Learn Read and Write Properties File in Dart with Tutorials

This tutorial shows how to read and write properties files in Dart using the shared_preferences package.

shared_preferences is a dart and flutter package, used to parse and store key and value pairs, In Real time projects, you can use storage configuration and settings. It supports basic scalar types such as numbers, strings, and arrays of strings or numbers.

To use the shared_preferences package in the project, add dependency in pubspec.yaml

name: example
description: example to read
version: 0.0.1
environment:
  sdk: '>=2.0.8 <3.0.0'
dependencies:
   shared_preferences: ^2.0.8

Next, Install dependency using pub get command in the terminal. In Dart, You can use the below

dart pub get

In the Flutter project use below

flutter pub get

This example explains reading properties files and store key and value pairs in shared

It also writes the key and value pairs object to write the file.

Let’s define config.properties

host= localhost
port= 3306
dbname= employes
username= root
password= root

How to read properties in Dart

Following are steps to parse properties in Ruby.

import shared_preferences/shared_preferences.dart package using import keyword.
Create an instance using SharedPreferences.getInstance()
It provides below methods to read the values of a key
- getString() for string values
- getInt for numbers
- getBool() for boolean values
Next, Create a Map object with the given values
read-properties.dart:

import 'dart:async';

import 'package:shared_preferences/shared_preferences.dart';

Future<Map<String, dynamic>> readProperties() async {
  SharedPreferences map = await SharedPreferences.getInstance();

  String host = map.getString('host') ?? '';
  int port = map.getInt('port') ?? 0;
  String username = map.getString('username') ?? '';
  String dbname = map.getString('dbname') ?? '';

  String password = map.getString('password') ?? '';

  Map<String, dynamic> result = {
    'host': host,
    'port': port,
    'dbname': dbname,
    'username': username,
    'password': password,

  };

  return result;
}

// Example usage
void main() async {
  Map<String, dynamic> properties = await readProperties();
  print('Read Properties: $properties');
}

Running the ruby read-properties.dart in the terminal gives the following output

host=localhost
dbname= employee
port= 3306
username= root
password= root

Write Map object to properties file in Dart

Create and initialize a dictionary of key and value pairs
get SharedPreferences object
Set the values using setString, setInt, setBool methods

write-properties.dart:

Future<void> writeProperties(Map<String, dynamic> properties) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();

  // Replace with values
  prefs.setString('host', properties['host']);
  prefs.setInt('port', properties['port']);
  prefs.setString('dbname', properties['dbname']);
  prefs.setString('username', properties['username']);
  prefs.setString('password', properties['password']);

}

// Example for writing properties
void main() async {
  Map<String, dynamic> properties = {
      'host': `localhost`,
    'port': '3016',
    'dbname': 'students',
    'username': `root`,
    'password': `root`,
  };

  await writeProperties(properties);
}

Running the code dart write-properties.dart on the terminal creates properties and the output is

host=localhost
port=3016
dbname= students
username= root
password= root

sharedPreferences is used to write and read key and value pairs for configuration settings.

Properties File - Dart

How to read properties in Dart

Write Map object to properties file in Dart