I have a vertical recyclerview (with a GridLayoutManager) inside another recyclerview (with LinearLayoutManager). The problem I am facing right now is that, the inner recyclerview (with GridLayoutManager) binds all of it's items at the same time, even the views that are not on the screen at the moment (onBindViewHolder() gets called for all of its items).
To give you more information, in my layout file, I put height of my recycler view as wrap_content.
I think the problem is, since there are 2 nested vertically recyclerviews, when the parent RV wants to measure its children and the children is another RV, in onMeasure() it computes the size needed for the entire RV, not just the portion that it wants to bind on the screen.
Any idea how to solve this?
Here is the layout file for my outer recyclerview:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/component_list"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
And here is the code for my inner recyclerview:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/container"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/gutter"
android:paddingBottom="#dimen/gutter">
<TextView
android:id="#+id/title_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="#dimen/gutter"
android:textSize="30sp"
android:textColor="#android:color/white"
android:fontFamily="sans-serif-thin"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/my_slider"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
P.S.: I'm using this adapter delegate for my outer recyclerview:
https://github.com/sockeqwe/AdapterDelegates
I think nested recyclerviews are a very bad idea. When i try to scroll, which recyclerview has to respond the the scolling, the parrent or child.
That is why I think you are looking for the ExpandableListView? That's limited to only two levels of listings, but that sounds like it would work for your needs). It also solves the soling issue.
It would look something like this:
EDIT: even nested ExpandableListViews are possible:
EDIT: check this lib for horizontal scroling
This is a known bug.
You should not put a RecyclerView inside another RecyclerView because RecyclerView gives its children infinite space. Hence the inner RecyclerView keeps measuring till the dataset is exhausted. Try setting setAutoMeasureEnabled(false) to false on layout manager or you can solve this problem by using a wrapper adapter instead of inner recycler view.
The first thing you need to know is that, when you nest scrolling layouts, the inner ones will get infinity allowed height, effectively making them wrap_content. There is in fact a relatively easy way to fix this problem.
Say I had two nested RecyclerViews such as these, in this case vertically oriented.
<RecyclerView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical>
<View .../>
<!-- other stuff -->
<RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"/>
</RecyclerView>
The inner recyclerView here will bind all of it's children immediately every time because, from it's position, your screen will have infinite height.
The solution is to set the height of your inner recyclerview to some static value, not wrap_content or match parent, as either of those will simply fill up the outer recyclerview with one view that will all be bound at once due to it's large height. If you make the height of the inner recyclerview the same as the display's height, you should see your problem go away.
Here is an implementation that will not bind all children at once:
<RecyclerView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical>
<View .../>
<!-- other stuff -->
<RecyclerView
android:layout_width="match_parent"
android:layout_height="#dimen/screen_height"
android:orientation="vertical"/>
</RecyclerView>
Note the layout_height of the inner RecyclerView is now a fixed value pulled from the dimensions file. You yourself will have to come up with a reasonable value to put there.
Side Note: In order to make all of this work and for scrolling to work properly, you may have to play around with the parameter: NestedScrollingEnabled in your RecyclerViews - there are several known bugs relating to this that you may need to work around.
i.e.: innerRecyclerView.setHasFixedSize(true); and innerRecyclerView.setNestedScrollingEnabled(false).
so what happens here when you place a scrollview(no fixed size because of wrap content) inside another scrollview(again no fixed size because of wrap content),both nested scroll view fails to render.
So there is two solutions--
1- Either you will have to think of alternative solution for nested scrollviews
2- You can give outside recyclerview cell fixed height so that inside recycler view can get some fixed layout to render itself.
I could solve my issue by using only one Recyclerview, where it has a grid layout, and based on the component items i'm adding into it, i change the spancount for that. Basically instead of adding the inner recyclerview, i add the items that were supposed to go to the inner recyclerview, to the outer recyclerview.
Related
I am trying to create a scroll-able area which will contain various sections of the following types:
Horizontal Recycling Section
Vertical Recycling Section
Text Section
The approach I am taking is to have a NestedRecyclerView as the parent scroll view for all the child sections. This view looks like so:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/mynav_appbarLayout"
android:background="?attr/themeToolbarBg"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<include
android:id="#+id/mynav_toolbar"
layout="#layout/actionbar_toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.google.android.material.appbar.AppBarLayout>
<androidx.core.widget.NestedScrollView
android:id="#+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
<LinearLayout
android:id="#+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"/>
</androidx.core.widget.NestedScrollView>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
</layout>
Then, for each section type I am creating a corresponding view binding and adding it as a child to the LinearLayout which is inside the NestedScrollView.
