Develop Reference

How to properly scroll nested-scrollview?

How to properly scroll to a position in nestedscrollview which is inside a coordinate layout? When I use scrollTo(), it seems like the view inside AppBarLayout is loosing the ability to scroll down when I scroll to the end of NestedScrollView and coming back to top. What I need to know is how to programtically scroll to a position in nestedscrollview without causing problem with the normal behavior of collapsing layout.
Issue is similar to what is mentioned in this post:
The Coordinator layout doesn't Scroll up for a specific position
There is a Gif attached along with the above question:
https://i.stack.imgur.com/uSGfX.gif
I have tried the solution in above link, but it is not working.

RecycleView inside BottomSheet overriding scroll property

I have one RecyclerView inside Bottom Sheet and I don't want recyclerview to be scrollable inside it. But here I am facing a problem that Bottom Sheet expand and Collapse swipe property interfere with Recyclerview scroll and nothing is happening when I swipe. Please help me to solve this issue.

Android: ScrollView vs NestedScrollView

What is the difference between ScrollView and NestedScrollView? Both of them, extend FrameLayout. I want to know in depth pros and cons of both of them.

NestedScrollView as the name suggests is used when there is a need for a scrolling view inside another scrolling view. Normally this would be difficult to accomplish since the system would be unable to decide which view to scroll.
This is where NestedScrollView comes in.

In addition to the nested scrolling NestedScrollView added one major functionality, which could even make it interesting outside of nested contexts: It has build in support for OnScrollChangeListener. Adding a OnScrollChangeListener to the original ScrollView below API 23 required subclassing ScrollView or messing around with the ViewTreeObserver of the ScrollView which often means even more work than subclassing. With NestedScrollView it can be done using the build-in setter.

Other than the advantages listed in the answers given, one more advantage of NestedScrollView over ScrollView is its compatibility with CoordinatorLayout. The ScrollView does not cooperate with the CoordinatorLayout. You have to use NestedScrollView to get "scroll off-screen" behaviour for the toolbar.
Toolbar will not collapse with Scrollview as child of CoordinatorLayout

NestedScrollView
NestedScrollView is just like ScrollView, but it supports acting as
both a nested scrolling parent and child on both new and old versions
of Android. Nested scrolling is enabled by default.
https://developer.android.com/reference/android/support/v4/widget/NestedScrollView.html
ScrollView
Layout container for a view hierarchy that can be scrolled by the
user, allowing it to be larger than the physical display. A
ScrollView is a FrameLayout, meaning you should place one child in it
containing the entire contents to scroll; this child may itself be a
layout manager with a complex hierarchy of objects
https://developer.android.com/reference/android/widget/ScrollView.html

NestedScrollView is just like ScrollView, but in NestedScrollView we can put other scrolling views as child of it, e.g. RecyclerView.
But if we put RecyclerView inside NestedScrollView, RecyclerView's smooth scrolling is disturbed. So to bring back smooth scrolling there's trick:
ViewCompat.setNestedScrollingEnabled(recyclerView, false);
put above line after setting adapter for recyclerView.

I think one Benefit of using Nested Scroll view is that the cooridinator layout
only listens for nested scroll events. So if for ex. you want the toolbar to scroll down when you scroll you content of activity, it will only scroll down when you are using nested scroll view in your layout. If you use a normal scroll view in your layout, the toolbar wont scroll when the user scrolls the content.

<androidx.core.widget.NestedScrollView android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
// your Layout xml code
</androidx.core.widget.NestedScrollView>

Toolbar not collapsing with nested RecyclerView

I made collapsible toolbar on Activity, but there is one problem.
Screen contains RecyclerView that has multiple layout items, and one of them is another RecyclerView that has horizontal scroll. When main recycler is scrolled, toolbar doesn't expand or collapse when scroll started on that nested recycler, but on other views it's working as it should.
To make it easier to understand: when I first touch screen on position where there is nested RecyclerView and try to scroll up and down, there is no collapsing or expanding of toolbar.
Any idea what might be causing that issue and how to fix it?

I only needed to set recyclerView.setNestedScrollingEnabled(false) for the nested RecyclerView to work.
Thanks to Reddit user in this thread:
Toolbar not collapsing with nested RecyclerView

For those who would like the same thing in Kotlin is:
recyclerView.isNestedScrollingEnabled = false
And for XML it is this property in RecyclerView but only for API 21 and higher:
android:nestedScrollingEnabled="false"

Android Design Lib CollapsingToolbarLayout stops interact when horizontal RecyclerView is touched

I have an activity with CollapsingToolbarLayout for parallax effect(From Android Design Library) and FrameLayout where i set Fragment.
Fragments layout contains NestedScrollView.
Everything is working well except one moment. In NestedScrollView I have a horizontal RecyclerView with StaggerGridLayoutManager and when i scroll vertically from that recyclerview - parallax not starting. When i scroll from any other place of screen it works.
Seems it's problem with layout_behavior tag or loosing focus of NestedScrollView.
Does any one faced this problem ? Some ideas ?

Fuh! Got a solution! Disabling nested scroll on RecyclerView solved the problem.
recyclerView.setNestedScrollingEnabled(false);