Merge pull request #1393 from iced-rs/deprecate-stateful-widgets

Replace stateful widgets with the new `iced_pure` API

3 files changed, 108 insertions, 13 deletions

diff --git a/native/src/overlay.rs b/native/src/overlay.rs
index 792d2905..905d3389 100644
--- a/native/src/overlay.rs
+++ b/native/src/overlay.rs
@@ -10,6 +10,8 @@ use crate::event::{self, Event};
 use crate::layout;
 use crate::mouse;
 use crate::renderer;
+use crate::widget;
+use crate::widget::tree::{self, Tree};
 use crate::{Clipboard, Layout, Point, Rectangle, Shell, Size};
 
 /// An interactive component that can be displayed on top of other widgets.
@@ -40,6 +42,36 @@ where
         cursor_position: Point,
     );
 
+    /// Returns the [`Tag`] of the [`Widget`].
+    ///
+    /// [`Tag`]: tree::Tag
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::stateless()
+    }
+
+    /// Returns the [`State`] of the [`Widget`].
+    ///
+    /// [`State`]: tree::State
+    fn state(&self) -> tree::State {
+        tree::State::None
+    }
+
+    /// Returns the state [`Tree`] of the children of the [`Widget`].
+    fn children(&self) -> Vec<Tree> {
+        Vec::new()
+    }
+
+    /// Reconciliates the [`Widget`] with the provided [`Tree`].
+    fn diff(&self, _tree: &mut Tree) {}
+
+    /// Applies an [`Operation`] to the [`Widget`].
+    fn operate(
+        &self,
+        _layout: Layout<'_>,
+        _operation: &mut dyn widget::Operation<Message>,
+    ) {
+    }
+
     /// Processes a runtime [`Event`].
     ///
     /// It receives:
@@ -77,3 +109,26 @@ where
         mouse::Interaction::Idle
     }
 }
+
+/// Obtains the first overlay [`Element`] found in the given children.
+///
+/// This method will generally only be used by advanced users that are
+/// implementing the [`Widget`](crate::Widget) trait.
+pub fn from_children<'a, Message, Renderer>(
+    children: &'a [crate::Element<'_, Message, Renderer>],
+    tree: &'a mut Tree,
+    layout: Layout<'_>,
+    renderer: &Renderer,
+) -> Option<Element<'a, Message, Renderer>>
+where
+    Renderer: crate::Renderer,
+{
+    children
+        .iter()
+        .zip(&mut tree.children)
+        .zip(layout.children())
+        .filter_map(|((child, state), layout)| {
+            child.as_widget().overlay(state, layout, renderer)
+        })
+        .next()
+}
diff --git a/native/src/overlay/element.rs b/native/src/overlay/element.rs
index de2e1f37..b919c221 100644
--- a/native/src/overlay/element.rs
+++ b/native/src/overlay/element.rs
@@ -4,6 +4,7 @@ use crate::event::{self, Event};
 use crate::layout;
 use crate::mouse;
 use crate::renderer;
+use crate::widget;
 use crate::{Clipboard, Layout, Point, Rectangle, Shell, Size, Vector};
 
 /// A generic [`Overlay`].
@@ -102,6 +103,15 @@ where
         self.overlay
             .draw(renderer, theme, style, layout, cursor_position)
     }
+
+    /// Applies an [`Operation`] to the [`Element`].
+    pub fn operate(
+        &self,
+        layout: Layout<'_>,
+        operation: &mut dyn widget::Operation<Message>,
+    ) {
+        self.overlay.operate(layout, operation);
+    }
 }
 
 struct Map<'a, A, B, Renderer> {
diff --git a/native/src/overlay/menu.rs b/native/src/overlay/menu.rs
index 7b8d4d9e..08135872 100644
--- a/native/src/overlay/menu.rs
+++ b/native/src/overlay/menu.rs
@@ -9,6 +9,7 @@ use crate::text::{self, Text};
 use crate::touch;
 use crate::widget::container::{self, Container};
 use crate::widget::scrollable::{self, Scrollable};
+use crate::widget::tree::{self, Tree};
 use crate::{
     Clipboard, Color, Element, Layout, Length, Padding, Point, Rectangle,
     Shell, Size, Vector, Widget,
@@ -114,15 +115,23 @@ where
 }
 
 /// The local state of a [`Menu`].
-#[derive(Debug, Clone, Default)]
+#[derive(Debug)]
 pub struct State {
-    scrollable: scrollable::State,
+    tree: Tree,
 }
 
 impl State {
     /// Creates a new [`State`] for a [`Menu`].
     pub fn new() -> Self {
-        Self::default()
+        Self {
+            tree: Tree::empty(),
+        }
+    }
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self::new()
     }
 }
 
@@ -131,6 +140,7 @@ where
     Renderer: crate::Renderer,
     Renderer::Theme: StyleSheet + container::StyleSheet,
 {
+    state: &'a mut Tree,
     container: Container<'a, Message, Renderer>,
     width: u16,
     target_height: f32,
@@ -161,18 +171,20 @@ where
             style,
         } = menu;
 
-        let container =
-            Container::new(Scrollable::new(&mut state.scrollable).push(List {
-                options,
-                hovered_option,
-                last_selection,
-                font,
-                text_size,
-                padding,
-                style,
-            }));
+        let container = Container::new(Scrollable::new(List {
+            options,
+            hovered_option,
+            last_selection,
+            font,
+            text_size,
+            padding,
+            style,
+        }));
+
+        state.tree.diff(&container as &dyn Widget<_, _>);
 
         Self {
+            state: &mut state.tree,
             container,
             width,
             target_height,
@@ -187,6 +199,18 @@ where
     Renderer: text::Renderer,
     Renderer::Theme: StyleSheet + container::StyleSheet,
 {
+    fn tag(&self) -> tree::Tag {
+        self.container.tag()
+    }
+
+    fn state(&self) -> tree::State {
+        self.container.state()
+    }
+
+    fn children(&self) -> Vec<Tree> {
+        self.container.children()
+    }
+
     fn layout(
         &self,
         renderer: &Renderer,
@@ -230,6 +254,7 @@ where
         shell: &mut Shell<'_, Message>,
     ) -> event::Status {
         self.container.on_event(
+            self.state,
             event,
             layout,
             cursor_position,
@@ -247,6 +272,7 @@ where
         renderer: &Renderer,
     ) -> mouse::Interaction {
         self.container.mouse_interaction(
+            self.state,
             layout,
             cursor_position,
             viewport,
@@ -279,6 +305,7 @@ where
         );
 
         self.container.draw(
+            self.state,
             renderer,
             theme,
             style,
@@ -344,6 +371,7 @@ where
 
     fn on_event(
         &mut self,
+        _state: &mut Tree,
         event: Event,
         layout: Layout<'_>,
         cursor_position: Point,
@@ -407,6 +435,7 @@ where
 
     fn mouse_interaction(
         &self,
+        _state: &Tree,
         layout: Layout<'_>,
         cursor_position: Point,
         _viewport: &Rectangle,
@@ -423,6 +452,7 @@ where
 
     fn draw(
         &self,
+        _state: &Tree,
         renderer: &mut Renderer,
         theme: &Renderer::Theme,
         _style: &renderer::Style,