There are 2 types of section layout, one which is a simple TextView (which I will omit here as it is not relevant) the other of which is a view which contains a RecyclerView. The layout manager for this RecyclerView is created dynamically depending on whether the section it is to be used for is a horizontal or vertical section.
The layout with the RecyclerView in looks like so:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:id="#+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:focusable="true"
android:focusableInTouchMode="true">
<TextView
android:id="#+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="24dp"
android:layout_marginTop="8dp"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/fooBarsRecycler"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:nestedScrollingEnabled="false"
app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior"/>
</LinearLayout>
</layout>
Now, when I am adding these views to the parent NestedScrollView's LinearLayout and setting up the LayoutManager for the associated RecyclerView to orientation Horizontal it works fine, but, when I use orientation Vertical (which is the same orientation as the NestedScrollView) the RecyclerView is NOT recycling views. Obviously this is leading to unacceptable performance.
After doing about a days worth of research and banging my head against the wall it appears that having a RecyclerView nested within a NestedScrollView with the same orientation as the NestedScrollView causes the RecyclerView to lose it's recycler functionality.
As you can hopefully see from the above layout, I have tried all the suggestions I could find, making sure the RecyclerView's height is not wrap_content, using layout_behaviour, setting the NestedRecyclerView to fill view port and so on.
I have exhausted 6 pages of google search around this issue and have tried every suggestion I have found either on SO or blogs and nothing is working.
Oddly, if I swap out the NestedScrollView for a ScrollView, the vertical RecyclerView regains it's recycler functionality, but now scrolls independently of the parent ScrollView which doesn't meet our requirements.
Is this a solved problem or do I need to rethink my entire solution? I.e. am I just missing an attribute or doing something wrong in the XML or is it fundamentally an issue with using a RecyclerView inside a NestedScrollView with the same orientation?
Here is the list of resources, the suggestions of which I have tried exhaustively to no avail:
How to use RecyclerView inside NestedScrollView?
How to use RecyclerView inside NestedScrollView
Recycler view inside NestedScrollView causes scroll to start in the middle
https://android.jlelse.eu/recyclerview-within-nestedscrollview-scrolling-issue-3180b5ad2542
https://medium.com/#mujtahidah/load-more-recyclerview-inside-nested-scroll-view-and-coordinator-layout-4f179dc01fd
https://github.com/google/flexbox-layout/issues/400
https://www.reddit.com/r/androiddev/comments/8oj8cb/having_recyclerview_inside_a_nestedscrollview_is/
https://github.com/mikepenz/FastAdapter/issues/447
https://www.reddit.com/r/androiddev/comments/bixl6r/nestedscrollview_recyclerview/
View Recycling not happens with Multiple Recyclerview inside NestedScrollView
How to make RecyclerView do recycling inside NestedScrollView?
https://code-examples.net/en/q/1d90611
As per a suggestion in the comments, I could model this with a multi type adapter, which is something I have done before but for this particular problem I am not sure this approach will work.
I think the comment is suggesting I model it like so:
Where the adapter would adapt types:
Horizontal Section
Text Section
Card Section
But, the requirement is this:
So, as you can hopefully see, the RecyclerView will have a LinearLayoutManager with orientation Vertical, but, once we hit the cards, they have to be laid out in a grid fashion, which of course the LinearLayoutManager does not support. So, perhaps I can have the final section be another RecyclerView with a GridLayoutManager? But, I tried this last night and it didn't work, there were scrolling issues as the bottom most RecyclerView is scrolling vertically within the outermost RecyclerView which is also scrolling vertically.
I want to document the problems I ran into and the solution for the benefit of others, and find help with the key flaw in my solution.
I want a RecyclerView with an arbitrary number of rows in a layout with a number of other Views. The RecyclerView and other Views should be in a ScrollView that scrolls, but the RecyclerView itself should not scroll.
Since the number of rows in the RecyclerView is unknown, and I'm required to have other views immediately underneath the RecyclerView, I can't use a fixed height or match_parent.
I experienced some odd problems: when I would update the RecyclerView data (using an AsyncListDiffer) and the UI was supposed to update, the entire RecyclerView would jump above the view it was constrained underneath, straight to the top of the parent. This is not how a ConstraintLayout is supposed to behave.
Then I was able to stop that from happening, but Views underneath the RecyclerView would disappear--appearing once the RecyclerView data updated.
