Scenario - I am working on an app that shows events respective to particular dates in a viewpager, where each page represents a day(i.e 24 hrs in a vertical manner, similar to google calendar). Each page/fragment contains a vertical scrollview(it has a framelayout inside it) and based on list of events i am dynamically creating custom-views(view position and dimension is based on the corresponding event timing and duration) and adding it to the scrollview. User can drag and drop events between dates.
Issue - I have successfully achieved the view creation part, now the issue is with performance. Sometimes vewpager(using FragmentStatePagerAdapter) lags while swiping through pages.
Someone please suggest me how to reduce the lag or any better ways to achieve this
Yes I had a similar performance with viewpager and FragmentStatePagerAdapter, the problem with viewpager is that pre creates the views either side of the current view to speed up the swipe to next view.
This works well for static views but for views with dynamic data the pre-created view was usually out of date and needed to be regenerated when the user swiped to it.
Thus it was having to call onCreateView on 3 views while the user swiped between views leading to lag sometimes.
I thought of 2 improvements for performance, though only used one.
1) The view holder/model pattern e.g. https://www.androidcode.ninja/android-viewholder-pattern-example/ and https://developer.android.com/topic/libraries/architecture/viewmodel where the inflation and finding items re-used / separated from onCreateView activities.
I did not use this method
2) Create bare bones views for the dynamic ones (The first view was static and then there were 2 dynamic ones at positions 1 and 2 that contained listviews of different aspects of the dynamic data.)
The listviews were inflated and had an adapter set to an empty list in onCreateView of these views thus they were fast to create.
Then I added an on OnPageChangeListener which notified the adapter backing the ViewPager that the pages had changed
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
if (position == 1 || position == 2)
{
mSectionsPagerAdapter.notifyDataSetChanged();
}
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// Code goes here
}
#Override
public void onPageScrollStateChanged(int state) {
// Code goes here
}
});
The notifyDataSetChanged causes the viewPager to call getItemPosition in the FragmentStatePagerAdapter class to work out if the page position has changed and it if need to re-create it in the a new position.
Then in FragmentStatePagerAdapter extended class I overrode getItemPosition with
#Override
public int getItemPosition(Object object) {
if (object instanceof LogFragment) {
LogFragment f = (LogFragment) object;
if (f != null) {
f.update();
}
} else if (object instanceof SummaryFragment){
SummaryFragment f = (SummaryFragment) object;
if (f != null) {
f.update();
}
} else {
return POSITION_UNCHANGED;
}
return super.getItemPosition(object);
}
This allowed me to get the Fragment object and then call the update method on it but still returning POSITION_UNCHANGED so the viewpager did not try and re-create the Fragments.
Then in the update method of the Fragment I get the listview adapter and update the data.
public void update(){
adapter.clear();
adapter.addAll(datasource.getData());
}
Thus the more costly getting and display the dynamic data is only done when the page is actually display, NOT when it is pre-created by viewPager (because that pre-created view would be old out of date data anyway and would need to be updated)
There is one downside to this approach, the screen shown during the swipe is still the old data (either empty or data from when that page was last updated), this was acceptable to me.
I am using firebase database with firebaseui's FirebaseRecyclerAdapter. I have followed the example here:
https://github.com/firebase/FirebaseUI-Android/tree/master/database
-except I'm using a fragment.
The app works fine and I am having no issues except that when the device is rotated the recycler view does not restore its scroll position and instead resets to the top item.
- for example user scrolls 8 items down and then rotates device. user should be in the same scroll position, but instead position has returned to top.
I guess I could just put in additional code to handle this and scroll to the correct position, but I know from experience that the RecyclerView should handle this on its own. does the the FirebaseRecyclerAdapter require me to handle this?
