Route id

CHANGELOG.md

@@ -58,6 +58,7 @@ You can find its changes [documented below](#070---2021-01-01).
 - Add #[data(eq)] shorthand attribute for Data derive macro ([#1884] by [@Maan2003])
 - X11: detect keyboard layout ([#1779] by [@Maan2003])
 - WindowDesc::with_config ([#1929] by [@Maan2003])
+- `Notification::route` ([#1978] by [@xarvic])
 
 ### Changed
 
@@ -793,8 +794,9 @@ Last release without a changelog :(
 [#1919]: https://github.com/linebender/druid/pull/1919
 [#1929]: https://github.com/linebender/druid/pull/1929
 [#1947]: https://github.com/linebender/druid/pull/1947
-[#1967]: https://github.com/linebender/druid/pull/1967
 [#1953]: https://github.com/linebender/druid/pull/1953
+[#1967]: https://github.com/linebender/druid/pull/1967
+[#1978]: https://github.com/linebender/druid/pull/1978
 
 [Unreleased]: https://github.com/linebender/druid/compare/v0.7.0...master
 [0.7.0]: https://github.com/linebender/druid/compare/v0.6.0...v0.7.0

druid/src/command.rs

@@ -103,6 +103,7 @@ pub struct Notification {
     symbol: SelectorSymbol,
     payload: Arc<dyn Any>,
     source: WidgetId,
+    route: WidgetId,
 }
 
 /// A wrapper type for [`Command`] payloads that should only be used once.
@@ -407,6 +408,7 @@ impl Command {
             symbol: self.symbol,
             payload: self.payload,
             source,
+            route: source,
         }
     }
 
@@ -528,6 +530,34 @@ impl Notification {
     pub fn source(&self) -> WidgetId {
         self.source
     }
+
+    /// Change the route id
+    pub(crate) fn with_route(mut self, widget_id: WidgetId) -> Self {
+        self.route = widget_id;
+        self
+    }
+
+    /// The [`WidgetId`] of the last [`Widget`] that this [`Notification`] was passed through.
+    ///
+    /// # Example
+    ///
+    /// ```ignore
+    /// fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut (), env: &Env) {
+    ///     if let Event::Notification(notification) = event {
+    ///         if notification.route() == self.widget1.id() {
+    ///             // the notification came from inside of widget1
+    ///         }
+    ///         if notification.route() == self.widget2.id() {
+    ///             // the notification came from inside of widget2
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// [`Widget`]: crate::Widget
+    pub fn route(&self) -> WidgetId {
+        self.route
+    }
 }
 
 impl<T: Any> SingleUse<T> {

druid/src/core.rs

@@ -903,7 +903,9 @@ impl<T: Data, W: Widget<T>> WidgetPod<T, W> {
                     inner_ctx.is_handled = false;
                 } else if let Event::Notification(notification) = event {
                     // we will try again with the next parent
-                    inner_ctx.notifications.push_back(notification);
+                    inner_ctx
+                        .notifications
+                        .push_back(notification.with_route(self_id));
                 } else {
                     // could be unchecked but we avoid unsafe in druid :shrug:
                     unreachable!()