Infinite List widget from upstream feature/list-widget-reloaded branch

Author: hecrj

examples/list/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "list"
+version = "0.1.0"
+authors = ["Héctor Ramón Jiménez <[email protected]>"]
+edition = "2021"
+publish = false
+
+[dependencies]
+iced.workspace = true
+iced.features = ["debug"]

examples/list/src/main.rs

@@ -0,0 +1,92 @@
+use iced::widget::{
+    button, center, column, container, horizontal_space, list, row, scrollable,
+    text,
+};
+use iced::{Alignment, Element, Length, Theme};
+
+pub fn main() -> iced::Result {
+    iced::program("List - Iced", List::update, List::view)
+        .theme(|_| Theme::TokyoNight)
+        .run()
+}
+
+struct List {
+    content: list::Content<(usize, State)>,
+}
+
+#[derive(Debug, Clone, Copy)]
+enum Message {
+    Update(usize),
+    Remove(usize),
+}
+
+impl List {
+    fn update(&mut self, message: Message) {
+        match message {
+            Message::Update(index) => {
+                if let Some((_id, state)) = self.content.get_mut(index) {
+                    *state = State::Updated;
+                }
+            }
+            Message::Remove(index) => {
+                let _ = self.content.remove(index);
+            }
+        }
+    }
+
+    fn view(&self) -> Element<Message> {
+        center(
+            scrollable(
+                container(list(&self.content, |index, (id, state)| {
+                    row![
+                        match state {
+                            State::Idle =>
+                                Element::from(text(format!("I am item {id}!"))),
+                            State::Updated => center(
+                                column![
+                                    text(format!("I am item {id}!")),
+                                    text("... but different!")
+                                ]
+                                .spacing(20)
+                            )
+                            .height(300)
+                            .into(),
+                        },
+                        horizontal_space(),
+                        button("Update").on_press_maybe(
+                            matches!(state, State::Idle)
+                                .then_some(Message::Update(index))
+                        ),
+                        button("Remove")
+                            .on_press(Message::Remove(index))
+                            .style(button::danger)
+                    ]
+                    .spacing(10)
+                    .padding(5)
+                    .align_items(Alignment::Center)
+                    .into()
+                }))
+                .padding(10),
+            )
+            .width(Length::Fill),
+        )
+        .padding(10)
+        .into()
+    }
+}
+
+impl Default for List {
+    fn default() -> Self {
+        Self {
+            content: list::Content::from_iter(
+                (0..1_000).map(|id| (id, State::Idle)),
+            ),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum State {
+    Idle,
+    Updated,
+}

widget/src/helpers.rs

@@ -8,6 +8,7 @@ use crate::core::widget::operation::{self, Operation};
 use crate::core::window;
 use crate::core::{Element, Length, Pixels, Widget};
 use crate::keyed;
+use crate::list::{self, List};
 use crate::overlay;
 use crate::pane_grid::{self, PaneGrid};
 use crate::pick_list::{self, PickList};
@@ -814,6 +815,18 @@ where
     Scrollable::new(content)
 }
 
+/// Creates a new [`List`] with the provided [`Content`] and
+/// closure to view an item of the [`List`].
+///
+/// [`List`]: crate::List
+/// [`Content`]: crate::list::Content
+pub fn list<'a, T, Message, Theme, Renderer>(
+    content: &'a list::Content<T>,
+    view_item: impl Fn(usize, &'a T) -> Element<'a, Message, Theme, Renderer> + 'a,
+) -> List<'a, T, Message, Theme, Renderer> {
+    List::new(content, view_item)
+}
+
 /// Creates a new [`Button`] with the provided content.
 ///
 /// # Example

widget/src/lib.rs

@@ -20,6 +20,7 @@ pub mod checkbox;
 pub mod combo_box;
 pub mod container;
 pub mod keyed;
+pub mod list;
 pub mod overlay;
 pub mod pane_grid;
 pub mod pick_list;
@@ -56,6 +57,8 @@ pub use combo_box::ComboBox;
 #[doc(no_inline)]
 pub use container::Container;
 #[doc(no_inline)]
+pub use list::List;
+#[doc(no_inline)]
 pub use mouse_area::MouseArea;
 #[doc(no_inline)]
 pub use pane_grid::PaneGrid;