Initial implementation of Expander widget

examples/cosmic/src/main.rs

@@ -7,7 +7,7 @@ use cosmic::{
         list_view,
         nav_button,
         toggler,
-        HeaderBar, nav_bar_style,
+        HeaderBar, nav_bar_style, Expander, ExpanderMsg,
     },
     settings,
     iced::{self, theme, Alignment, Application, Color, Command, Element, Length, Theme},
@@ -41,6 +41,7 @@ pub fn main() -> cosmic::iced::Result {
 #[derive(Default)]
 struct Window {
     headerbar: HeaderBar,
+    expander: Expander,
     page: u8,
     debug: bool,
     theme: Theme,
@@ -61,7 +62,8 @@ enum Message {
     CheckboxToggled(bool),
     TogglerToggled(bool),
     PickListSelected(&'static str),
-    Window(WindowMsg)
+    Window(WindowMsg),
+    Expander(ExpanderMsg)
 }
 
 impl From<WindowMsg> for Message {
@@ -70,6 +72,12 @@ impl From<WindowMsg> for Message {
     }
 }
 
+impl From<ExpanderMsg> for Message {
+    fn from(message: ExpanderMsg) -> Self {
+        Self::Expander(message)
+    }
+}
+
 impl Application for Window {
     type Executor = iced::executor::Default;
     type Flags = ();
@@ -109,6 +117,9 @@ impl Application for Window {
                 WindowMsg::Minimize => {}
                 WindowMsg::Maximize => {}
             }
+            Message::Expander(msg) => match msg {
+                ExpanderMsg::Expand => self.expander.expanded = !self.expander.expanded,
+            }
         }
 
         iced::Command::none()
@@ -116,6 +127,7 @@ impl Application for Window {
 
     fn view(&self) -> Element<Message> {
         let mut header = self.headerbar.render();
+        // let expander = self.expander.render();
         if self.debug {
             header = header.explain(Color::WHITE);
         }
@@ -137,7 +149,14 @@ impl Application for Window {
                 ,
                 nav_button!("system-software-update", "OS Upgrade & Recovery", condensed)
                     .on_press(Message::Page(2))
-                    .style(if self.page == 2 { theme::Button::Primary } else { theme::Button::Text })
+                    .style(if self.page == 2 { theme::Button::Primary } else { theme::Button::Text }),
+                self.expander.render(
+                    vec![
+                        text("Content").into(),
+                        text("Content 2").into(),
+                        text("Content 3").into()
+                    ]
+                ),
             ]
             .active(self.headerbar.sidebar_active)
             .condensed(condensed)

src/widget/expander.rs

@@ -0,0 +1,81 @@
+use std::vec;
+
+use apply::Apply;
+use iced::{
+    Element,
+    Length,
+    widget::{
+        row, 
+        horizontal_space, button, container, text, Column
+    }, alignment::{Vertical, Horizontal}, theme 
+};
+use iced_native::widget::column;
+
+#[derive(Default)]
+pub struct Expander
+{
+    pub expanded: bool
+}
+
+#[derive(Clone, Copy, Debug)]
+pub enum ExpanderMsg {
+    Expand,
+}
+
+impl Expander {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn render<'a, T>(&self, children: Vec<Element<'a, T>>) -> Element<'a, T> 
+        where T: Clone + From<ExpanderMsg> + 'static
+    {
+        let title = text("Title")
+            .size(18)
+            .vertical_alignment(Vertical::Center)
+            .horizontal_alignment(Horizontal::Center)
+            .into();
+        let subtitle = iced::widget::text("Subtitle")
+            .size(14)
+            .vertical_alignment(Vertical::Center)
+            .horizontal_alignment(Horizontal::Center)
+            .into();
+        let header = column(
+            vec![title, subtitle]
+        ).into();
+        let space = horizontal_space(Length::Fill).into();
+        let icon = super::icon(
+            if self.expanded {
+                "go-down-symbolic"
+            } else {
+                "go-next-symbolic"
+            },
+            16
+        )
+        .apply(button)
+        .on_press(T::from(ExpanderMsg::Expand))
+        .width(Length::Units(25))
+        .into();
+    
+        container(
+            column(
+                if self.expanded {
+                    vec![
+                        row(vec![header, space, icon]).into(),
+                        container(
+                            Column::with_children(children)
+                        )
+                        .style(theme::Container::Transparent)
+                        .padding(5)
+                        .into()
+                    ]
+                } else {
+                    vec![row(vec![header, space, icon]).into()]
+                }
+            )
+            .padding(5)
+        )
+        .style(theme::Container::Box)
+        .into()
+    }
+}

src/widget/mod.rs

@@ -20,4 +20,7 @@ mod toggler;
 pub use toggler::*;
 
 mod scrollable;
-pub use scrollable::*;
+pub use scrollable::*;
+
+mod expander;
+pub use expander::*;

src/widget/navbar.rs

@@ -321,14 +321,14 @@ where
     Renderer: iced_native::Renderer + 'a,
     Renderer::Theme: StyleSheet,
 {
-    fn from(row: NavBar<'a, Message, Renderer>) -> Self {
-        Self::new(row)
+    fn from(navbar: NavBar<'a, Message, Renderer>) -> Self {
+        Self::new(navbar)
     }
 }
 
-/// Creates a [Row`] with the given children.
+/// Creates a [NavBar`] with the given children.
 ///
-/// [`Row`]: widget::Row
+/// [`NavBar`]: widget::NavBar
 #[macro_export]
 macro_rules! navbar {
     ($($x:expr),+ $(,)?) => (