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Learn how to effectively store your Flutter app's counter value using `shared_preferences` for persistent data.
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How to Store a Flutter Project's Counter App Last Value in Local Database

When developing a mobile application with Flutter, one common feature you might want to implement is storing the last value of a user interaction even after the app closes. For instance, if you're building a simple counter app, you would want to save the last incremented number to retrieve it later when the app is opened again. In this guide, we will explore how to achieve this by using the shared_preferences library in Flutter.

The Problem: Saving the Counter Value

Imagine you've built a default Flutter counter app that increments a value each time a floating action button is pressed. The challenge arises when you need the app to remember the last incremented number (e.g., 20) the next time the user opens the app. This is where the concept of local storage comes in handy. Luckily, Flutter provides built-in support for storing simple data with the help of the shared_preferences package.

Solution Overview

We will break down the solution into the following steps:

Setup the shared_preferences package.

Implement a Save Button to store the counter value.

Retrieve the counter value when the app starts.

Step 1: Setup the shared_preferences Package

First, we need to add the shared_preferences package to our Flutter project. This allows us to easily save and retrieve simple data types such as integers, strings, and booleans.

Open your pubspec.yaml file.

Add shared_preferences to the dependencies section, like so:

[[See Video to Reveal this Text or Code Snippet]]

Run flutter pub get to install the package.

Import the package in your Dart file:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Implement a Save Button to Store the Counter Value

Now that we have set up the package, we can create a button to save the current value of the counter. We will modify our existing button configuration to include a Save button.

Here’s how you can do this:

[[See Video to Reveal this Text or Code Snippet]]

This code snippet creates a button that triggers the saving of the counter value to local storage when pressed.

Step 3: Retrieve the Counter Value When the App Starts

Once we have the functionality to save the counter, we need to ensure that the last saved value is displayed when the app starts up. This can be achieved by using the initState() method in our widget.

Here is how you can implement it:

[[See Video to Reveal this Text or Code Snippet]]

In this code, we retrieve the stored counter value using prefs.getInt('counter'). If no value has been stored yet, it defaults to 0.

Conclusion

In this guide, we demonstrated how to store the last value of a counter in a Flutter app using the shared_preferences library. This simple method allows for seamless user experience by persisting user data across app launches. Implementing this feature is a small but impactful improvement that enhances the usability of your application.

Feel free to experiment with this approach and expand it into larger applications that require local data storage. Happy coding!