Android NestedScroll Layout can Mess with your CoordinatorLayout and RecyclerView

While working on two separate tasks recently, I ran into frustrating layout issues that were both caused by NestedScrollView. Here's what happened and how I fixed them.

The Collapsing Toolbar That Wouldn't Stay Put

During development of a product details screen, I needed a fixed, non-scrolling toolbar. The layout used CoordinatorLayout with CollapsingToolbarLayout, and despite explicitly setting scroll flags to disable movement, the toolbar kept collapsing. After hours of debugging and layout inspection, I and a colleague tracked down the culprit - a NestedScrollView in the content area was hijacking the scroll behavior.

What Fixed It

Removing NestedScrollView immediately solved the problem. The toolbar stayed fixed exactly as intended, and the content scrolled smoothly.

Disappearing EditText Fields in a Form

The second issue came up in a different app where I was building a form with dynamic fields in a RecyclerView. Everything looked fine until testing - the EditText fields would vanish when trying to enter text. The form was wrapped in a NestedScrollView for handling overflow content, which turned out to be the root cause.

The Fix

We removed the NestedScrollView wrapper entirely and let RecyclerView manage its own scrolling. Not only did this fix the EditText visibility, but it also improved the overall form performance.

Looking Back

Both issues wasted valuable development time until I identified NestedScrollView as the common denominator. While it's a powerful widget for complex scrolling, I've learned to be very cautious about using it. My takeaways:

1. Let RecyclerView handle its own content
2. Only reach for NestedScrollView when absolutely necessary

Keeping it simple has saved me from layout headaches in subsequent projects.