Refreshing GUI while MultiThreading

Question

I am trying to refresh a GUI while calling a class that extends the Thread class.My code looks similiar to this:
myThreadingClass mtc=new myThreadingClass();
mtc.start();
while(mtc.isAlive()){
repaint();
invalidate():
The isAlive() is never returning false! ? ! I somehow need to do the repaint while waiting for the thread to finish. I had a mtc.join() before that worked and went on in the program, but I did not have any way to refresh the GUI with the mtc.join().
Any one have any good ideas?

Answer 1

If mtc.isAlive() is always returning true then obviously it hasn't exitted myThreadingClass.run() yet.
So you need to look at what causes run() to exit there.
Also you needto make thread safe calls to Swing by using the SwingUtilities class. Trying to update a Swing component from another thread is inherently unsafe because Swing is non-reentrant.
- Also : You can repaint then invalidate().... should swap that around.
- Also : You're refreshing the screen in a while loop without any delays.
Try putting in a sleep() for a little bit.
regards,
Owen
while ( mtc.isAlive() )
     // IMPORTANT : You can't update a Swing component in another
     // Thread.  You must update it in a "Swing friendly" manner.
     // Hence this helper function.
     try
          Thread.sleep ( 1000 );     // refresh screen once a second... can be changed
     catch (InterruptedException ignore )
     final Runnable runnable = new Runnable()
         public void run()
              invalidate();
              repaint();
         } // run
     };    // runnable
     SwingUtilities.invokeLater(runnable);
}