How to Insert a Fixed Footer Outside of a Scroll View in Android's Constraint Layout

Описание: Learn how to implement a fixed footer above a scroll view in Android using Constraint Layout, without encountering the "ScrollView can host only one direct child" error.
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This video is based on the question https://stackoverflow.com/q/70205863/ asked by the user 'misterios' ( https://stackoverflow.com/u/15662614/ ) and on the answer https://stackoverflow.com/a/70209442/ provided by the user 'Nhân Khuất Văn' ( https://stackoverflow.com/u/4123990/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Insert a Fixed Footer Outside of a Scroll View in Android's Constraint Layout

When designing Android applications, a common requirement is to create a layout that includes a scrollable area coupled with a fixed footer at the bottom of the screen. However, you might encounter an error stating "ScrollView can host only one direct child" when you try to do this using Android's XML layout. In this guide, we’ll explore how to resolve this issue effectively.

Understanding the Problem

In Android, a ScrollView is designed to contain only one direct child view. Hence, if you attempt to add multiple children within a ScrollView, Android will throw an exception. This limitation can make it challenging to position a footer directly below the scrollable content.

To achieve a user interface with a scrollable content area and a fixed footer, a different approach is necessary.

Solution Breakdown

Step 1: Use Constraint Layout

By using a ConstraintLayout, we can position both the ScrollView and the footer independently. Here's how to structure your layout:

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

Step 2: Key Layout Components

Constraint Layout: Serves as the container for our scrollable area and the fixed footer.

ScrollView: Set to have a height of 0dp and constrained between the top of the parent layout and the footer. This allows it to occupy the available space while maintaining scrollable content.

LinearLayoutCompat: Inside the ScrollView, this layout can hold multiple views without restrictions.

TextView for Footer: Placed below the ScrollView, it serves as the fixed footer that will always be visible regardless of scrolling.

Advantages of This Approach

Flexibility: You can add multiple views (buttons, text, images, etc.) inside the LinearLayoutCompat.

User Experience: The footer remains fixed at the bottom, enhancing navigation and usability.

Conclusion

This adjustment in your Android layout allows you to maintain a clean, user-friendly interface that adheres to Android guidelines while avoiding common pitfalls with the ScrollView. By leveraging ConstraintLayout, you can effectively implement a fixed footer without running into layout exceptions.

Feel free to use the provided code and customize your footer and scrollable contents as per your application's needs. Happy coding!