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Learn how to ensure that a local database exists in Flutter before navigating to your app's pages, thus improving user experience by directing them to the appropriate interface.
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This video is based on the question https://stackoverflow.com/q/62588201/ asked by the user 'Mrunal Joshi' ( https://stackoverflow.com/u/13454830/ ) and on the answer https://stackoverflow.com/a/62589323/ provided by the user 'EdwynZN' ( https://stackoverflow.com/u/3547212/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Check if a Local Database Exists in Flutter Before Displaying Any Page

When developing Flutter applications that rely on local databases, it's essential to ensure that the database exists before loading any pages. Not only does this prevent crashes, but it also helps provide a better user experience by redirecting users to the appropriate screen based on whether the database is present or not. In this post, we will break down the solution step-by-step to help you navigate this problem effectively.

The Problem

You have implemented a database helper class in your Flutter application that checks for the existence of a local database. However, the function checkDb() returns a Future, which means it does not return a boolean value directly but rather an asynchronous operation. Thus, it can be tricky to use its result in a synchronous context, especially when deciding the initial route for your application in the main.dart file.

Understanding the Solution

To resolve the issue of navigating to different pages based on the existence of the database, we need to await the checkDb() function so that we can get the boolean value it returns. Here are the steps to implement this correctly.

Step 1: Modify the main Function

Update your main function to correctly await the result from checkDb():

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

In this snippet:

We await the checkDb() method so we can use its boolean result.

Depending on whether the database exists, we assign the initial route to either the main page or the sign-in page.

Step 2: Ensure Path Consistency

Make sure that both your checkDb() and initdb() functions use the same path for the local database. If they differ, the existence check will fail. You can modify checkDb() as follows:

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

Step 3: Understanding Database Paths

To further clarify:

The function getDatabasesPath() is used to retrieve the default path for the database, which may differ by platform (Android vs. iOS).

The function getApplicationDocumentsDirectory() returns the application’s documents directory, frequently used for storing files but not necessarily the same as the database's path.

You have two options:

Use the same method for both checkDb() and initdb() to ensure consistency.

Decide which path method suits your application needs and stick to it.

Conclusion

By properly handling asynchronous operations in your Flutter application and ensuring that both database path checks point to the same location, you can confidently navigate users to the appropriate page based on the existence of a local database. Implementing this method not only enhances your app's stability but also improves user experience significantly.

If you follow the outlined steps in this guide, you should be able to efficiently check the status of your local database and navigate users accordingly. Happy coding!