Periodically change JLabel icon

Question

I have to change the the icon of a jLabel every 2 seconds. I use a Timer and a Timer task to do this, but it only shows the first image. Here is the code:

    ImageIcon[] icons = {new ImageIcon(this.getClass().getResource("orange.jpg")), new     
    ImageIcon(this.getClass().getResource("cosmote.jpg")), new 
    ImageIcon(this.getClass().getResource("vodafone.jpg"))};
    java.util.Timer timer = new java.util.Timer();
    int indexIcon;

And then in the JFrame constructor:

    initComponents();
    open(fisierAgenda);
    TimerTask task = new TimerTask() {
        public void run() {
            indexIcon=(indexIcon++)%3;
            jLabel.setIcon(icons[indexIcon]);
            jLabel.setText(""+indexIcon);
        }
    };
    timer.schedule(task, 0, 2000);

Any help would be much appreciated.

Implement a **Swing** `Timer` for repeating tasks. See [Concurrency in Swing](http://docs.oracle.com/javase/tutorial/uiswing/concurrency/) for more details. See also this [working example](http://stackoverflow.com/a/13512826/418556). — Andrew Thompson, May 22 '13 at 13:01

score 3 · Accepted Answer · answered May 22 '13 at 13:01

you have an issue with Concurency in Swing
Swing is Single Threaded and all events must be done on EDT
output from util.Timer never will be notifyed Event Dispatch Thread, without any changes to the already visible Swing GUI
use Swing Timer, then output will be always done on EDT

score -1 · Answer 2 · answered May 22 '13 at 12:58

-1

You should use a thread for this. At least, that's what I would use.

answered May 22 '13 at 12:58

Jasper Ketelaar

86
4

1

Not the down-voter, but all edits and updates to Swing GUIs should be on the EDT. – Andrew Thompson May 22 '13 at 13:03
1

Not the down-voter either but: 1) All updates should be done on the EDT (so the simplest thing is to use a Swing Timer) 2) Since Java 1.5, you are better off using the `Executors` framework rather than create `Thread`'s manually. 3) If needed, you can combine `Executors` and `SwingUtilities.invokeLater()` – Guillaume Polet May 22 '13 at 13:16

Periodically change JLabel icon

2 Answers2