Grid being flipped by screen scrolling orientation with DpadSpanSizeLookup.

[NewtonCesarRoncari]

Hi, I'm trying to change the DpadSpanSizeLookup by ViewType, submitting a list with 2 different items, one representing a rail and the other representing a grid item, but the screen rendering becomes incorrect. Performing a top-to-bottom scroll, the grid appears correctly, but when scrolling from bottom to top, the grid becomes inverted

• I'm creating ViewHolder by ViewType

  override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
      if (holder is HorizontalListViewHolder) {
          val item = getItem(position)
          holder.bind(item)
          stateHolder.restore(holder.recyclerView, item.title, holder.adapter)
      } else if (holder is ItemViewHolder) {
          holder.bind(getItem(position).items.first() , null)
      }
  }

https://github.com/rubensousa/DpadRecyclerView/assets/31870695/a22dbcaa-1e52-43d1-9779-1b5da116e631

• is possible to see the situation on my fork on branch master

[rubensousa]

Hi @NewtonCesarRoncari thanks for the bug report. I will have a look at this next week since I won't have time. For now, as a temporary workaround, you should be able to fix this by ensuring an even number of items in the grid (a number divisible by the span count)

[NewtonCesarRoncari]

Great! @rubensousa Thanks for the reply, if you need more info or details, feel free to ask.

[rubensousa]

@NewtonCesarRoncari fix should be here: https://github.com/rubensousa/DpadRecyclerView/pull/158

Can you please pull that to your fork and play around with it a bit? I will release a new version after your feedback

[NewtonCesarRoncari]

Hi @rubensousa, Great, I'll do some tests and give you a feedback.

[NewtonCesarRoncari]

Hi, @rubensousa The getItemViewType method of the adapter is trying to run for positions that do not have rails. In the case of clicking up on the first rail or down on the last rail, it causes an ArrayIndexOutOfBoundsException.

In my example, I am using ListAdapter instead of a MutableListAdapter.

    override fun getItemViewType(position: Int): Int {
        return currentList[position].type.ordinal    // Trhow ArrayIndexOutOfBoundsException
    }

com...sousa.dpadrecyclerview.sample  E  java.lang.ArrayIndexOutOfBoundsException: length=26; index=-1
at java.util.ArrayList.get(ArrayList.java:439)
at java.util.Collections$UnmodifiableList.get(Collections.java:1356)
at com.rubensousa.dpadrecyclerview.sample.ui.screen.list.HorizontalListAdapter.getItemViewType(HorizontalListAdapter.kt:66)
at androidx.recyclerview.widget.NestedAdapterWrapper.getItemViewType(NestedAdapterWrapper.java:146)
at androidx.recyclerview.widget.ConcatAdapterController.getItemViewType(ConcatAdapterController.java:319)
at androidx.recyclerview.widget.ConcatAdapter.getItemViewType(ConcatAdapter.java:178)
at com.rubensousa.dpadrecyclerview.sample.ui.screen.list.ListFragment$setupRecyclerView$1$3.getSpanSize(ListFragment.kt:139)
at com.rubensousa.dpadrecyclerview.layoutmanager.focus.SpanFocusFinder.getNextSpanEnd(SpanFocusFinder.kt:201)
at com.rubensousa.dpadrecyclerview.layoutmanager.focus.SpanFocusFinder.fitsNextInCurrentSpanGroup(SpanFocusFinder.kt:189)
at com.rubensousa.dpadrecyclerview.layoutmanager.focus.SpanFocusFinder.moveToStartOfNextSpanGroup(SpanFocusFinder.kt:164)
at com.rubensousa.dpadrecyclerview.layoutmanager.focus.SpanFocusFinder.findNextSpanPosition(SpanFocusFinder.kt:77)

as a temporary workaround i did this:

     override fun getItemViewType(position: Int): Int {
        val mPosition = position.coerceIn(0, currentList.lastIndex)
        return currentList[mPosition].type.ordinal
    }

• is possible to see the situation on my fork on branch master

[rubensousa]

Thank you for the report once again. This should be easy to address. So everything else was fine, correct?

[NewtonCesarRoncari]

Yes, the rest is working perfectly 👍

[rubensousa]

@NewtonCesarRoncari fix is now available in 1.1.0-alpha03