A Clojure library for JavaFX
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Guide | API docs | Source | CHANGELOG | License

Clojars Project

Beta quality - the API is pretty stable and has gotten a fair amount of testing. JDK 8 and at least Clojure 1.7.0-alpha3 are required.


A Clojure library for JavaFX 8 with the following goals:

  • Provide convenience functions for creating and modifying JavaFX objects without attempting to completely hide the JavaFX API
  • Work with core.async out of the box
  • Provide support for creating JavaFX objects with both a function based - (fx/h-box (fx/button "Hello World")) - and hiccup-like API - (fx/compile-fx [:h-box [:button "Hello World"]]).
  • Provide an API for modifying nodes with selectors (sort of like enlive) for interacting with FXML resources
  • Allow for setting JavaFX CSS from code and integrate with the garden CSS library
  • Helper functions for i18n
  • Provide data binding to reactive atoms, cursors and expressions (via freactive.core).

Quick Start

Make sure you have installed JDK 8 and have lein configured to use it. See the leiningen sample.project.clj and search for LEIN_JAVA_CMD, :java-cmd and JAVA_CMD to see different ways to do this.

Add the leiningen dependency to your project listed above and a namespace declaration similar to the following to your code:

(ns my-ns
  (:require [fx-clj.core :as fx]))

A "hello world" example:

(ns example
  (:require [fx-clj.core :as fx]))

(defn create-view []
    (fx/button {:on-action (fn [e] (println "Hello World!"))
                :text "Click Me!"})))

(fx/sandbox #'create-view) ;; Creates a "sandbox" JavaFX window to
                           ;; show the view. Clicking F5 in this
                           ;; window will refresh the view allowing the
                           ;; create-view function to be updated at the REPL

A quick example for integrating fx-clj and core.async:

(ns example2
  (:require [fx-clj.core :as fx])
  (:require [clojure.core.async :refer [chan go <! >!]]))

(defn create-view []
  (let [click-ch (chan)
        btn (fx/button :#my-btn {:on-action click-ch ;; You can bind a core.async channel directly to an event
                        :text "Next"})

        txt (fx/text "Initial text")
        view (fx/v-box txt btn)]
      (<! click-ch)
      (fx/run<! (fx/pset! txt "Next text"))
      (<! click-ch)
        (fx/pset! txt "Last text")
        (fx/pset! btn {:text "Done"}))
      (println "Done listening to clicks"))


(fx/sandbox #'create-view)


Interacting with the JavaFX application thread

There are three macros for interacting with the JavaFX application thread - each providing slightly different asynchronous behavior: run!, run<! and run<!!. For those familiar with core.async, these correspond to the behavior of put!, <! and <!! respectively.

run! sends a block of code to be run asynchronously on the JavaFX application thread without blocking the caller. (It is effectively a thin wrapper around javafx.application.Platform/runLater.)

(run! (do-something)) ;; run asynchously without blocking

run<! can only be used in a core.async go block! It uses a core.async channel and <! to return the value of the code executed on the JavaFX application thread to the caller in the go block. (This blocks the go block, but does not block a thread.)

    (let [res (run<! (do-something))] ;; Go block paused
        (println res)))

run<!! uses a core.async channel and <!! to return the value of the code executed on the JavaFX application thread. It blocks the calling thread until the block has completed and returns its value to the caller.

(let [res (run<!! (do-something))] ;; Calling thread blocked
    (println res)))

Modifying JavaFX objects

The pset! function is used to modify JavaFX objects.

The signature for pset! is the following:

(defn pset! [element id-class-keyword? property-map? content-or-children*])

id-class-kw? (optional): a keyword representing a hiccup style ID and classes (i.e. :#some-id.some-class.another-class).

property-map? (optional): a map of property keys and setters. Keys can be kebab-case keywords corresponding to JavaFX bean properties. Values are converted using clojurefx.core.convert/convert-arg. If a value is an instance of ObservableValue (or is converted to one), it will be bound to the property.

content-or-children* (zero or more): element or elements to be bound to the JavaFX element's DefaultProperty. If the DefaultProperty is a list property then multiple children elements can be bound, otherwise only a single 'content' element can be bound.

Creating JavaFX objects

There is both a function-based and hiccup-style API for creating JavaFX objects.

See the API documentation for fx-clj.core for a list of supported JavaFX objects.

The syntax for all object creation functions and the hiccup like vectors, is identical to the pset! syntax after the first argument (for the target element). Choosing between the different styles is basically a matter of preference. All of the following are equivalent:

(fx/button :#my-btn.my-class {:on-action (fn [] (println "Clicked"))} "Click Me")

(fx/compile-fx [:button#my-btn.my-class {:on-action (fn [] (println "Clicked"))}] "Click Me")

(fx/pset! (Button.) :#my-btn.my-class {:on-action (fn [] (println "Clicked"))} "Click Me")

Because the DefaultProperty of Button is text, it can be set by passing a single argument after the property map.

Elements can also be defined using FXML and modified with a selector-based transform (sort of like in enlive) using the at! function. Right now only ID-based selectors are supported. pset! based transforms are supported as well as a limited number of other transforms. See the test example.

Data Binding

The reactive atoms, expressions and cursors from freactive.core can be bound to any JavaFX property. Unfortunately not all of this capability is thoroughly documented - see the fx-clj.core.binding namespace (which is all pulled into fx-clj.core by potemkin) for more info.


Copyright © 2014 Aaron Craelius

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.