Solving the NestedScrollView Flicker Issue in Android

Discover how to effectively prevent flickering when hiding/showing the Action Bar and Search Bar in a `NestedScrollView` on scroll changes in your Android applications.
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Tackling Flickering in NestedScrollView When Scrolling

If you’ve been developing applications using Android, you may have encountered the problem of flickering in a NestedScrollView when the user scrolls. This often occurs when you are trying to hide or show the Action Bar or other UI elements based on the scroll position. In this guide, we’ll explore why this happens and how to fix it effectively.

The Problem Explained

When a user scrolls through a NestedScrollView, the method setOnScrollChangeListener is triggered continuously. This means that the visibility of the Action Bar or Search Bar is being toggled rapidly, causing a flickering effect on the screen. The flashing or flickering can be distracting and may lead to a poor user experience.

Typical Scenario

Your application has a nested scroll view.

You want to hide the Action Bar when scrolling down, and show it again when scrolling up.

You notice that due to rapid visibility changes, the UI elements flicker.

A Solution to the Flickering Issue

To remedy this situation, you need to take a more controlled approach when hiding or showing the Action Bar and Search Bar. Here’s how you can optimize the scrolling behavior using coordinates in dp instead of px to determine when to show or hide your action elements.

Step 1: Converting Pixels to Density-independent Pixels

First, we'll define a function to convert pixel values to dp. This allows for more consistent behavior across different screen sizes and densities.

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Step 2: Setting Up the Scroll Change Listener

Next, you can use viewTreeObserver to observe changes in the scroll view. This approach will help you determine the scroll position and the visibility of UI elements accordingly.

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

Step 3: Utilizing CoordinatorLayout (Optional)

For those who want additional features like proper scrolling behavior, consider using CoordinatorLayout. This layout provides powerful features that can help manage scrolling interactions more effectively across all views.

Conclusion

In conclusion, the flickering of the Action Bar and Search Bar when scrolling in a NestedScrollView can be effectively managed by implementing a pixel-to-dp conversion method and using viewTreeObserver to monitor scroll changes. This ensures that the UI components only change their visibility when necessary, resulting in a smoother experience for users.

By following these methods, you enhance the overall readability and usability of your app, creating a more engaging interface for your users.

If you still face issues or have questions, feel free to reach out! Happy coding!