all tasks

Task/Simple-windowed-application/Clojure/simple-windowed-application.clj

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+(ns counter-window
+  (:import (javax.swing JFrame JLabel JButton)))
+
+(defmacro on-action [component event & body]
+  `(. ~component addActionListener
+      (proxy [java.awt.event.ActionListener] []
+        (actionPerformed [~event] ~@body))))
+
+(defn counter-app []
+  (let [counter (atom 0)
+        label (JLabel. "There have been no clicks yet")
+        button (doto (JButton. "Click me!")
+                 (on-action evnt
+                   (.setText label
+                      (str "Counter: " (swap! counter inc)))))
+        panel (doto (JPanel.)
+                (.setOpaque true)
+                (.add label)
+                (.add button))]
+    (doto (JFrame. "Counter App")
+      (.setContentPane panel)
+      (.setSize 300 100)
+      (.setDefaultCloseOperation JFrame/EXIT_ON_CLOSE)
+      (.setVisible true))))