Answering my own question-
The only way I've been able to get this to work is to save state like this:
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mRvPositionIndex = mLayoutManager.findFirstVisibleItemPosition();
View startView = mRecyclerView.getChildAt(0);
mRvTopView = (startView == null) ? 0 : (startView.getTop() - mRecyclerView.getPaddingTop());
outState.putInt(RV_POS_INDEX, mRvPositionIndex);
outState.putInt(RV_TOP_VIEW, mRvTopView);
}
and then in onCreateView(), right after I set the adapter I do this
if (savedInstanceState != null) {
mRvPositionIndex = savedInstanceState.getInt(RV_POS_INDEX);
mRvTopView = savedInstanceState.getInt(RV_TOP_VIEW);
mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
public void onItemRangeInserted(int positionStart, int itemCount) {
mLayoutManager.scrollToPositionWithOffset(mRvPositionIndex, mRvTopView);
}
});
}
I've done a little testing so far but seems to work fine. If someone has a better solution please let me know.
I found also that solution that works fine even in a normal activity
in onCreate:
mDataObserver = new RecyclerView.AdapterDataObserver() {
#Override
public void onItemRangeInserted(int positionStart, int itemCount) {
mLayoutManager.scrollToPositionWithOffset(mRvPositionIndex, 0);
}
};
myFirebaseRecyclerAdapter.registerAdapterDataObserver(mDataObserver);
don't forget to unregister the AdapterDataObserver.
I have Recycler view which lays inside of SwipeRefreshLayout. Also, have ability to open each item in another activity.
After returning back to Recycler I need scroll to chosen item, or to previous Y.
How to do that?
Yes, I googled, found articles in StackOverFlow about saving instance of layout manager, like this one: RecyclerView store / restore state between activities.
But, it doesn't help me.
UPDATE
Right now I have this kind of resolving problem, but, of course, it also doesn't work.
private int scrollPosition;
...//onViewCreated - it is fragment
recyclerView.setHasFixedSize(true);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(llm);
data = new ArrayList<>();
adapter.setData(getActivity(), data);
recyclerView.setAdapter(adapter);
...
#Override
public void onResume() {
super.onResume();
recyclerView.setScrollY(scrollPosition);
}
#Override
public void onPause() {
super.onPause();
scrollPosition = recyclerView.getScrollY();
}
Yes, I have tried scrollTo(int, int) - doen't work.
Now I tried just scroll, for example, to Y = 100, but it doesn't scrolling at all.
Save the current state of recycle view position #onPause:
positionIndex= llManager.findFirstVisibleItemPosition();
View startView = rv.getChildAt(0);
topView = (startView == null) ? 0 : (startView.getTop() - rv.getPaddingTop());
Restore the scroll position #onResume:
if (positionIndex!= -1) {
llManager.scrollToPositionWithOffset(positionIndex, topView);
}
or another way can be #onPause:
long currentVisiblePosition = 0;
currentVisiblePosition = ((LinearLayoutManager)rv.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
restore #onResume:
((LinearLayoutManager) rv.getLayoutManager()).scrollToPosition(currentVisiblePosition);
currentVisiblePosition = 0;
A lot of these answers seem to be over complicating it.
The LayoutManager supports onRestoreInstanceState out of the box so there is no need to save scroll positions etc. The built in method already saves pixel perfect positions.
example fragment code (null checking etc removed for clarity):
private Parcelable listState;
private RecyclerView list;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
listState=savedInstanceState.getParcelable("ListState");
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelable("ListState", list.getLayoutManager().onSaveInstanceState());
}
then just call
list.getLayoutManager().onRestoreInstanceState(listState);
once your data has been reattached to your RecyclerView
Beginning from version 1.2.0-alpha02 of androidx recyclerView library, it is now automatically managed. Just add it with:
implementation "androidx.recyclerview:recyclerview:1.2.0-alpha02"
And use:
adapter.stateRestorationPolicy = StateRestorationPolicy.PREVENT_WHEN_EMPTY
The StateRestorationPolicy enum has 3 options:
ALLOW — the default state, that restores the RecyclerView state immediately, in the next layout pass
PREVENT_WHEN_EMPTY — restores the RecyclerView state only when the adapter is not empty (adapter.getItemCount() > 0). If your data is loaded async, the RecyclerView waits until data is loaded and only then the state is restored. If you have default items, like headers or load progress indicators as part of your Adapter, then you should use the PREVENT option, unless the default items are added using MergeAdapter. MergeAdapter waits for all of its adapters to be ready and only then it restores the state.
