New RecyclerView Grouping crash on Clear/Insert sequence

[thefex]

New RecyclerView Grouping feature crashes when ObservableCollection is Cleared and then some items are inserted.
It crashes with RecyclerView viewholder incosistency.
Preparing fix.

[thefex]

I have implemented support for Group Child collection INotifyCollectionChanged event supports (add/remove/reset) - dynamic group childs collection.

Turns out that crashes was not a bug in grouping implementation.
Support Library RecyclerView has crash bug - https://code.google.com/p/android/issues/detail?id=77846#c10. It says it's fixed - bullshit (check comments). That bug have crashed my app when I was using grouping. I think it has showed with grouping because there are a lot of Insert/Remove sequence operations.

I will push dynamic child support + crash workaround in a moment.

[thefex]

Pushed pull request with RecyclerView crashes.
I will add INotifyCollectionChanged of Group Child collection support in separate issue.

[Nickolas-]

Hi got the same exceptions , but the problem was with not properly dispatching event. Did you check it ?

[thefex]

it's not an issue with "event dispatching". It just crash with normal ObservableCollection - easy to reproduce when a lot of Remove/Insert sequence calls are made.
Check google issue I have mentioned.

[Nickolas-]

Are you using MvxObservableCollection ? I guess you dispatching event not on UI thread.

[kjeremy]

I would definitely make sure you are doing everything on the UI thread.

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On Mar 8, 2017 7:22 AM, "Nickolas Shpotenko" ***@***.***> wrote: Are you using MvxObservableCollection ? I guess you dispatching event not on UI thread. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1640 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEIBRMFEYQX87kvoQhXudMyOqc2-_BMNks5rjp1sgaJpZM4MUMGM> .

[thefex]

I am using RX DynamicData and I do the thing on UI thread. Well if it was UI thread issue the exception would not be IndexOfOutBoundsException + it would always crash (it does not always crash, just sometimes when Clear + Add is called).

That's the backend(PCL) code which manages list by the way:
searchEventObservable .SelectMany(async x => await GetItemsWithSearchFilter(0, x)) .ObserveOn(SynchronizationContext.Current) .Subscribe(items => { ItemsSource.Clear(); ItemsSource.AddRange(items); RecentSearchResultCount = items.Count(); })

I always Observe on SynchronizationContext.Current (UI thread) so it is impossible.

[Nickolas-]

ObservableCollection not thread safe, so maybe you are invoking insert , remove from different thread that can cause this issues.

[thefex]

I don't, I use RX DynamicData and I always, explictly specify that things related to collection modification should be invoked on Current SynchronizationContext which is in fact UI thread.
Crashes and stack trace indicates that this bug is caused by issue reported on google tracker. Also - workaround described in tracker works fine - if it was UI thread issue i wouldn't see filled, working lists in my app.

[thefex]

I guess I have to implement reproduction sample so you will start to believe that something is fucked up with recyclerview. Will do it and ping you back - but not earlier than on weekend

[kjeremy]

Thanks! A reproduction case would be great.

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On Mar 8, 2017 7:39 AM, "Przemysław Raciborski" ***@***.***> wrote: I guess I have to implement reproduction sample so you will start to believe that something it's fucked with recyclerview. Will do it and ping you back - but not earlier than on weekend — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1640 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEIBRL1XraM_PoC1QUPvKOKIiEleazbmks5rjqGEgaJpZM4MUMGM> .

[Nickolas-]

if you have a test project , I could take a look , what's happening.