The solution:
Put the RecyclerView and other Views inside a ConstraintLayout inside a ScrollView (or NestedScrollView)
Set the RecyclerView to have a height of wrap_content (and adding app:layout_constrainedHeight="true" doesn't hurt)
Make sure the rows in the RecyclerView have a fixed height and do not have a height of wrap_content
This was helpful to me after banging my head against the wall and trying some proposed solutions that did not work: make RecyclerView's height to "wrap_content" in Constraint layout
This solution is pretty simple. The layout can be something like:
<ScrollView
android:id="#+id/scrollView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<!-- other Views -->
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/otherView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toTopOf="#+id/anotherView"
/>
<!-- other Views -->
</androidx.constraintlayout.widget.ConstraintLayout>
</ScrollView>
And then the layout for a row:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="?attr/listPreferredItemHeight">
<!-- other views -->
</androidx.constraintlayout.widget.ConstraintLayout>
Here's the problem: I'm not a fan of fixed-height rows. What if other content needs to go in there? What if the user changes their text size? I much prefer flexible layouts that can adapt in size. But if I do that, then the RecyclerView takes up a screen's worth of height inside the ScrollView, shoving all lower views off the bottom of the screen, no matter how few rows it contains.
The alternatives I can think of are to make all the other Views outside the RecyclerView become rows of the RecyclerView, or to avoid a RecyclerView altogether and programmatically add Views to a LinearLayout. These are much uglier approaches.
Is there a way to fix it so the rows of the RecyclerView can have a height of wrap_content?
When I'm scrolling down, the items above the RecyclerView does not scroll unless I start touching from the layout above, and it only scrolls down when I have reached the end of the RecyclerView.
<NestedScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout>
<Some other items.../>
</LinearLayout>
<RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</NestedScrollView>
Note:
I actually use a fixed size for the RecyclerView, setting it via the code below:
float height_recyclerview = (ScreenUtil.getHeight(context) - (height_banner + height_bottom_navigation + height_create_post));
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, (int) height_recyclerview);
rv.setLayoutParams(layoutParams);
Why do I use fixed size if it works smoothly with wrap_content?
I will be displaying possibly thousands of items that may have
images, which will hurt performance if it does not actually do
recycling because of the issue that the RecyclerView is inside the
NestedScrollView
I have implemented an EndlessRecyclerViewScrollListener which has an
issue that it keeps loading more data from server continuously if
implemented with a RecyclerView that is within whatever scrollable
view, or if it is in a scrollable view, but does not have a fixed
height, even if you are not scrolling down.
I have tried the following:
set nested scrolling to false on the recycler view
try using scroll view instead of nested scroll view
a bunch of other code related to layouts and scrolling behaviors that others suggested which didn't work for me because I'm implementing it in a much more complicated layout and the fact that I use EndlessRecyclerViewScrollListener
What I want to fix?
I want to make the page scroll like a single page, not as a separate scrollable view.
Note that my recycler view has a fixed height that takes the entire screen's space meaning that its height is actually fit assuming that the linear layout above is not visible anymore if the user has scrolled down.
The ideal scenario is to make the scrollview scroll down first, to make the recycler view take the entire screen, so that the recyclerview will scroll however the user wants to.
Then the linearlayout above which should not be visible anymore if the recycler view has taken up all the space of the screen, should only show up if the recycler view has reached the top/first item, if the user keeps scrolling back up.
Read this.
Add app:layout_behavior="#string/appbar_scrolling_view_behavior" to your recycler xml.
<android.support.v7.widget.RecyclerView
android:id="#+id/conversation"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
NestedScrollView Smooth Scrolling
recyclerView.isNestedScrollingEnabled = true
Do this programmatically
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="0dp"
android:fillViewport="true"
...
I have two RecyclerViews placed vertically in a LinearLayout. I need to make both of them scrollable and that is why I have put the LinearLayout inside NestedScrollView
This is the my layout file.
<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
android:scrollbars="none">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/featured_list"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v7.widget.RecyclerView
android:id="#+id/all_topic_list"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
Also, I am disabling nested scrolling in Java code.
disableNestedScrolling(findViewById(R.id.all_topic_list));
disableNestedScrolling(findViewById(R.id.featured_list));
My RecylerView library version is 26.1.0
This works fine perfectly, but then onBindViewHolder method is getting called for all the items in the list. Ideally it should only be called for the visible items in the list.
I think the issue is happening because I am giving wrap_content to the RecyclerView. A lot of answers on this question suggest that the issue is solved in v23.2.1, but I am already using v26.1.0. How to solve this issue?
I had exactly the same problem. RecyclerViews are not meant to be placed inside scroll containers with the same scroll direction. The view recycling only works when the height is set to MATCH_PARENT.