PREVENT — all state restoration is deferred until you set ALLOW or PREVENT_WHEN_EMPTY.
Note that at the time of this answer, recyclerView library is still in alpha03, but alpha phase is not suitable for production purposes.
User your recycler view linearlayoutmanager for getting scroll position
int position = 0;
if (linearLayoutManager != null) {
scrollPosition = inearLayoutManager.findFirstVisibleItemPosition();
}
and when restoring use following code
if (linearLayoutManager != null) {
cardRecyclerView.scrollToPosition(mScrollPosition);
}
Hope this helps you
to save position to Preferences, add this to your onStop()
int currentVisiblePosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
getPreferences(MODE_PRIVATE).edit().putInt("listPosition", currentVisiblePosition).apply();
then restore position like this
if (getItemCount() == 0) {
int savedListPosition = getPreferences(MODE_PRIVATE).getInt("listPosition", 0);
recyclerView.getLayoutManager().scrollToPosition(savedListPosition); }
this last code should be added inside an event of the Adapter (not sure witch event but in my case was onEvent() - com.google.firebase.firestore.EventListener)
For some reason there are a lot of quite misleading tips/suggestions on how to save and restore scroll position in your_scrolling_container upon orientation changes.
Taking current scroll position and saving it in Activity’s onSaveInstanceState
Extending a certain scrollable View to do same there
Preventing Activity from being destroyed on rotation
And yeah, they are working fine, but…
But in fact, everything is much simpler, because Android is already doing it for you!
If you take a closer look at
RecyclerView/ListView/ScrollView/NestedScrollView sources, you’ll see that each of them is saving its scroll position in onSaveInstanceState. And during the first layout pass they are trying to scroll to this position in onLayout method.
There are only 2 things you need to do, to make sure it’s gonna work fine:
Set an id for your scrollable view, which is probably already done. Otherwise Android won’t be able to save View state automatically.
Provide a data before the first layout pass, to have the same scroll boundaries you had before rotation. That’s the step where developers usually have some issues.
The easiest and transition compatible way I found is:
#Override
public void onPause() {
super.onPause();
recyclerView.setLayoutFrozen(true);
}
#Override
public void onResume() {
super.onResume();
recyclerView.setLayoutFrozen(false);
}
in onSaveInstanceState() method of fragment you can save the scroll position of RecycleView
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
LinearLayoutManager layoutManager = (LinearLayoutManager)
recyclerView.getLayoutManager();
outState.putInt("scrolled_position",
layoutManager.findFirstCompletelyVisibleItemPosition());
}
then you can retrieve saved scroll position in onViewStateRestored() method
#Override
public void onViewStateRestored(#Nullable Bundle savedInstanceState) {
super.onViewStateRestored(savedInstanceState);
if (savedInstanceState != null) {
int scrollPosition = savedInstanceState.getInt("scrolled_position");
recyclerView.scrollToPosition(scrollPosition);
}
}
You can use scrollToPosition or smoothScrollToPosition to scroll to any item position in RecyclerView.
If you want to scroll to item position in adapter, then you would have to use adapter's scrollToPosition or smoothScrollToPosition.
I'm new to Android and I'm trying to do the following task on my school project:
I have a grid view of movies which the user can scroll endlessly.
When the app starts I fetch the first 20 movies and each time the user scrolls to the bottom of the grid I execute an AsyncTask to fetch 20 more movies and add them to the Adapter.
When the user clicks on a movie he goes to a new child activity to see the movie details.
I'm having troubles maintaining the GridView's scroll position in the following cases:
When the user goes to the details activity and returns to the main activity of the movies.
When the user changes the device orientation.
And when dealing with theses 2 cases I also need to take in consideration that maybe the user scrolled a lot and had 100 movies in the adapter and when he goes back the activity start from the start with only the first 20 movies, so I would be able to scroll to his last position.
Can someone please tell me how can I give the best user experience in my project by not losing the user's scroll position at any case?
I don't know if this is the best practice, but in my case it is.
I decided to set my adapter as a global static variable, in this way I maintain the amount of data loaded via the API, and I don't need to perform a request for every time the user moves between activities.
