Handling BottomNavigationView Active Menu Indicator with Jetpack Navigation

Описание: Learn how to properly manage the active menu indicator of `BottomNavigationView` when using Jetpack Navigation in Android, ensuring a seamless user experience.
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This video is based on the question https://stackoverflow.com/q/69900915/ asked by the user 'Bernhard Josephus' ( https://stackoverflow.com/u/11488790/ ) and on the answer https://stackoverflow.com/a/69902745/ provided by the user 'Zain' ( https://stackoverflow.com/u/9851608/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Solving the Active Menu Indicator Problem in BottomNavigationView with Jetpack Navigation

In the world of Android development, proper navigation management is essential for a smooth user experience. One common challenge arises when using BottomNavigationView alongside Jetpack Navigation. Developers often encounter a situation where the active menu indicator does not reflect the expected state after navigating between fragments. In this guide, we will explore how to ensure that the active menu indicator behaves as intended, particularly when navigating from one fragment to another and back.

The Problem

Consider a scenario where you have a BottomNavigationView containing four fragments: Fragment A, Fragment B, Fragment C, and Fragment D. Additionally, you may have another fragment, Fragment A1, which is not part of the bottom navigation menu.

When navigating in the following manner:

From Fragment A to Fragment A1

From Fragment A1 to Fragment B

You might expect that pressing the back button would take you back to Fragment A1 and highlight Fragment A as the active menu indicator. However, you notice that instead, Fragment B remains highlighted, which is not the desired behavior.

Solution Overview

To resolve this issue, we need to implement a mechanism that checks the previous fragment in the back stack before executing the back navigation behavior. Here’s a step-by-step breakdown of how we can achieve this.

Step 1: Understand the Navigation Flow

The expected navigation sequence is:

Navigate to Fragment A (A highlighted)

Go to Fragment A1 (A highlighted)

Move to Fragment B (B highlighted)

Press the back button to return to Fragment A1 (A highlighted again)

Step 2: Handling Back Navigation

We will add a custom back navigation handler in Fragment B to check what the previous fragment is and adjust the behavior accordingly.

Pseudo Code

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

Implementation

Here’s how the implementation looks in Kotlin:

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

Step 3: Highlighting the Correct Menu Item

To ensure that Fragment A becomes highlighted when returning from Fragment A1, we will manually set the menu item in BottomNavigationView to be checked.

Highlight Function

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

Incorporating into Back Navigation

Now, invoke the highlight function in the back button callback of Fragment B:

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

Side Note

This approach works well for the current navigation graph setup. To maintain a clean structure, consider using a separate graph or implementing nested navigation to keep Fragment A1 decoupled from the main navigation of your application.

Conclusion

By implementing these steps, you can manage the active menu indicator of BottomNavigationView effectively when navigating between fragments with Jetpack Navigation. This ensures that your app provides a consistent and user-friendly experience as users navigate through different components of your application.

If you encounter similar issues, remember to examine the back stack and take control of the navigation flow explicitly. Happy coding!