[FlatList][pythonnative.FlatList] and [SectionList][pythonnative.SectionList] are the two list components shipped with PythonNative. Both support native virtualization: when you supply item_height, the list is backed by UITableView on iOS and RecyclerView on Android, mounting rows lazily as they scroll into view.

Virtualize whenever the list might exceed the viewport. The non-virtualized fallback (ScrollView of every row) is only suitable for short, fixed lists (a settings page, a small menu).

import pythonnative as pn

items = [{"id": i, "title": f"Row {i}"} for i in range(10_000)]


@pn.component
def Big():
    return pn.FlatList(
        data=items,
        item_height=44,
        render_item=lambda item, _: pn.Text(item["title"]),
        key_extractor=lambda item, _: str(item["id"]),
    )

The list never holds 10,000 native views — only the rows currently visible (plus a small reuse pool) ever exist.

Use [RefreshControl][pythonnative.RefreshControl] as a prop on either FlatList or [ScrollView][pythonnative.ScrollView]:

@pn.component
def Pullable():
    refreshing, set_refreshing = pn.use_state(False)

    def reload():
        set_refreshing(True)
        # ... fetch data ...
        set_refreshing(False)

    return pn.FlatList(
        data=items,
        item_height=44,
        refresh_control=pn.RefreshControl(
            refreshing=refreshing,
            on_refresh=reload,
        ),
    )

Pass on_item_press= to receive the tapped row's index:

pn.FlatList(
    data=items,
    item_height=44,
    on_item_press=lambda index: print(f"tapped {items[index]['id']}"),
)

Inside render_item you can also wrap the row in a [Pressable][pythonnative.Pressable] for finer-grained control.

[SectionList][pythonnative.SectionList] flattens an iterable of {"title": ..., "data": [...]} sections into a single virtualized list, dispatching to either render_section_header or render_item depending on the row's kind.

sections = [
    {"title": "A", "data": ["Apple", "Avocado"]},
    {"title": "B", "data": ["Banana", "Blueberry"]},
]

pn.SectionList(
    sections=sections,
    item_height=44,
    section_header_height=32,
    render_section_header=lambda s, _: pn.Text(s["title"]),
    render_item=lambda item, _i, _s: pn.Text(item),
)

item_height and section_header_height are fixed; for variable- height rows the eager fallback (omit item_height) is currently the only option.

• Always provide a stable key_extractor so reused rows refresh in place rather than tearing down and rebuilding their subtree.
• Keep row subtrees shallow. The reconciler is fast, but mounting a hundred Text/Image/Button nodes per row is wasteful work whenever a row recycles.
• Move expensive computation out of render_item (use [use_memo][pythonnative.use_memo] in the parent component, or pre-compute once before constructing the data list).