Fix menu updates in the multiwin example.

AUTHORS

@@ -7,3 +7,4 @@ Google LLC
 Raph Levien
 Hilmar Gústafsson
 Dmitry Borodin
+Kaiyin Zhong

CHANGELOG.md

@@ -134,6 +134,7 @@ This means that druid no longer requires cairo on macOS and uses Core Graphics i
 - Removed references to cairo on macOS. ([#943] by [@xStrom])
 - Updated screenshots in `README.md`. ([#967] by [@xStrom])
 - Added a section about dependencies to `CONTRIBUTING.md`. ([#990] by [@xStrom])
+- Fixed menu inconsistency across multiple windows in the multiwin example. ([#926] by [@kindlychung])
 
 ### Maintenance
 
@@ -216,6 +217,7 @@ This means that druid no longer requires cairo on macOS and uses Core Graphics i
 [#920]: https://github.com/xi-editor/druid/pull/920
 [#924]: https://github.com/xi-editor/druid/pull/924
 [#925]: https://github.com/xi-editor/druid/pull/925
+[#926]: https://github.com/xi-editor/druid/pull/926 
 [#928]: https://github.com/xi-editor/druid/pull/928
 [#930]: https://github.com/xi-editor/druid/pull/930
 [#931]: https://github.com/xi-editor/druid/pull/931

druid/examples/multiwin.rs

@@ -18,11 +18,11 @@ use druid::widget::prelude::*;
 use druid::widget::{
     Align, BackgroundBrush, Button, Controller, ControllerHost, Flex, Label, Padding,
 };
+use druid::Target::Global;
 use druid::{
     commands as sys_cmds, AppDelegate, AppLauncher, Application, Color, Command, ContextMenu, Data,
     DelegateCtx, LocalizedString, MenuDesc, MenuItem, Selector, Target, WindowDesc, WindowId,
 };
-
 use log::info;
 
 const MENU_COUNT_ACTION: Selector = Selector::new("menu-count-action");
@@ -46,7 +46,9 @@ pub fn main() {
             LocalizedString::new("multiwin-demo-window-title").with_placeholder("Many windows!"),
         );
     AppLauncher::with_window(main_window)
-        .delegate(Delegate)
+        .delegate(Delegate {
+            windows: Vec::new(),
+        })
         .launch(State::default())
         .expect("launch failed");
 }
@@ -55,14 +57,10 @@ fn ui_builder() -> impl Widget<State> {
     let text = LocalizedString::new("hello-counter")
         .with_arg("count", |data: &State, _env| data.menu_count.into());
     let label = Label::new(text);
-    let inc_button = Button::<State>::new("Add menu item").on_click(|ctx, data, _env| {
-        data.menu_count += 1;
-        ctx.set_menu(make_menu::<State>(data));
-    });
-    let dec_button = Button::<State>::new("Remove menu item").on_click(|ctx, data, _env| {
-        data.menu_count = data.menu_count.saturating_sub(1);
-        ctx.set_menu(make_menu::<State>(data));
-    });
+    let inc_button = Button::<State>::new("Add menu item")
+        .on_click(|ctx, _data, _env| ctx.submit_command(MENU_INCREMENT_ACTION, Global));
+    let dec_button = Button::<State>::new("Remove menu item")
+        .on_click(|ctx, _data, _env| ctx.submit_command(MENU_DECREMENT_ACTION, Global));
     let new_button = Button::<State>::new("New window").on_click(|ctx, _data, _env| {
         ctx.submit_command(sys_cmds::NEW_FILE, Target::Global);
     });
@@ -132,6 +130,9 @@ impl<W: Widget<State>> Widget<State> for Glow<W> {
 }
 
 struct ContextMenuController;
+struct Delegate {
+    windows: Vec<WindowId>,
+}
 
 impl<T, W: Widget<T>> Controller<T, W> for ContextMenuController {
     fn event(&mut self, child: &mut W, ctx: &mut EventCtx, event: &Event, data: &mut T, env: &Env) {
@@ -145,46 +146,50 @@ impl<T, W: Widget<T>> Controller<T, W> for ContextMenuController {
     }
 }
 
-struct Delegate;
-
 impl AppDelegate<State> for Delegate {
     fn command(
         &mut self,
         ctx: &mut DelegateCtx,
-        target: Target,
+        _target: Target,
         cmd: &Command,
         data: &mut State,
         _env: &Env,
     ) -> bool {
-        match (target, &cmd.selector) {
-            (_, &sys_cmds::NEW_FILE) => {
-                let window = WindowDesc::new(ui_builder)
+        match cmd.selector {
+            sys_cmds::NEW_FILE => {
+                let new_win = WindowDesc::new(ui_builder)
                     .menu(make_menu(data))
                     .window_size((data.selected as f64 * 100.0 + 300.0, 500.0));
-                ctx.new_window(window);
+                ctx.new_window(new_win);
                 false
             }
-            (Target::Window(id), &MENU_COUNT_ACTION) => {
+            MENU_COUNT_ACTION => {
                 data.selected = *cmd.get_object().unwrap();
                 let menu = make_menu::<State>(data);
-                ctx.set_menu(menu, id);
+                for id in &self.windows {
+                    ctx.set_menu(menu.clone(), *id);
+                }
                 false
             }
             // wouldn't it be nice if a menu (like a button) could just mutate state
             // directly if desired?
-            (Target::Window(id), &MENU_INCREMENT_ACTION) => {
+            MENU_INCREMENT_ACTION => {
                 data.menu_count += 1;
                 let menu = make_menu::<State>(data);
-                ctx.set_menu(menu, id);
+                for id in &self.windows {
+                    ctx.set_menu(menu.clone(), *id);
+                }
                 false
             }
-            (Target::Window(id), &MENU_DECREMENT_ACTION) => {
+            MENU_DECREMENT_ACTION => {
                 data.menu_count = data.menu_count.saturating_sub(1);
                 let menu = make_menu::<State>(data);
-                ctx.set_menu(menu, id);
+                for id in &self.windows {
+                    ctx.set_menu(menu.clone(), *id);
+                }
                 false
             }
-            (_, &MENU_SWITCH_GLOW_ACTION) => {
+            MENU_SWITCH_GLOW_ACTION => {
                 data.glow_hot = !data.glow_hot;
                 false
             }
@@ -200,7 +205,9 @@ impl AppDelegate<State> for Delegate {
         _ctx: &mut DelegateCtx,
     ) {
         info!("Window added, id: {:?}", id);
+        self.windows.push(id);
     }
+
     fn window_removed(
         &mut self,
         id: WindowId,
@@ -209,6 +216,9 @@ impl AppDelegate<State> for Delegate {
         _ctx: &mut DelegateCtx,
     ) {
         info!("Window removed, id: {:?}", id);
+        if let Some(pos) = self.windows.iter().position(|x| *x == id) {
+            self.windows.remove(pos);
+        }
     }
 }