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Message:

MultiThreaded Clock Applet

Posted by Monte Gardner on February 27, 2001 at 11:57 AM

I'm trying to make a simple clock
Applet that displays the time
using the Calendar class.
I have a clock class that
descends from (extends) the Thread class.

It has a method calld updateClock() which updates
the labels of the buttons in the applet. I know
this method works because I have a button which
activates it. When I click the button, the clock
is properly updated.
However, I don't want to have to click a button
every time I want the time, so I put continuous
calls to upDateClock and paint() in the
Start() method of the Clock class. When I call
the start method from the applet however, the
applet just doesn't paint untill the start method
is done. Here's a copy of the start method

/**
* continually calls update clock 10 times
* and requessts that the applet be repainted
*/
public void start()
{
//10 seconds of ticking
while (true)
try
{
Thread.sleep(1000); //1 second
}
catch (InterruptedException e)
{
System.out.println(e);
}//end catch

updateClock(); //updates the button labels

System.out.println("Calling paint()");
parent.paint(parent.getGraphics()); //repaints the applet
parent.hour.paint(parent.getGraphics());
}//end infinite while
}//end method

In the applet console, I can see the "Calling paint" message,
so I know paint is beeing called, but the applet just stays
gray unless i force it to be repainted by placing another
window over it.

I guess the short way of saying this is how do you call
the paint method of an applet from within a thread?