Develop Reference

Scrolling ImageView along with Recylcer View

So,
I have a layout.xml file which contains a Recycler View. Now, what I want is, I added two image Views on top of this Recycler View but I want those ImageViews to scroll with the RecyclerView as well.
I just wanted to ask, is this possible to do? And if yes, how can I achieve this?
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/content_parent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<include
android:id="#+id/header_bar"
layout="#layout/section_header" />
<ImageView-1>
<ImageView-2>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/category_grid"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:paddingHorizontal="#dimen/category_grid_edge_space"
android:paddingTop="#dimen/category_grid_padding_top"
android:scrollbarSize="#dimen/grid_padding"
android:scrollbarStyle="outsideOverlay"
android:scrollbarThumbVertical="?android:attr/textColorSecondary"
android:scrollbars="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Put your RecycleView in NestedScrollView
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<include
layout="#layout/your_header"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/category_grid"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
also don't forget to disabled NestedScrolling for RecyclerView
myRecyclerView.setNestedScrollingEnabled(false);
OR
Add those views as a header. Here is a good guide on how to add a custom item view: https://medium.com/androiddevelopers/get-ahead-using-headers-in-recyclerview-2909a69b19

https://github.com/masudias/RecyclerView-with-Header-and-Footer
You can use header and footer i

Kotlin - Keep button sticky in AppBarLayout$ScrollingViewBehavior (in FragmentContainerView)

I have an issue with FragmentContainerView, it looks like this:
<androidx.fragment.app.FragmentContainerView
android:id="#+id/myFragment"
android:name="com.me.MyFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
And in its fragment, I have a recycler view, and a button:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:id="#+id/swipeRefreshLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"/>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
<Button
android:id="#+id/myBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerInParent="true"
android:gravity="bottom|center" />
However, when I am scrolling, button is also moving up, even though I set up alignParentBottom. I believe the issue is in this line of code:
app:layout_behavior="#string/appbar_scrolling_view_behavior"
which is actually:
<string name="appbar_scrolling_view_behavior" translatable="false">com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior</string>
FragmentContainerView is used in CoordinatorLayout. Note that button is out of SwipeRefreshLayout, so it shouldn't be affected by scrolling the recycler view.
I want to keep it sticky, so it doesn't move when I scroll the screen.
Any ideas?

Recyclerview in fragment which is inside nestedscrollview scrolling issue

In activity, I have TabLayout & FrameLayout for loading fragment. fragment contains RecyclerView. it works fine for first time only. but when I change tab and back to previous tab the RecyclerView not scrolling full.
Main Activity
<android.support.v4.widget.NestedScrollView
android:fillViewport="true"
android:layout_height="match_parent"
android:layout_width="match_parent">
<LinearLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="#+id/tabMain"
android:layout_height="wrap_content"
android:layout_width="match_parent" />
<FrameLayout
android:id="#+id/containerMain"
android:layout_height="match_parent"
android:layout_width="match_parent" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
Fragment
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/rvMedia"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:nestedScrollingEnabled="false" />
</LinearLayout>

The recyclerView has a smooth scrolling by itself but when we need to put recyclerView within any scrollView it will not work like the below:
Layout XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
</LinearLayout>
The solution for this is we need to used nestedScrollView instead of scrollview like the below
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.NestedScrollView
android:id="#+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</LinearLayout>
The problem occurs when we use nestedScrollView and put recyclerView inside nestedScrollView is, it scrolls in various speed depending on gesture. The scrolling feature will not be smooth.
So to fix this issue all you have to do after setting your adapter is to add this line ViewCompat.setNestedScrollingEnabled(recyclerView, false);
This is not a good solution. Placing a RecyclerView inside a NestedScrollView, causes ALL elements of the RecyclerView’s adapter to be rendered, ths using alot of memory. This can be so slow in most devices with less memory.
This approach might also lead to disabling need scrolling, which will disable views recycling thus all items will be initialized at once.e.g. In a list with 1000 items. This will make the application lag. You can avoid it if you use pagination where you load a fixed number of items when the user scrolls down on the list.
Read more about pagination.
Pagination with RecyclerView – Etienne Lawlor – Medium
Android RecyclerView Pagination with Paging Library using MVVM ...
Paging library overview | Android Developers

NestedScrollView smooth scroll to the top and to a view inside

First I need to scroll my NestedScrollView to the top, but smoothScrollTo(0, 0) doesn't work for me (page just jumping a bit). Second I wonder how can I scroll to a certain view inside my NestedScrollView. API 27, Support 27.0.2.
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<data/>
<android.support.v4.widget.SwipeRefreshLayout
android:id="#+id/refresh"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/PageBackground"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:descendantFocusability="blocksDescendants"
android:orientation="vertical"
android:paddingBottom="#dimen/indent_page_bottom">
...
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.v4.widget.SwipeRefreshLayout>
</layout>

Try using fling to achieve smooth scrolling :
nestedScrollView.fling(0);
nestedScrollView.smoothScrollTo(0, 0);

I had a nestedscrollviewand inside it there is recyclerview. I tried smoothScrollTo(0, nsv_main.top). Didn't work. I gave an id to nestedscrollview like below
<android.support.v4.widget.NestedScrollView
android:id="#+id/nsv_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/PageBackground"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:descendantFocusability="blocksDescendants"
android:orientation="vertical"
android:paddingBottom="#dimen/indent_page_bottom">
...
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
and gave nsv_main.scrollY = 0 in my click event. It worked, even though its not a smooth scroll.

How to design complex UI in android

How can I have a ViewPager above a RecyclerView, or have several RecyclerViews in a ScrollView? I designed the following layout, but it has some problems when scrolling.
What is the problem and how can I solve it?
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#dcdcdc"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".ActivityMain"
tools:showIn="#layout/app_bar_main">
<LinearLayout
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="200dip"
/>
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
</ScrollView>
I have tried compile 'com.bartoszlipinski:recyclerviewheader2:2.0.1' with
<com.bartoszlipinski.recyclerviewheader2.RecyclerViewHeader
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|top">
1- firstly it supports 11 sdk or greater,
2- secondly ViewPager wont work in header RecyclerView.
and i have tried RecyclerView layout_width="wrap_content" but it is just supported in sdk21 .
How can I solve the RecyclerView scrolling ?

Try losing the top ScrollView and using a ListView instead of RecyclerView.
ScrollView is unnecessary here and you need a hack for ViewPager to work with RecyclerView as it consumes all touch events. It would be simpler if you could get away with a ListView.

You can take your view pager to app bar in collapssing toolbar layout and it will be ok