Accessing the window from a menu item in Cljfx

Question

How can I access the main window (:stage) from a menu click event in Cljfx? I need it for two reasons: to open a file chooser, and to resize the window.

A minimal example:

(ns a
  (:require [cljfx.api :as fx]))

(fx/on-fx-thread
  (fx/create-component
    {:fx/type :stage
     :showing true
     :scene {:fx/type :scene
             :root {:fx/type :v-box
                    :children [{:fx/type :menu-bar
                                :menus [{:fx/type :menu
                                         :text "Test"
                                         :items [{:fx/type :menu-item
                                                  :text "test"
                                                  :on-action #(println %)}]}]}]}}}))

; deps.edn
; {:deps  {org.clojure/clojure {:mvn/version "1.12.0"}
;          cljfx/cljfx         {:mvn/version "1.9.5"}}}

Answer 1

In your ns form (not necessary, but needed to fix reflection warnings if you have (set! *warn-on-reflection* true) in that namespace):

(:import (javafx.event Event)
         (javafx.scene.control MenuItem)
         (javafx.stage PopupWindow))

As a handler for :on-action:

(fn [^Event evt]
  (let [^MenuItem menu-item (.getTarget evt)
        ^PopupWindow menu (.getParentPopup menu-item)
        stage (.getOwnerWindow menu)]
    ...))