For maintaining the scroll position I used the onItemClickListener when moving to the details activity and the savedInstanceState when changing orientation.
Here is my code for that:
//Static variables
private static MoviesAdapter mMoviesAdapter;
private static int mGridViewPosition = 0;
//Call this method when user clicks the back button
public static void ClearStaticData(){
mMoviesAdapter.clear();
mMoviesAdapter = null;
}
#Override
public void onSaveInstanceState(Bundle outState) {
int index = mGridView.getFirstVisiblePosition();
outState.putInt(GRID_VIEW_POSITION, index);
super.onSaveInstanceState(outState);
}
#Override
public View onCreateView(...) {
if (mMoviesAdapter == null) {
mMoviesAdapter = new MoviesAdapter(...);
} else {
RestoreGridPosition();
}
}
private void RestoreGridPosition(){
if(mGridViewPosition > 0 && mMoviesAdapter.getCount() >= mGridViewPosition)
mGridView.setSelection(mGridViewPosition);
}
Since I fill my adapter via API call, I think this is probably the best solution to save the data and not to perform requests every time.
Try not finishing mainActivity once a gridItem is clicked so when user navigates back to mainActivity (from detailsActivity) he will have all the data that was there before.
You can handle this situation with activity's lifecycle callbacks:
You can get currently visible GridView item's position like this:
int mCurrentPosition = gridview.getFirstVisiblePosition();
When an orientation change is occurring the activity is recreated and going through the following stages:
onSaveInstanceState
onRestoreInstanceState
You can then save the position before orientation change is happening and get it back when its being restored.
Save Your Activity State
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the user's current scroll state
savedInstanceState.putInt(STATE_POSITION, mCurrentPosition);
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(savedInstanceState);
}
Restore Your Activity State
public void onRestoreInstanceState(Bundle savedInstanceState) {
// Always call the superclass so it can restore the view hierarchy
super.onRestoreInstanceState(savedInstanceState);
// Restore state members from saved instance
mCurrentPosition = savedInstanceState.getInt(STATE_POSITION);
}
Here once you have the previous position you can move to the desired position in the gridView:
gridview.smoothScrollToPosition(int mCurrentPosition)
This is taken from android docs: Recreating an Activity
Scrolling gridView to position GridView scrolling stackoverflow
How does one refresh the data displayed in RecyclerView (calling notifyDataSetChanged on its adapter) and make sure that the scroll position is reset to exactly where it was?
In case of good ol' ListView all it takes is retrieving getChildAt(0), checking its getTop() and calling setSelectionFromTop with the same exact data afterwards.
It doesn't seem to be possible in case of RecyclerView.
I guess I'm supposed to use its LayoutManager which indeed provides scrollToPositionWithOffset(int position, int offset), but what's the proper way to retrieve the position and the offset?
layoutManager.findFirstVisibleItemPosition() and layoutManager.getChildAt(0).getTop()?
Or is there a more elegant way to get the job done?
I use this one.^_^
// Save state
private Parcelable recyclerViewState;
recyclerViewState = recyclerView.getLayoutManager().onSaveInstanceState();
// Restore state
recyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);
It is simpler, hope it will help you!
I have quite similar problem. And I came up with following solution.
Using notifyDataSetChanged is a bad idea. You should be more specific, then RecyclerView will save scroll state for you.
For example, if you only need to refresh, or in other words, you want each view to be rebinded, just do this:
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
EDIT: To restore the exact same apparent position, as in, make it look exactly like it did, we need to do something a bit different (See below how to restore the exact scrollY value):
Save the position and offset like this:
LinearLayoutManager manager = (LinearLayoutManager) mRecycler.getLayoutManager();
int firstItem = manager.findFirstVisibleItemPosition();
View firstItemView = manager.findViewByPosition(firstItem);
float topOffset = firstItemView.getTop();
outState.putInt(ARGS_SCROLL_POS, firstItem);
outState.putFloat(ARGS_SCROLL_OFFSET, topOffset);
And then restore the scroll like this:
LinearLayoutManager manager = (LinearLayoutManager) mRecycler.getLayoutManager();
manager.scrollToPositionWithOffset(mStatePos, (int) mStateOffset);
This restores the list to its exact apparent position. Apparent because it will look the same to the user, but it will not have the same scrollY value (because of possible differences in landscape/portrait layout dimensions).
