converting string to map in dart

55

votes

I wanted to convert a string to map.

String value = "{first_name : fname,last_name : lname,gender : male, location : { state : state, country : country, place : place} }"

into

Map = {
first_name : fname,
last_name : lname,
gender : male,
location = {
  state : state, 
  country : country, 
  place : place
 }
}

How do I convert the string into a map<String, dynamic> where the value consists of string, int, object, and boolean?

I wanted to save the string to a file and obtain the data from the file.

dartflutter

107

votes

That's not possible.

If you can change the string to valid JSON, you can use

import 'dart:convert';
...
Map valueMap = json.decode(value);
// or
Map valueMap = jsonDecode(value);

The string would need to look like

{"first_name" : "fname","last_name" : "lname","gender" : "male", "location" : { "state" : "state", "country" : "country", "place" : "place"} }

25

votes

You would have to change the way you create the string.

I guess you are creating the string with the yourMap.toString() method, but you should rather use json.encode(yourMap), which parses your map to valid JSON, which you can the read with the json.decode(yourString) method.

5

votes

create two objects

class User {
  final String firstName;
  final String lastName;
  final String gender;
  final location;

  User({
    this.firstName,
    this.lastName,
    this.gender,
    this.location,
  });

  User.fromJson(Map json)
      : firstName = json['firstName'],
        lastName = json['lastName'],
        gender = json['gender'],
        location = Location.fromJson(json['location']);
}

class Location {
  final String state;
  final String country;
  final String place;

  Location({
    this.state,
    this.country,
    this.place,
  });

  Location.fromJson(Map json)
      : state = json['state'],
        country = json['country'],
        place = json['place'];
}

then use it like this

var user = User.fromJson(value);
print(user.firstName);

or convert it to list like this

var user = User.fromJson(value).toList();

4

votes

Make a wrapper class for the location where you define the methods fromMap, toMap

2

votes

you can do like this ->

import 'dart:convert'; ...

if your data like this ** {'bus1':'100Tk','bus2':'150TK','bus3':'200TK'}

**;

then you can do like this ->

Map valueMap = json.decode(value);

// or

Map valueMap = jsonDecode(value);

or if like this ->var data = {'1':'100TK','2':'200TK','3':'300TK'};

var dataSp = data.split(',');
Map<String,String> mapData = Map();
dataSp.forEach((element) => mapData[element.split(':')[0]] = element.split(':')[1]);

Note: Map first value was Int that's why I did that.

converting string to map in dart

5 Answers