Скачать или смотреть Resolving the firebase bool passes to null Bug in Flutter Apps

Discover how to fix the issue of `bool` values passing as null in Firebase Firestore when toggling states in a Flutter application.
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This video is based on the question https://stackoverflow.com/q/62386082/ asked by the user 'GOMES 0802' ( https://stackoverflow.com/u/12845179/ ) and on the answer https://stackoverflow.com/a/62395792/ provided by the user 'Emmanuel' ( https://stackoverflow.com/u/5495197/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the firebase bool passes to null Bug in Flutter Apps

As Flutter developers, we often encounter bugs that can be frustrating to diagnose and resolve. One such issue involves handling boolean values when interacting with Firebase’s Firestore. A common problem arises when toggling a boolean value between true and false, only to find that it inexplicably turns into null in the database. In this guide, we will explore this issue and guide you on how to solve it effectively.

Understanding the Bug

The core of the problem lies in the management of booleans within your app. Consider the following scenario: You have a Flutter app that toggles a boolean value when a button is pressed, and you intend to store this value in Firestore. Yet, upon updating the database, the value defaults to null instead of true or false.

Symptoms

The value is not being updated correctly in Firestore.

You might find the value is set to null instead of the expected boolean.

Initial Code Review

Here is the relevant snippet of code that demonstrates the toggling functionality:

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In this piece of code, the boolean variable selected should hold the true/false state and should be passed to Firestore. However, if selected is null, it would lead to the issue we see.

Step-by-step Solution

To address this problem effectively, we need to ensure that the selected variable is properly initialized and toggled. Follow these steps to rectify the issue:

Step 1: Initialize the Variable

Make sure that the selected variable has a default boolean value. This can help avoid null values when performing operations.

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Step 2: Set the Value Correctly

In the initState method, where setInitialValue is called, confirm that you are correctly loading the previous value of selected. Here's the modified method:

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Step 3: Ensure Toggling Logic

Add logic within your button's onPressed function to toggle selected appropriately. This will ensure that every time you click the button, it's set to the opposite of its current state.

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Conclusion

By ensuring that the selected variable is properly initialized and that you implement a toggle mechanism, you can successfully prevent null values from being sent to Firestore. Always remember to check that your booleans have values before updating your database.

With these adjustments, your Flutter app will work more effectively with Firebase Firestore without the confusion of null values. Happy coding!