This week's book giveaway is in the Java in General forum. We're giving away four copies of Think Java: How to Think Like a Computer Scientist and have Allen B. Downey & Chris Mayfield on-line! See this thread for details.
I'm trying to show a drawing being built-up in a series of iterations. I have a counter and it controls how much of the drawing needs to be completed at the current time. There is a JButton with an ActionListener that increments the counter. The difficulty I'm having is trying to invalidate the drawing so the drawComponent() method gets reinvoked. My application has a JFrame with a multi-pane JTabbedPane. On one of those panes, there is an extension of a JPanel on which I draw. This JPanel also has a couple of JButtons at the bottom. The buttons work, I can see that the counter is incremented. If I grab an edge of the frame and move it, a redraw is triggered and the right parts of the diagram are drawn. What I want is to be able to invalidate the JPanel in the ActionListener for the JButton so it will redraw immediately. I've tried two things so far. 1. I've tried to invalidate the JPanel, and 2. I've tried to invalidate the JFrame. Both executed with no exceptions, but the drawing did not redraw. What am I missing? Thanks in advance.