Alternating images with a timer using java

Question

Since I'm not a CS major, I'm having some difficulties translating my programming wishes into an actual program. What it basically boils down to is the following: how can I alternate an image on a label, showing each image for an amount of tim specific for each image.

So: say I've images A and B; I'd like the user to see A for 1000ms and B for 200ms. This keeps on looping until a user presses a certain key.

Now, I'm able to load an image onto a panel, quite easily even, and I've managed to catch user input using KeyListener and stuff, which all works quite nicely and alot easier then I had expected. I also know how to use looping constructs like while, for and do..while, but this timer business is shady.

I see all kinds of stuff using threads and what not, I really don't need that. This is not about efficient programming or good code, it's simply about demonstrating something. Any help would be greatly appreciated!

Answer 1

Use a SwingWorker<Void, Void>. The doInBackground method of the SwingWorker should look like this :

@Override
protected Void doInBackground() {
    try {
        while (true) {
            displayImage(imageA);
            Thread.sleep(1000L);
            if (isCancelled()) {
                return null;
            }
            displayImage(imageB);
            Thread.sleep(200L);
            if (isCancelled()) {
                return null;
            }
        }
    }
    catch (InterruptedException e) {
        // ignore
    }
    return null;
}

private void displayImage(final Icon image) {
    SwingUtilituies.invokeLater(new Runnable() {
        @Override
        public void run() {
            // display the image in the panel
        }
    });
}

The keylistener should simply cancel the SwingWorker.