Saving Data in Flutter [SUBSCRIBER]

Introduction

Flutter is a powerful framework for building cross-platform mobile applications. When developing an app, it is crucial to have the ability to save data and persist it for future use. In this article, we will explore the different methods available in Flutter for saving data.

Shared Preferences

Shared Preferences is a simple way to store key-value pairs persistently. It is commonly used for saving small amounts of data, such as user preferences and settings. Flutter provides a plugin called `shared_preferences` that makes it easy to work with Shared Preferences.

To save data using Shared Preferences, you first need to initialize an instance of SharedPreferences. You can then use the provided methods to save and retrieve data. For example, to save a string value, you can use the `setString` method:

„`
SharedPreferences prefs = await SharedPreferences.getInstance();
prefs.setString(‚myKey‘, ‚myValue‘);
„`

To retrieve the saved value, you can use the `getString` method:

„`
String value = prefs.getString(‚myKey‘);
„`

SQLite Database

If you need a more robust and structured way to save data, you can use a SQLite database in Flutter. SQLite is a self-contained, serverless, zero-configuration, transactional SQL database engine. It is widely used for mobile app development due to its efficiency and reliability.

Flutter provides a plugin called `sqflite` for working with SQLite databases. With this plugin, you can create tables, insert, update, delete, and query data.

To use SQLite in Flutter, you need to add the `sqflite` dependency to your `pubspec.yaml` file. After that, you can initialize a database and perform operations on it. Here’s an example of creating a table and inserting data:

„`dart
Database database = await openDatabase(
path.join(await getDatabasesPath(), ‚my_database.db‘),
version: 1,
onCreate: (db, version) {
db.execute(‚CREATE TABLE my_table (id INTEGER PRIMARY KEY, name TEXT)‘);
},
);

await database.insert(‚my_table‘, {’name‘: ‚John‘});
„`

You can also query the database to retrieve data:

„`dart
List<Map> rows = await database.query(‚my_table‘);
„`

File Storage

In some cases, you may need to save larger amounts of data, such as images or documents. For this purpose, Flutter provides access to the device’s file system. You can use the dart:io library to read from and write to files.

To save a file in Flutter, you first need to get the file path using the `path` package:

„`dart
String filePath = path.join(await getApplicationDocumentsDirectory(), ‚my_file.txt‘);
File file = File(filePath);
await file.writeAsString(‚Hello, World!‘);
„`

To read from the file:

„`dart
String contents = await file.readAsString();
„`

Conclusion

In conclusion, Flutter offers various methods for saving data depending on your needs. Whether it is Shared Preferences for simple key-value pairs, SQLite for more structured data, or file storage for larger files, Flutter provides the necessary tools and plugins to handle data persistence in your mobile applications. It is crucial to choose the right method based on the size and complexity of the data you need to store. Happy coding and happy data saving in Flutter!
source: https://www.kodeco.com/38305847-saving-data-in-flutter