More varied image selection dialog layout

[smichel17]

What's the the image selection dialog?

It's the pop-up which is used by most quests that have a two-part selection. For example, in the cycleway quest, you tap a side and then there's a pop-up to pick the type of cycleway. There are some images in #771 (comment) and it appears several times in the video just above.

@westnordost, @matkoniecz, and other SC developers who have implemented quests: Right now, the image selection dialog reserves the same space for every item. When you were building the UI, have you ever wanted a more varied layout?

I'm asking because when I was thinking about the maxweight sign in #3557 (comment), I thought it would be nice to have the "not listed" option extend across the entire bottom row, something like:

I took a quick look at the source, and I think it would be too much effort to justify for just this one quest (and a "quick & dirty" solution would not be appropriate, because the image_select is used in many places). However, if a more varied layout is something that you've wished for in other places, then this might be a good time to implement a way to do that generically.

[matkoniecz]

When you were building the UI, have you ever wanted a more varied layout?

No, so far I never had any use for it.

[smichel17]

For future reference— I missed this the first time around, but there is actually already is code to handle this

StreetComplete/app/src/main/java/de/westnordost/streetcomplete/view/image_select/GroupedImageSelectAdapter.kt

Lines 38 to 42 in 583da60

	gridLayoutManager.spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {
	override fun getSpanSize(position: Int): Int {
	return if (_items[position].isGroup) gridLayoutManager.spanCount else 1
	}
	}

It only handles a single special case— an item which is a group should span the whole width —but it's easy enough to add other cases there.

[smichel17]

@westnordost I noticed that in GroupedImageSelectAdapter, both in the lines above and onCreateViewHolder, we have some logic like, "If the view is a group, use one layout, otherwise use another". Would it make any sense to pull that out into the DisplayItem? That way each DisplayItem can define its own layout. Or is there a better way to allow something like the mockup in the original post?