Howto create an explorer-like rectangle selection??

Question

Hi,
I created a more advanced Custom FileChooser, because I didn't like the standard JFileChooser. It works pretty good, but there's one thing I'd like it to have, but I have absolutely no clue on how to program this...
My FileChooser consists of 3 JLists. In one List, there are the files of one folder displayed. Now I would like to implement the ability to drag a rectangle-selection to select multiple files in the JList, just as we know it from the Windows Explorer.
Can you please help me creating that, I don't know how this can be realized, as I've never ever used the paint() and draw-Functions in Java. Also, I can't imagine how to let the rectangle realize, on what files it is drawn, to mark them as selected...
Thank you for help,
Ciao, AntiBit

Answer 1

Well, let's see... I would probably start by setting up a mouse listener as illustrated in the tutorial example referred to above. Use the mousePressed() method to get the first corner of your rectangle and store the x and y values in class variables. Then use the mouseDragged() method to get the next corner x and y values and store these.
At this point, I would have the mouseDragged() method also call repaint() on your glass pane component - the tutorial example provides an overridden paint method for the glass pane component, and you could do the same thing to draw your rectangle. This way, anytime you drag the mouse over it, the glass pane can redraw the rectangle in its new size/position. Might look something like:
public void paint(Graphics g)
   if (x1 >= 0 && y1 >= 0 && x2 >= 0 && y2 >=0)
      g.setColor(Color.black);
      g.drawRect(x1, y1, x2, y2);
}Finally, when mouseReleased() is called, it could reset the variables to -1, which would indicate to your overridden paint() method that no rectangle should be drawn. Hope this helps somewhat - I'm not sure of any specific tutorials that might help - maybe the one on applets?
Good luck