Support GridLayoutManager

[Mariovc]

Quick fix to support GridLayoutManager (without reverse mode), but with the condition of the adapter must draw the first item of each section in a new row.

[jacobtabak]

Was there a need to remove sample data to make this work?

[jacobtabak]

Ah because each header needs to have a multiple of 3 items?

[jacobtabak]

Cool - definitely a good start. We will need to overcome the condition you mentioned before merging this, though. That implementation detail should be abstracted from users of the library.

[Mariovc]

I have removed the condition. The header of the items will correspond to the first item of the row, even if it is not reordered with the method "reorderItems" I've created.

[jacobtabak]

Hi, sorry for the delay in reviewing this. Your code for reordering these items lives within the sample, not the library itself, so the burden of all this extra logic still falls upon the developer.

[Mariovc]

Like I said before. The sticky-headers will work even if the items are not reordered. I considered that reorder or not the items, is a desicion that falls upon the developer, but in both cases you will have sticky-headers

[MartinRajniak]

Hi, @Mariovc thanks for the fix, I am using it in our project and it works fine. The only thing that I also had to do is to add empty items to create sections before headers (something like you do in your reorder code). Maybe this is the last thing missing for it to be merged.

That would unfortunately mean that we would need to extend some BaseAdapter class instead of just implementing interface. I don't know if this is something with which would author, @jacobtabak, agree with, but it would be great to switch to stable master again :)

[mrlem]

If I may, in StickyRecyclerHeadersDecoration, instead of:
if (position == RecyclerView.NO_POSITION || position % mAdapter.getNumColumns() > 0) {

Couldn't you just do:
if (position == RecyclerView.NO_POSITION || itemView.getLeft() != 0) {

(not 100% sure if the left position of the left most item can be something else, but it does work for me)

This way you'd avoid all the nasty numcolumns business, sparing your user a lot of work.

[hendrawd]

Too bad it's not maintained anymore, since this functionality is a good feature to implement i think. I will try it, since i need for grid layout too

[hendrawd]

@MartinRajniak yes, unfortunatelly i got the same problem as you. It would be great if this pull request can also fix the problem.

Expected

What happened instead

[Mariovc]

@hendrawd Maybe I can do that, but this pull request will not be merged probably.

Anyway the user has to provide two criteria to the library:

1. The criteria to order (date order, recent first)
2. The criteria to create a new sticky header (grouped by day)

[hendrawd]

@Mariovc yes too bad :(. Actually i was cloning your github repo directly and import it as a module since this repo is inactive