I am a beginer in JavaFx.
I hava an existing desktop Swing application. I was wondering if it is posible to keep the existing code (the db access procedures, the "logic" etc.) and change only the SWING interface with a JavaFX one. I have found many tutorials about how to create a JavaFx interface (display elements etc.) but I don't really know how to "call" my old standard Java Code from it (ex: when I click an Fx button to trigger the code previously written for a SWING listener).
It's been a while since I've done any JavaFX work, but I believe that JavaFX for the desktop can use anything from Java SE, including database connectivity. This will prevent your application from being portable; it probably won't be able to run on mobile phones or TVs et all.
As for how, do you know how to call a method from a button trigger? Calling a JavaFX method or a Java method won't be that different, as long as you have the right imports and you have an instance to call the method on (not needed for static methods).
Since JavaONE 2010, all JavaFX Script 1.X is deprecated. JavaFX Sciprt will be reincarnated as JavaFX 2.0 as a regular Java library sometime in Spring 2011. Then all Java JavaFX interactions will be moot. JavaFX Script was compiled with JavaFX compiler. But JavaFX 2.0 will be compiled with the Java compiler (javac). And JavaFX will be accessible from all languages on the VM as any Java Library might be. The question will be how much of the JavaFX Script functionality will survive in JavaFX 2.0.