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JFrame

 
Ben Buchli
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hi everybody,
I have a JFrame and added a JPanel to it, now how do I force shapes drawn to appear in this JPanel?
Thanks for the help!
Ben
 
Ernest Friedman-Hill
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  • Write a subclass of JPanel, and use that instead of JPanel itself.
  • In your subclass, override paintComponent(Graphics).
  • In the first line of your override, call super.paintComponent(Graphics).
  • Then draw your shapes.

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    Ben Buchli
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    Thanks, Ernest.
    It works...
    how would I find that out without help???
    now another question i have regarding panels. is it possible to add a ScrollPane to the Panel so that it becomes scrollable when the shapes are moved and not completely visible in the pane?
    how would i do that?
    thanks in advance
    [ May 04, 2004: Message edited by: Ben Buchli ]
     
    Eddie Vanda
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    Instead of adding your subclassed JPanel to the JFrame's Container instance (from getContentPane), use it as the argument to constructing a new JScrollPane and then add that JScrollPane instance to your Container instance.
    So if your JPanel subclass is MyJPanel and the instance is myJPanel, then instead of using add (myJpanel), use:
     
    Ben Buchli
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    Thanks, Eddie, thats what I did.
    However, the problem is that when the shape gets drawn outside of the viewing window (which means it's not or only partially visible) then I want to have scroll bars available for the user to scroll.
    How do I do that?? I have the scrollbars, but somehow, they stay disabled...
    thanks,
    Ben
     
    Craig Wood
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    The idea is to override getPreferredSize in our drawing component and to keep it apprised of the changing width and height requirements during the drawing. As we update the width and height fields we call revalidate on the drawing component which tells the scrollpane we need more space.
    Here's an example:
     
    Ben Buchli
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    Thanks a lot Craig,
    seems to work...
     
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