Solved

Scrolling on a JPanel

Posted on 2006-07-23
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Last Modified: 2012-06-27
Hi
i have the following applet : www.tykkebror.dk/scroll
source:
www.tykkebror.dk/scroll/ImagePanel.java
www.tykkebror.dk/scroll/JPanelScroll.java

The applet is just a JPanel with a scrollpane. I want the applet to scroll up and down the image when the mouse is near the edge. My only problem is that I cant get rid of the flickering. Everytime the image is scrolled it flickers or draws strange white lines across it. It doesnt matter if I use the "mouse near the edge thing" or I use the scrollbar it still destroys the graphic. My questions is:
1. Is there an easier more correct way to do the "mouse near the edge thing"?
2. How do I remove the flickering/white lines?

Comments on structure of code or other suggestion are most welcome.

Thx in advance :)
tykkebror
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Question by:tykkebror
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4 Comments
 
LVL 92

Accepted Solution

by:
objects earned 400 total points
ID: 17164366
In JPanelScroll use a JApplet instead of an Applet
And don't override paint()
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LVL 92

Expert Comment

by:objects
ID: 17164375
>                     ((JPanel)currentEvent.getSource()).scrollRectToVisible(scrollRect);

This call should also be made from the event dispatch thread using EventQueue.invokeLater()


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Author Comment

by:tykkebror
ID: 17164749
Thx both of you

Changing the Applet to JApplet and removing the paint method from JPanelScroll sure removed some of the flickering.
Using the EventQueue.invokeLater() method to call ((JPanel)currentEvent.getSource()).scrollRectToVisible(scrollRect); removed the rest.

new applet: www.tykkebror.d/scroll/edit
new source:
www.tykkebror.dk/scroll/edit/ImagePanel.java
www.tykkebror.dk/scroll/edit/JPanelScroll.java

Thank you
0
 

Author Comment

by:tykkebror
ID: 17164779
arrrrrgh why cant i edit my comments. Why cant I redo stuff.
My new applet url should be www.tykkebror.dk/scroll/edit

ohh and objects just posted twice ... same person :)
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