A Java related question

[Nyxos]

I have this computer project where I need to recognize letters and signatures to identify someone.

I have 2 questions about Jpanels :

first, how do I erase the drawing that is in the Jpanel so that another drawing can be made by over (if the guy did a mistake and wants to correct). I need it to go blank again and delete all points that might be there.



second, how do I tell if there is something drawn in a Jpanel ? So that the user doesn't validate without having drawn something.

I might have some other questions later, but right now those are the only pressing matters.

And yes, I am a noob.

Thanks a lot.

Nyx.

[english tyrant]

Googled: "Clearing a Jpanel"
Result: http://www.coderanch.com/t/345317/GU...ore-repainting

JPanel panel = new JPanel();
//remove all components in panel.
panel.removeAll();
// refresh the panel.
panel.updateUI();

[Nyxos]

Googled: "Clearing a Jpanel"
Result: http://www.coderanch.com/t/345317/GU...ore-repainting

thanks ! I had the removeAll part but not the updateUI lol I hate programming ...

On a related matter I'm not sure it empties the table where the points are, it seems to do so since I'm not having errors or such and the number of points I get seems reasonable but I want to make sure there isn't a dumb way to empty a table, like table = null;

And for those of you that might think I can't use google or ask my teacher, I'd like to say that every time my teacher has helped she broke half the program, and that google.fr is crap

+ rep btw for having a better google than I