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Message:

update() method is the key

Posted by Kishori Sharan on July 14, 2001 at 12:43 PM

Hi
The behaviour of frame drawings you are getting is because of the way you have written your update ( Graphics g ) method for Line class. For all heavyweight components the default role of update method is to erase the background first and then call paint method. In your Line class you have overriden the update() method and hence the background that contains your previous drawings are not erased. I am not saying that you have done something wrong. I am just explaining thefact that why are you getting such behaviour. Therefore, if you call super method from update then you don't need to call paint from update and then you will see only one line.
public void update(Graphics g) {
super.update ( g ) ;
System.out.println("update " );
//paint(g); // No need to call this now. super.update will call paint method
}
Or, just take out update() method from your Line class .
Thanks
Kishori

• Futher problem Theesan July 16, 2001 at 4:27 AM (4)
  • Store the line co-ordinates in a vector Kishori Sharan July 16, 2001 at 10:47 PM (3)
    • still prolem in the loop Theesan July 22, 2001 at 4:08 AM (2)
      • Paint method is not synchronized Kishori Sharan July 22, 2001 at 1:11 PM (1)
        • Thanks Theesan July 26, 2001 at 1:09 AM (0)