CODEWITHSUNDEEP
swingjscrollpanejtextpane
H2ONaCl
H2ONaCl

Reputation: 11279

JTextPane liveness

My Swing application prints lines of text to a JTextPane inside of a JScrollPane when a JButton is pressed. For quick operations there is no issue. However, some JButtons invoke operations that may take a few minutes. The button remains greyed out during this time.

What currently happens is that the text is "batched up" and then I get hundreds of lines all at once at the end of the operation at the same moment the button becomes un-greyed. The problem is that I would like the text being appended to the document displayed in the JTextPane to appear sooner (at the moment it is appended) rather than at the time the entire operation completes. This would create a better user experience.

What am I doing wrong?

Upvotes: 3

Views: 85

Answers (2)

Marc-Christian Schulze
Marc-Christian Schulze

Reputation: 3254

Use a SwingWorker for performing your background operation.

// Your button handler
public void actionPerformed(ActionEvent e) {
  (new SwingWorker<Void, String>() {
    public Void doInBackground() {
      // perform your operation
      // invoke publish("your string");
    }

    protected void process(List<String> chunks) {
      // append your string to the scroll pane
    }
  }).execute();
}

Upvotes: 2

Guillaume Polet
Guillaume Polet

Reputation: 47608

You are invoking code directly from within the AWT-Thread which blocks every event. The solution is to put your long-running code in a separate Thread. As your code is executed and obtains results, you notifiy your view (using the observer/observable pattern).As your view is notified, you update the scrollpane content.

You must also verify if you are running in the AWT-Thread or not (SwingUtilities.isEventDispatchThread()). If you are not, then you need to dispatch the update of the view in the AWT-Thread using SwingUtilities.invokeLater() because Swing is not Thread-safe.

Upvotes: 1

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