Java2D -> ArrayList + Button click = drawing on JPanel

Hello there,

I am trying to do something that should be fairly simple, or so I'm told.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































I'm just starting to learn Java, btw.

You're using Eclipse and you created a Java Swing Application window.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































You added an ArrayList of rectangles, a button to the left, and a custom JPanel to the right.

Note that the arraylist is not defined in the button or custom jpanel class. The reason is that its defined by user input. You see, in this app (pdf imposition app) I wrote some code that calculates the best imposition on a sheet for a given pdf and the arraylist holds the position and dimensions for each pdf rectangle/shape.

Now, you're the programmer...































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































Here's here's the scenario you want to see happening.

1-) The user click the impose button.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































2-) The custom JPanel clears itself of any previous drawings and draws the rectangles as seen in the ArrayList of rectangles.

So you have three separate things to contend with: an ArrayList of stuff to draw, a button to initiate the drawing, and a custom jpanel to draw on.

How do you do this?

Thanks,

ps: On the internet, most code examples refer to painting that's controlled either at the class creation time or by mouse events inside the component (usually a jpanel) itself. I didn't find any examples where an external component, like a button, controls through its click event the drawing on another component that in turns draws stuff that is defined outside its own class data.

ps2: I would donate a Starbucks card for someone showing me a working example. Smile | :)