I don't think I understand what you mean. You would just have as many item fragments as you have visible cells on screen?

the ListView will use TodoItemList cell for empty and recycled cells too, right?

@carlw That's the whole point, but it only creates the number of cells it needs to support the viewport of the listview 🙂

number of cells is fine, but you're keeping the ItemFragments around too

Yes, one per cell?

Are you afraid of having twenty ItemFragments instantiated? 🙂

no, just an implementation that might keep more than 20

Huh?

if ListView chooses to keep 65k in memory and recycle these

to ease scrolling

Of course it doesn't do that. That's the whole point of the VirtualFlow 🙂 You can easily try this. Add this init block to your TodoItemModel:

@User uploaded a file: Untitled

Then you can add the following to the init block of the ItemFragment:

@User uploaded a file: Untitled

After that, you can relax 🙂

Get crazy and scroll around, you will see that the list view does it's job. If it created 65k list cell items, the problem would already be huge.

one sec...stashing my changes

This does however reveal some other huge performance issues with the implementation. It seems something is doing list scanning somewhere.

One thing that has to be rewritten is that you add new listeners in the load function. This should only be done once, when the FXML is loaded.

(And that is much easier with a ViewModel in place)

yes it creates the listcells on demand with scrolling, but how does ItemFragment get free'd?

@carlw Why should they get free'd? There is one per list cell, and you only have enough list cells to fit your screen, ever.

They will be garbage collected when the ListView is not referenced anymore 🙂

what's the syntax for a destructor in kotlin?

destructor?

does kotlin have de-init {} method?

thats an old EJB method 🙂

havent seen that one in ages

There is no need to do any cleanup whatsoever with this approach. I'll change your sample to include a ViewModel and rewrite the Fragment tomorrow so I can show you what I mean @carlw 🙂

i thought i read something in the kotlin docs about a destroy() method