Note that this only works with LinearLayoutManager.
--- Below how to restore the exact scrollY, which will likely make the list look different ---
Apply an OnScrollListener like so:
private int mScrollY;
private RecyclerView.OnScrollListener mTotalScrollListener = new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
mScrollY += dy;
}
};
This will store the exact scroll position at all times in mScrollY.
Store this variable in your Bundle, and restore it in state restoration to a different variable, we'll call it mStateScrollY.
After state restoration and after your RecyclerView has reset all its data reset the scroll with this:
mRecyclerView.scrollBy(0, mStateScrollY);
That's it.
Beware, that you restore the scroll to a different variable, this is important, because the OnScrollListener will be called with .scrollBy() and subsequently will set mScrollY to the value stored in mStateScrollY. If you do not do this mScrollY will have double the scroll value (because the OnScrollListener works with deltas, not absolute scrolls).
State saving in activities can be achieved like this:
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(ARGS_SCROLL_Y, mScrollY);
}
And to restore call this in your onCreate():
if(savedState != null){
mStateScrollY = savedState.getInt(ARGS_SCROLL_Y, 0);
}
State saving in fragments works in a similar way, but the actual state saving needs a bit of extra work, but there are plenty of articles dealing with that, so you shouldn't have a problem finding out how, the principles of saving the scrollY and restoring it remain the same.
Keep scroll position by using #DawnYu answer to wrap notifyDataSetChanged() like this:
val recyclerViewState = recyclerView.layoutManager?.onSaveInstanceState()
adapter.notifyDataSetChanged()
recyclerView.layoutManager?.onRestoreInstanceState(recyclerViewState)
Yes you can resolve this issue by making the adapter constructor only one time, I am explaining the coding part here :
if (appointmentListAdapter == null) {
appointmentListAdapter = new AppointmentListAdapter(AppointmentsActivity.this);
appointmentListAdapter.addAppointmentListData(appointmentList);
appointmentListAdapter.setOnStatusChangeListener(onStatusChangeListener);
appointmentRecyclerView.setAdapter(appointmentListAdapter);
} else {
appointmentListAdapter.addAppointmentListData(appointmentList);
appointmentListAdapter.notifyDataSetChanged();
}
Now you can see I have checked the adapter is null or not and only initialize when it is null.
If adapter is not null then I am assured that I have initialized my adapter at least one time.
So I will just add list to adapter and call notifydatasetchanged.
RecyclerView always holds the last position scrolled, therefore you don't have to store last position, just call notifydatasetchanged, recycler view always refresh data without going to top.
Thanks
Happy Coding
The top answer by #DawnYu works, but the recyclerview will first scroll to the top, then go back to the intended scroll position causing a "flicker like" reaction which isn't pleasant.
To refresh the recyclerView, especially after coming from another activity, without flickering, and maintaining the scroll position, you need to do the following.
Ensure you are updating you recycler view using DiffUtil. Read more about that here: https://www.journaldev.com/20873/android-recyclerview-diffutil
Onresume of your activity, or at the point you want to update your activity, load data to your recyclerview. Using the diffUtil, only the updates will be made on the recyclerview while maintaining it position.
Hope this helps.
Here is an option for people who use DataBinding for RecyclerView.
I have var recyclerViewState: Parcelable? in my adapter. And I use a BindingAdapter with a variation of #DawnYu's answer to set and update data in the RecyclerView:
#BindingAdapter("items")
fun setRecyclerViewItems(
recyclerView: RecyclerView,
items: List<RecyclerViewItem>?
