Java – detects when the user has finished resizing the SWT shell

I have a resizable SWT shell Every time I resize, I have to do something computationally intensive

I can register a controllistener on my shell, but this will continuously generate events throughout the resizing operation. I don't know when the resizing drag type mouse operation ends

I want to be able to detect when the user resizes the shell and then start my compute intensive operations Any idea how to do it?

Solution

Use a timer and start the operation after a delay of one second after the last resizing event is received?

long lastEvent;

ActionListener taskPerformer = new ActionListener() {
            public void doCalc(ActionEvent evt) {
                if ( (lastEvent + 1000) < System.currentTimeMillis() ) {
                   hardcoreCalculationTask();
                } else {
                  // this can be timed better
                  new Timer(1000,taskPerformer).start();
                }
            }
        };
}

In your resize event:

lastEvent = System.currentTimeMillis();
 new Timer(1000,taskPerformer).start();