Скачать или смотреть Implementing Flutter Login Control on Splash Screen

Learn how to check user login status on the splash screen in Flutter applications with a simple and effective method.
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This video is based on the question https://stackoverflow.com/q/67588393/ asked by the user 'Anastasia Selezneva' ( https://stackoverflow.com/u/15862777/ ) and on the answer https://stackoverflow.com/a/67588614/ provided by the user 'Nisanth Reddy' ( https://stackoverflow.com/u/10780861/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Easily Implementing Flutter Login Control on Splash Screen

Creating a login application can be a straightforward task, but it often comes with specific requirements. One of the typical functionality you might need is to verify whether a user is logged in when they open the app. This can provide a smoother user experience by redirecting them to the appropriate screen right from the splash screen. In this guide, we will dive into how to implement login control on a splash screen using Flutter.

The Problem at Hand

You are building a small login application and you want to check if the user has a token code when they enter the application. Based on their login status, you want to navigate either to the home screen or the login screen. This is a common scenario especially in applications requiring user authentication.

Understanding the Solution

To implement this, we will use Flutter's Future and async functionalities for asynchronous programming. Let's break this down into manageable sections.

1. Setting Up Your Main File

In your main.dart file, you set up the main application structure. At its core, you have a MyApp widget that initializes your application. Here's what that looks like:

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Here, we specify that SplashScreen is the home widget that will be displayed first.

2. Building the Splash Screen

Now, let's define how the SplashScreen works. The splash screen will call a function to check if the user is logged in and navigate to the appropriate screen based on the result.

Revised Code for SplashScreen

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Important Changes Implemented:

Awaiting the Future: The loginControl() function now correctly uses await to wait for isLoginUser() to resolve before making a routing decision. This is crucial because isLoginUser() returns a Future<bool>, meaning it executes asynchronously.

3. AuthController Setup

Now that we have our splash screen set up, we need to ensure the AuthController is correctly checking for the user token.

AuthController Code

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This class fetches the token from SharedPreferences. If the token exists, it returns true, indicating the user is logged in; otherwise, it returns false.

Conclusion

By implementing these changes, the application can effectively control user navigation right from the splash screen based on their login status. Properly using asynchronous programming with Future and await is critical in Flutter for tasks like user authentication where results are fetched over time.

Now, you're all set to enhance your Flutter application with a smart login management feature! Happy coding!