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 cho
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
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);
}
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.
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)
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;
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