OSATParams, TItemViewsHolder Class

Self-explanatory. See ItemCountChangeMode in order to understand how change modes differ from each other.

Every count change operation (Refresh(Boolean, Boolean), InsertItems(Int32, Int32, Boolean, Boolean) etc.) ultimately calls this method, so it's a good place for example to fire a custom "ItemsChanged" event, if you need to

Called when there are no recyclable views for itemIndex. Provide a new viewsholder instance for itemIndex. This is the place where you must initialize the viewsholder

via Init(GameObject, Int32, Boolean, Boolean) shortcut or manually set its itemIndex, instantiate the prefab and call its CollectViews

returns the REAL distance of the item's right (if scroll view is Horizontal) or bottom (if scroll view is Vertical) edge

from the parent's right (respectively, bottm) edge

returns the REAL distance of the item's left (if scroll view is Horizontal) or top (if scroll view is Vertical) edge

from the parent's left (respectively, top) edge

Get the viewsHolder with a specific index in the "visible items" list.

Example: if you pass 0, the first visible ViewsHolder will be returned (if there's any)

Not to be mistaken to the other method 'GetItemViewsHolderIfVisible(int withItemIndex)', which uses the itemIndex, i.e. the index in the list of data models.

Returns null if the supplied parameter is >= VisibleItemsCount

returns the VIRTUAL distance of the item's left (if scroll view is Horizontal) or top (if scroll view is Vertical) edge

from the parent's left (respectively, top) edge

Used internally. Returns values in [0f, 1f] interval, 1 meaning the scrollrect is at start, and 0 meaning end.

It uses a different approach when content size is smaller than viewport's size, so it can yield consistent results for ComputeVisibility(Double)

Initialize the adapter. This is automatically called in Start(), but it may also be called manually, if for some reason you implement Start() and don't want to call base.Start()

Will call Canvas.ForceUpdateCanvases(), Params.InitIfNeeded(), will initialize the internal state and will change the items count to 0

IMPORTANT: Do not call it in Awake(), OnEnable(), OnDisable(). OnStart() is the best place to do it.

Call it when a stolen ViewsHolder won't be added to the adapter and so the adapter should not be responsible for its lifecycle anymore.

If the item was stolen, it'll be unregistered automatically

Called when an insert or remove event happens. You'll only need this if some of your views depend on the item's index itself as opposed to depending only on the model's data

For example, if your item is from a leaderboard and each player's place is given by the order of the models (i.e. you don't have an int in the model named 'place'), you may want to display the item's title as '#233 PlayerName'. This works well if you're only using ResetItems(Int32, Boolean, Boolean), but if you'll call InsertItems(Int32, Int32, Boolean, Boolean) or RemoveItems(Int32, Int32, Boolean, Boolean), the indices of some views holders are shifted, while they'll maintain their data. In this case, you'll override this method and only update the title from its model

This is an important optimization, because you shouldn't update items that are already updated, especially when fetching them from the web

Called mainly when it's detected that the scroll view's size has changed. Marks everything for a layout rebuild and then calls Canvas.ForceUpdateCanvases().

IMPORTANT: Make sure to override MarkForRebuild in your views holder implementation if you have child layout groups and call LayoutRebuilder.MarkForRebuild() on them

An item width/height can be changed with this method.

Should NOT be called during ComputeVisibilityForCurrentPosition(Boolean, Boolean), UpdateViewsHolder(TItemViewsHolder), CreateViewsHolder(Int32) or from any critical view-recycling code. Suggestion: call it from MonBehaviour.Update()

Will change the size of the item's RectTransform to requestedSize and will shift the other items accordingly, if needed.

This can be called in order to schedule a "Twin" ComputeVisibility() call after exactly 1 frame.

A use case is to enable a ContentSizeFitter on your item, call this,

and then disable the ContentSizeFitter in OnItemHeightChangedPreTwinPass(TItemViewsHolder) (or OnItemWidthChangedPreTwinPass(TItemViewsHolder) if horizontal ScrollView)

By default, it aligns the ScrollView's content so that the item with itemIndex will be at the top.

But the two optional parameters can be used for more fine-tuning. One common use-case is to set them both at 0.5 so the item will be end up exactly in the middle of the viewport

Here the data in your model should be bound to the views. Use newOrRecycled.ItemIndex (ItemIndex) to retrieve its associated model

Note that views holders are re-used (this is the main purpose of this adapter), so a views holder's views will contain data from its previously associated model and if,

for example, you're downloading an image to be set as an icon, it makes sense to first clear the previous one (and probably temporarily replace it with a generic "Loading" image)

Note that this is not called for items that will remain visible after an Insert or Remove operation is done