded(
                      child: new Text(_employees[key]["first_name"],
                          style: TextStyle(fontSize: 28.0)),
                    )
                  ],
        )
);