Flutter get Object property Name

Question

I passed the following object:

var myVar = { typeA: { option1: "one", option2: "two" } }

I want to be able to pull out the key typeA from the above structure.

This value can change each time so next time it could be typeB.

So I would like to know if there is any way to do that

Answer 1

I was able to solve using 'keys'

for a json example like this:

{
"1-0001": {
  "name": "red",
  "hex": "FF0000"
 },
"1-0002": {
  "name": "blue",
  "hex": "0000FF"
 },
"1-0003": {
  "name": "green",
  "hex": "008000"
 }
}

I was able to use

Map<String, dynamic> decoded = json.decode(jsonString);
for (var colour in decoded.keys) {
  print(colour);                   // prints 1-0001
  print(decoded[colour]['name']);  // prints red
  print(decoded[colour]['hex']);   // prints FF0000
}

Answer 2

To get all filenames you can use:

var data = ...
 
var filenames = [];
for(var i = 0; i < data.length; i++) {
  var item = data[0]['files'];
  var key = item.keys.first;
  var filename = item[key]['filename'];
  filenames.add(filename);
}

print(filenames);

Answer 3

You need to define a data type. It is basically a map of (key value-pair) where key is changed as stated in question typeA or typeB This Object has 2 properties option1 and option2 which is also strings.

Here is the sample code to construct model and how to use it

import 'package:TestDart/TestDart.dart' as TestDart;

main(List<String> arguments) {
  var  map = new Map<String, MyObject>();
  map['typeA'] = new MyObject("one", "two");
  map['typeB'] = new MyObject("one", "two");

  print(map['typeA'].toString());
  print(map['typeA'].toString());
}

class MyObject {
  String _option1;
  String _option2;

  MyObject(this._option1, this._option2);

  String get option2 => _option2;

  String get option1 => _option1;

  @override
  String toString() {
    return 'MyObject{option1: $_option1, option2: $_option2}';
  }


}

Relevant answer

 map.forEach((key, value) {
    print("Key : ${key} value ${value}");
  });