If auto-sort list by checked items is enabled, separate checked items list

[PhilKes]

Describe the solution you'd like
Currently if you use "Sort checked items to the end" for the list auto-sort, the checked items are moved to the end of the list, but kept in the same RecyclerView. This leads to a much more complex implementation for dragging and sorting, therefore the lists should be split into unchecked and checked items to simplify the implementation. This would also make the code less error-prone, since it has potential for lots of bugs, see e.g. #361 #357 #362, etc.

Additional context
Google Keep also separates checked from unchecked:

[PhilKes]

@andiandi13 I just added a custom NotallyX-7.1.0-BETA-CheckedList.apk to the latest BETA release.
This includes the current development state of this issue. I am not completely finished with it, so its prone to errors, but since I am out of town until Tuesday I wanted to give you an apk to test it out in general, if you want to of course. The other "normal" BETA apk is still available too.

[andiandi13]

@PhilKes Thank you 👍

[andiandi13]

I'll post bugs I found here as I test the app by editing this post

1. Unchecked items can only be moved by one position.

PS : I like the fact that items are instantly send below/above when checked/unchecked. Before we could see them "falling" more or less faster depending on their position, and it wasn't looking very nice, but I think it's a consequence of this bug.

2. New items are added to first position when using "Enter" with keyboard, instead of being adding after the current edited item (however it works with the very last item)

3. Nothing to do with this APK in particular, but when scrollbar is aligned with a delete icon, it's very hard to touch it (but I understand why you made scroll bar box wider, it's more convenient). I always find left margin too big, with items being pushed far at right, so maybe pushing everything left by reducing drag icon margins would solve that :

4. I can move a subtask to the first position and it doesn't transform to parent task

5. Check a box twice before it goes to the uncheck items view, it'll crash with this error : LOG

6. Swapping item 2 with item 1 prevent the new second item (the one that was in first position before) to be set to child, like it keeps it first item property.

7. Create this list :

1
2
   3
   4

Check 4, then move 3 outside of the subtask group, like that :

1
3
2
   4

Only 4 will be checked, when it's supposed to refresh, check 2, and send both to the checked view.

8. Search only work for unchecked items

[PhilKes]

@andiandi13 Tried to fix all your points, except 7. since this is a bug that was present before all this, so please create a separate issue for it. About the drag handle margin being to big, I remember having a complaint with somebody having issue with those android swipe gestures to e.g. navigate back. I decreased the margin for now.
You can download the new BETA (CheckedList suffix)

[andiandi13]

@PhilKes Thank you. I see that you only reduced the margin for unchecked items, so it's still hard to delete items when scrollbar is overlapping

[PhilKes]

@PhilKes Thank you. I see that you only reduced the margin for unchecked items, so it's still hard to delete items when scrollbar is overlapping

The drag handle margin has no effect on the position of the delete button, what screen size do you have? Because there is lots of space to the delete button on my emulator (6.1") and personal device:

Note: I enabled the visibility of the drag handle here for test purposes

[andiandi13]

@PhilKes Google Pixel 4a 5.81" - 443dpi

Look how hard it is (the video is cut a bit earlier but it get delete just after when I tap a bit more left)

deleteicon.mp4