Achieving a Custom Bottom Navigation Bar in Flutter

Описание: Learn how to create a `dynamic bottom navigation bar` in your Flutter application with unique width styles, spacing adjustments, and changing colors based on selection!
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This video is based on the question https://stackoverflow.com/q/63789882/ asked by the user 'byhuang1998' ( https://stackoverflow.com/u/12396033/ ) and on the answer https://stackoverflow.com/a/63793626/ provided by the user 'Salim Murshed' ( https://stackoverflow.com/u/9202118/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Achieving a Custom Bottom Navigation Bar in Flutter

In mobile application development, having a well-structured navigation system is crucial. One common design element many apps utilize is the bottom navigation bar. It allows users to quickly access different sections of the app with just a tap. However, Flutter may pose some challenges when attempting to create a bottom navigation bar with specific design requirements. In this post, we will explore how to achieve a bottom navigation bar that meets unusual specifications, such as varying item widths and consistent item spacing.

Understanding the Challenge

The task at hand involves creating a bottom navigation bar with the following features:

Five Navigation Items: Each with specific widths of 154, 153, 154, 153, and 154 respectively. This unconventional sizing makes it difficult to use default navigation components.

Icon and Text Arrangement: Each item must feature an icon and corresponding text that maintains exact spacing, which isn't directly configurable in the default BottomNavigationBar widget.

Dynamic Visual Feedback: Common functionality where colors change for icons, text, and the background upon selection.

Proposed Solution

To implement this custom bottom navigation bar effectively, we will use a combination of Flutter's StatefulWidget and our layout logic, allowing us to manage the current index and render the appropriate screen. Below is a breakdown of the steps and code necessary to realize this functionality.

Step-by-Step Implementation

Creating the Stateful Widget: We begin by setting up a StatefulWidget class for our navigation bar.

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Managing Tabs: In the _navState, we will declare our tabIndex and the list of screens corresponding to each navigation item.

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Building the UI: Next comes the main build method where we create a MaterialApp, structure the Scaffold, and design the bottom navigation bar with our specified styles.

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Customizing Navigation Items: Finally, when building the BottomNavigationBar items, we will use Container to customize each item's width.

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Conclusion

With this approach, you now have a custom bottom navigation bar that meets your unique specifications while providing a seamless user experience. The application will render without unnecessary reloading of the navigation bar, mimicking the functionality users expect from mobile applications.

If you encounter similar UI challenges in Flutter, refer back to this guide as a solution template to craft a custom navigation experience tailored to your app's needs.