Depending on the complexity of the content inside of the NestedScrollView and the anticipated amount of RecyclerView items:
Ignore the problem. If there are only a few simple items, you may
not need view recycling at all.
When I hit the problem, I analysed the layouts of other popular apps: For example, WhatsApp only uses RecyclerViews (or ListViews with view recycling) in some parts of their app.
Particularly, this group settings screen with hundreds of possible items is made of multiple ListViews wrapped by a ScrollView, without any view recycling.
Replace the NestedScrollView with a single
ReyclerView with multiple item types and put all of your scrollable content inside of it. This is the way to go if you need view recycling.
Beware that you also have to convert all the other content in the NestedScrollView (headers and footers, spacing) to RecyclerView items with their own ViewHolders.
If the setup is rather simple, I would recommend you to implement it without additional libraries, following the link above.
There are a few different libraries available to solve your problem (all of them follow the second approach with a single RecyclerView), but most come with a lot of extra features which you may not need:
RendererRecyclerViewAdapter
It comes with a ViewRenderer/ViewModel interface, which works like a
"partial" RecyclerView for a single item type. You would create one
for every item type and then register them in a single adapter.
Epoxy
A library/framework create by airbnb and used heavily in their app.
They have a lot of scrollable content (similar to a web page) with a
lot of different item types. Epoxy also helps with the composition of
the different items on a page, and it handles animations when the
content or its order changes. Too much if you only need it for a single screen.
Litho
A complete UI framework created by Facebook which comes with it's own rendering engine, a replacement for xml layouts and much more. As far as I understand, it allows you to do to handle large amounts of items (like the Facebook timeline) and the view recycling is handled automatically. Like Epoxy, you would only use this if your app includes things like endless scrolling with a lot of different item types and you really need the performance.
I tried Epoxy and RendererRecyclerViewAdapter, but after all I created my own multiple item type adapter. It can be created in less than 100 lines of code.
Starting from RecyclerView:1.2.0-alpha04 we can use ConcatAdapter to solve this problem
https://developer.android.com/reference/androidx/recyclerview/widget/ConcatAdapter
I tried your problem by adding 20 items in each recyclerview, with NestedScrollView application called onBindViewHolder method 40 times. As you disabling nested scrolling in Java code i suggest to use Scrollview. By using ScrollView application called onBindViewHolder 33 times.
If you fix your recyclerView's height to specific size instead of "match-parent" it will reduce call to onBindViewHolder greatly.
<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:fillViewport="false">
<android.support.v7.widget.LinearLayoutCompat
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.vishal.my2.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="#+id/featured_list"
android:layout_width="match_parent"
android:layout_height="300dp" />
<android.support.v7.widget.RecyclerView
android:id="#+id/all_topic_list"
android:layout_width="match_parent"
android:layout_height="300dp" />
</android.support.v7.widget.LinearLayoutCompat>
</ScrollView>
If Specifying hardcoded value to recyclerView's height does not meet your application requirement then you can try using ListView instead of recyclerView. pardon me if i am wrong, This was my first time answering any question.
Add this to nested scroll view android:fillViewport="false"
Over the past few weeks I've been learning to use the RecyclerView. I need to implement a horizontal list, ie, that by turning the device in landscape mode like so:
I found the best solution for this (how to create the horizontal displacement of RecyclerView, here), but encountered another problem. The item RecyclerView was larger than the height of the device (in landscape, horizontal), so I need to create a vertical and horizontal displacement, simultaneously.
I looked at the Android Developer methods for the LayoutManager class, but my skills are not high enough to understand most of the methods. I also tried putting a RecyclerView vertically inside another RecyclerView horizontally with all the content, but I get error:
IllegalStateException: RecyclerView has no LayoutManager
To rememedy this I removed all <View ... /> elements from the XML file, but this does not give any results.
To clarify what I am asking: is it possible to have my layout scroll both horizontally and vertically, and if you could explain how I would appreciate it.
I was so angry about all the problems that had tended with the application that had not thought about the easiest solution.
In a RecyclerView consists of two XML files, the main one where the RecyclerView is declared and another with content.
The simplest solution was to introduce the RecyclerView within a ScrollView. So I can move all items at a time thanks to ScrollView vertically and horizontally I can move the items thanks to RecyclerView in landscape mode.
activity_main.xml
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="#dimen/cardIn_margin_ext">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbarStyle="outsideInset"
android:scrollbars="horizontal" />
</ScrollView>
The accepted answer did'nt work for me. I had to use the HorizontalScrollView instead of simple ScrollView.
<HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="#dimen/cardIn_margin_ext">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbarStyle="outsideInset"
android:scrollbars="horizontal" />
</HorizontalScrollView >