Скачать или смотреть Resolving the BottomSheet Expansion Issue in Jetpack Compose

Learn how to manage `BottomSheetScaffold` effectively in Jetpack Compose when the sheet content is empty, preventing unwanted expansion and runtime exceptions.
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Dealing with Jetpack Compose's BottomSheet Expansion Issue

Introduction

Creating a user-friendly interface in your Android apps often requires handling various UI components, one of which is the BottomSheet. Jetpack Compose offers a convenient way to implement BottomSheets through the BottomSheetScaffold. However, developers might encounter issues, particularly when the content of the BottomSheet is empty. This guide addresses a specific problem: the BottomSheet being unintentionally expanded when no content is loaded. We will explore the underlying issue and present a solution to ensure a seamless user experience.

The Problem

When utilizing the BottomSheetScaffold, you might notice that if the bottomSheet() function returns no content—meaning it is empty—the BottomSheet still thinks it is expanded. This results in the Scrim (a UI overlay) being active, and clicking on it can lead to a runtime exception similar to:

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

This issue arises because the BottomSheetState class, which manages the state of the BottomSheet, requires an anchor for height calculations. An empty BottomSheet does not provide an anchor, resulting in those unexpected behaviors.

Solution Overview

To address this problem, we need to ensure that our BottomSheet has considerate default behavior, particularly when it is empty. Below is a structured approach to handling this situation effectively.

Step 1: Understanding BottomSheetScaffold

The BottomSheetScaffold is set up with several parameters, including:

sheetPeekHeight

scaffoldState

sheetBackgroundColor

and more.

Maintaining a solid structure is essential for a proper BottomSheet implementation.

Step 2: Providing Default Content

Rather than allowing the BottomSheet to remain empty, consider providing a default composable that shows a loading indicator or a message indicating no content is available. This ensures that the BottomSheet maintains its structural integrity. Here’s an example of how to set default content:

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

Step 3: Updating the Visibility Logic

Make sure to adjust the logic that controls the visibility of the Scrim. The Scrim should only be visible when there is valid content to anchor to. To do this, check if there is any actual content being returned before allowing the Scrim to be visible.

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

Conclusion

In Jetpack Compose, handling a BottomSheet that may potentially have empty content can be tricky. By incorporating default content and refining the visibility checks for the Scrim, we can improve the user experience and prevent critical runtime errors. Implementing these strategies ensures your BottomSheet behaves predictably and maintains a clean interface.

By following the outlined steps, you can confidently handle BottomSheet scenarios in your Jetpack Compose applications with ease.