feat!(segmented_button): Add context menu support and integrations

examples/nav-context/src/main.rs

@@ -0,0 +1,211 @@
+// Copyright 2023 System76 <info@system76.com>
+// SPDX-License-Identifier: MPL-2.0
+
+//! Application API example
+
+use std::collections::HashMap;
+
+use cosmic::app::{Command, Core, Settings};
+use cosmic::iced_core::Size;
+use cosmic::widget::menu::action::MenuAction;
+use cosmic::widget::menu::menu_tree::{menu_items, MenuItem, MenuTree};
+use cosmic::widget::nav_bar;
+use cosmic::{executor, iced, ApplicationExt, Element};
+
+#[derive(Clone, Copy)]
+pub enum Page {
+    Page1,
+    Page2,
+    Page3,
+    Page4,
+}
+
+impl Page {
+    const fn as_str(self) -> &'static str {
+        match self {
+            Page::Page1 => "Page 1",
+            Page::Page2 => "Page 2",
+            Page::Page3 => "Page 3",
+            Page::Page4 => "Page 4",
+        }
+    }
+}
+
+/// Runs application with these settings
+#[rustfmt::skip]
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tracing_subscriber::fmt::init();
+    let _ = tracing_log::LogTracer::init();
+
+    let input = vec![
+        (Page::Page1, "🖖 Hello from libcosmic.".into()),
+        (Page::Page2, "🌟 This is an example application.".into()),
+        (Page::Page3, "🚧 The libcosmic API is not stable yet.".into()),
+        (Page::Page4, "🚀 Copy the source code and experiment today!".into()),
+    ];
+
+    let settings = Settings::default()
+        .antialiasing(true)
+        .client_decorations(true)
+        .debug(false)
+        .default_icon_theme("Pop")
+        .default_text_size(16.0)
+        .scale_factor(1.0)
+        .size(Size::new(1024., 768.));
+
+    cosmic::app::run::<App>(settings, input)?;
+
+    Ok(())
+}
+
+/// Messages that are used specifically by our [`App`].
+#[derive(Clone, Debug)]
+pub enum Message {
+    NavMenuAction(NavMenuAction),
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum NavMenuAction {
+    MoveUp(nav_bar::Id),
+    MoveDown(nav_bar::Id),
+    Delete(nav_bar::Id),
+}
+
+impl MenuAction for NavMenuAction {
+    type Message = cosmic::app::Message<Message>;
+
+    fn message(&self, _entity: Option<cosmic::widget::segmented_button::Entity>) -> Self::Message {
+        cosmic::app::Message::App(Message::NavMenuAction(*self))
+    }
+}
+
+/// The [`App`] stores application-specific state.
+pub struct App {
+    core: Core,
+    nav_model: nav_bar::Model,
+}
+
+/// Implement [`cosmic::Application`] to integrate with COSMIC.
+impl cosmic::Application for App {
+    /// Default async executor to use with the app.
+    type Executor = executor::Default;
+
+    /// Argument received [`cosmic::Application::new`].
+    type Flags = Vec<(Page, String)>;
+
+    /// Message type specific to our [`App`].
+    type Message = Message;
+
+    /// The unique application ID to supply to the window manager.
+    const APP_ID: &'static str = "org.cosmic.AppDemo";
+
+    fn core(&self) -> &Core {
+        &self.core
+    }
+
+    fn core_mut(&mut self) -> &mut Core {
+        &mut self.core
+    }
+
+    /// Creates the application, and optionally emits command on initialize.
+    fn init(core: Core, input: Self::Flags) -> (Self, Command<Self::Message>) {
+        let mut nav_model = nav_bar::Model::default();
+
+        for (title, content) in input {
+            nav_model.insert().text(title.as_str()).data(content);
+        }
+
+        nav_model.activate_position(0);
+
+        let mut app = App { core, nav_model };
+
+        let command = app.update_title();
+
+        (app, command)
+    }
+
+    /// Allows COSMIC to integrate with your application's [`nav_bar::Model`].
+    fn nav_model(&self) -> Option<&nav_bar::Model> {
+        Some(&self.nav_model)
+    }
+
+    /// The context menu to display for the given nav bar item ID.
+    fn nav_context_menu(
+        &self,
+        id: nav_bar::Id,
+    ) -> Option<Vec<MenuTree<cosmic::app::Message<Self::Message>, cosmic::Renderer>>> {
+        Some(menu_items(
+            &HashMap::new(),
+            vec![
+                MenuItem::Button("Move Up", NavMenuAction::MoveUp(id)),
+                MenuItem::Button("Move Down", NavMenuAction::MoveDown(id)),
+                MenuItem::Button("Delete", NavMenuAction::Delete(id)),
+            ],
+        ))
+    }
+
+    /// Called when a navigation item is selected.
+    fn on_nav_select(&mut self, id: nav_bar::Id) -> Command<Self::Message> {
+        self.nav_model.activate(id);
+        self.update_title()
+    }
+
+    /// Handle application events here.
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        match message {
+            Message::NavMenuAction(message) => match message {
+                NavMenuAction::Delete(id) => self.nav_model.remove(id),
+                NavMenuAction::MoveUp(id) => {
+                    if let Some(pos) = self.nav_model.position(id) {
+                        if pos != 0 {
+                            self.nav_model.position_set(id, pos - 1);
+                        }
+                    }
+                }
+                NavMenuAction::MoveDown(id) => {
+                    if let Some(pos) = self.nav_model.position(id) {
+                        self.nav_model.position_set(id, pos + 1);
+                    }
+                }
+            },
+        }
+
+        Command::none()
+    }
+
+    /// Creates a view after each update.
+    fn view(&self) -> Element<Self::Message> {
+        let page_content = self
+            .nav_model
+            .active_data::<String>()
+            .map_or("No page selected", String::as_str);
+
+        let text = cosmic::widget::text(page_content);
+
+        let centered = cosmic::widget::container(text)
+            .width(iced::Length::Fill)
+            .height(iced::Length::Shrink)
+            .align_x(iced::alignment::Horizontal::Center)
+            .align_y(iced::alignment::Vertical::Center);
+
+        Element::from(centered)
+    }
+}
+
+impl App
+where
+    Self: cosmic::Application,
+{
+    fn active_page_title(&mut self) -> &str {
+        self.nav_model
+            .text(self.nav_model.active())
+            .unwrap_or("Unknown Page")
+    }
+
+    fn update_title(&mut self) -> Command<Message> {
+        let header_title = self.active_page_title().to_owned();
+        let window_title = format!("{header_title} — COSMIC AppDemo");
+        self.set_header_title(header_title);
+        self.set_window_title(window_title)
+    }
+}