) {
var adapter = (recyclerView.adapter as? RecyclerViewAdapter)
if (adapter == null) {
adapter = RecyclerViewAdapter()
recyclerView.adapter = adapter
}
adapter.recyclerViewState = recyclerView.layoutManager?.onSaveInstanceState()
// the main idea is in this call with a lambda. It allows to avoid blinking on data update
adapter.submitList(items.orEmpty()) {
adapter.recyclerViewState?.let {
recyclerView.layoutManager?.onRestoreInstanceState(it)
}
}
}
Finally, the XML part looks like:
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/possible_trips_rv"
android:layout_width="match_parent"
android:layout_height="0dp"
app:items="#{viewState.yourItems}"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"/>
I was making a mistake like this, maybe it will help someone :)
If you use recyclerView.setAdapter every time new data come, it calls the adapter clear() method every time you use it, which causes the recyclerview to refresh and start over. To get rid of this, you need to use adapter.notiftyDatasetChanced().
1- You need to save scroll position like this
rvProduct.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
recyclerViewState = rvProduct.getLayoutManager().onSaveInstanceState(); // save recycleView state
}
});
2- And after you call notifyDataSetChanged then onRestoreInstanceState like this example
productsByBrandAdapter.addData(productCompareList);
productsByBrandAdapter.notifyDataSetChanged();
rvProduct.getLayoutManager().onRestoreInstanceState(recyclerViewState); // restore recycleView state
I have not used Recyclerview but I did it on ListView. Sample code in Recyclerview:
setOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
rowPos = mLayoutManager.findFirstVisibleItemPosition();
It is the listener when user is scrolling. The performance overhead is not significant. And the first visible position is accurate this way.
Create Extention and use it entirely your App, if you are using DiffUtil you don't need to add adapter.notifyDataSetChanged()
fun RecyclerView.reStoreState(){
val recyclerViewState = this.layoutManager?.onSaveInstanceState()
this.layoutManager?.onRestoreInstanceState(recyclerViewState)
}
Then use it like this below
yourRecyclerView.reStoreState()
adapter.submitList(yourData)
yourRecyclerView.adapter = adapter
#BindingAdapter("items")
fun <T> RecyclerView.setItems(items: List<T>?) {
(adapter as? ListAdapter<T, *>)?.submitList(items) {
layoutManager?.onSaveInstanceState().let {
layoutManager?.onRestoreInstanceState(it)
}
}
}
mMessageAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
#Override
public void onChanged() {
mLayoutManager.smoothScrollToPosition(mMessageRecycler, null, mMessageAdapter.getItemCount());
}
});
The solution here is to keep on scrolling recyclerview when new message comes.
The onChanged() method detects the action performed on recyclerview.
That's working for me in Kotlin.
Create the Adapter and hand over your data in the constructor
class LEDRecyclerAdapter (var currentPole: Pole): RecyclerView.Adapter<RecyclerView.ViewHolder>() { ... }
change this property and call notifyDataSetChanged()
adapter.currentPole = pole
adapter.notifyDataSetChanged()
The scroll offset doesn't change.
If you have one or more EditTexts inside of a recyclerview items, disable the autofocus of these, putting this configuration in the parent view of recyclerview:
android:focusable="true"
android:focusableInTouchMode="true"
I had this issue when I started another activity launched from a recyclerview item, when I came back and set an update of one field in one item with notifyItemChanged(position) the scroll of RV moves, and my conclusion was that, the autofocus of EditText Items, the code above solved my issue.
best.
Just return if the oldPosition and position is same;
private int oldPosition = -1;
public void notifyItemSetChanged(int position, boolean hasDownloaded) {
if (oldPosition == position) {
return;
}
oldPosition = position;
RLog.d(TAG, " notifyItemSetChanged :: " + position);
DBMessageModel m = mMessages.get(position);
m.setVideoHasDownloaded(hasDownloaded);
notifyItemChanged(position, m);
}
I had this problem with a list of items which each had a time in minutes until they were 'due' and needed updating. I'd update the data and then after, call
orderAdapter.notifyDataSetChanged();
and it'd scroll to the top every time. I replaced that with
for(int i = 0; i < orderArrayList.size(); i++){
orderAdapter.notifyItemChanged(i);
}
and it was fine. None of the other methods in this thread worked for me. In using this method though, it made each individual item flash when it was updated so I also had to put this in the parent fragment's onCreateView
RecyclerView.ItemAnimator animator = orderRecycler.getItemAnimator();
if (animator instanceof SimpleItemAnimator) {
((SimpleItemAnimator) animator).setSupportsChangeAnimations(false);
}