feat(context_menu): add a context menu widget as menu tree alternative to the popover widget

examples/context-menu/src/main.rs

@@ -0,0 +1,144 @@
+// Copyright 2023 System76 <info@system76.com>
+// SPDX-License-Identifier: MPL-2.0
+
+//! Application API example
+
+use cosmic::app::{Command, Core, Settings};
+use cosmic::iced_core::Size;
+use cosmic::widget::{menu, segmented_button};
+use cosmic::{executor, iced, ApplicationExt, Element};
+use std::collections::HashMap;
+
+/// 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 settings = Settings::default()
+        .size(Size::new(1024., 768.));
+
+    cosmic::app::run::<App>(settings, ())?;
+
+    Ok(())
+}
+
+/// Messages that are used specifically by our [`App`].
+#[derive(Clone, Debug)]
+pub enum Message {
+    Clicked,
+    ShowContext,
+    WindowClose,
+    ShowWindowMenu,
+    ToggleHideContent,
+    WindowNew,
+}
+
+/// The [`App`] stores application-specific state.
+pub struct App {
+    core: Core,
+    button_label: String,
+    show_context: bool,
+    hide_content: bool,
+}
+
+/// 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 = ();
+
+    /// 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.ContextMenuDemo";
+
+    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 app = App {
+            core,
+            button_label: String::from("Right click me"),
+            hide_content: false,
+            show_context: false,
+        };
+
+        app.set_header_title("COSMIC Context Menu Demo".into());
+        let command = app.set_window_title("COSMIC Context Menu Demo".into());
+
+        (app, command)
+    }
+
+    /// Handle application events here.
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        self.button_label = format!("Clicked {message:?}");
+
+        Command::none()
+    }
+
+    /// Creates a view after each update.
+    fn view(&self) -> Element<Self::Message> {
+        let widget = cosmic::widget::context_menu(
+            cosmic::widget::button::text(&self.button_label).on_press(Message::Clicked),
+            self.context_menu(),
+        );
+
+        let centered = cosmic::widget::container(widget)
+            .width(iced::Length::Fill)
+            .height(iced::Length::Fill)
+            .align_x(iced::alignment::Horizontal::Center)
+            .align_y(iced::alignment::Vertical::Center);
+
+        Element::from(centered)
+    }
+}
+
+impl App {
+    fn context_menu(&self) -> Option<Vec<menu::Tree<Message>>> {
+        Some(menu::items(
+            &HashMap::new(),
+            vec![
+                menu::Item::Button("New window", ContextMenuAction::WindowNew),
+                menu::Item::Divider,
+                menu::Item::Folder(
+                    "View",
+                    vec![menu::Item::CheckBox(
+                        "Hide content",
+                        self.hide_content,
+                        ContextMenuAction::ToggleHideContent,
+                    )],
+                ),
+                menu::Item::Divider,
+                menu::Item::Button("Quit", ContextMenuAction::WindowClose),
+            ],
+        ))
+    }
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ContextMenuAction {
+    WindowClose,
+    ToggleHideContent,
+    WindowNew,
+}
+
+impl menu::Action for ContextMenuAction {
+    type Message = Message;
+    fn message(&self, _entity_opt: Option<segmented_button::Entity>) -> Self::Message {
+        match self {
+            ContextMenuAction::WindowClose => Message::WindowClose,
+            ContextMenuAction::ToggleHideContent => Message::ToggleHideContent,
+            ContextMenuAction::WindowNew => Message::WindowNew,
+        }
+    }
+}