SWT Keylistener is not triggered

Question

I have a SWT GUI, containing different elements (Text, Buttons, Labels...) which are themselves in different Composites.

I would like to make the navigation easier using some keybindings such as "Alt+c" to call the Cancel Button, "Alt+f" to call the finish button etc... When using a KeyListener on a specific component, the listener is triggered, but it implies that the component has the focus (and this is not very convenient !).

So I tried to register the listener on the shell itself, but the result is the same and nothing is triggered.

How should I proceed in order to get my listener triggered no matters what element is currently focused ?

Any hint would be appreciated. Thanks for reading.

Edit

Regarding the comments, I tried to add the keylistener recursively to all the composites of the GUI, and it's working. However, I guess there is probably a "clever" way to do it.

The reason why your key event listeners aren't called is described here: http://stackoverflow.com/questions/7225756/swt-event-propagation — Rüdiger Herrmann, Jun 03 '16 at 09:56
I was thinking to something similar at first, but I thought it would be too messy. I guess this is what I will try — MedAl, Jun 03 '16 at 12:31

score 2 · Answer 1 · answered Jun 03 '16 at 09:53

2

You can use the Display addFilter or addListener methods to add a listener which is always called.

Display.getDefault().addListener(SWT.KeyDown, new Listener() {
  @Override
  public void handleEvent(final Event event) {
    // TODO handle event
  }
});

These listeners use the lower level Listener interface rather than KeyListener.

addFilter is similar to addListener but is called earlier and can change the event.

answered Jun 03 '16 at 09:53

greg-449

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Unfortunately, it doesn't seem to work in my case. The event is still not caught ... Should I precise that the swt window is generated by a plugin in Eclipse ? – MedAl Jun 03 '16 at 12:31
If this is an Eclipse plugin you should say so as that is substantially different. You should look at the `org.eclipse.ui.bindings` extension point. But it depends a lot on exactly where these controls are. You need to show us code. – greg-449 Jun 03 '16 at 12:47
Sorry for the lack of precision. I will have a look to that extension – MedAl Jun 03 '16 at 12:49

score 0 · Answer 2 · answered Jan 09 '19 at 18:36

The easiest way is to add a event filter to the display:

Here is an example I use to activate a search field when a user types command-F in our main application window.

    Display.getCurrent().addFilter(SWT.KeyDown, event -> {

        // Only respond to key events for our shell.
        if (getShell().equals(Display.getCurrent().getActiveShell())) {
            // Activate the focus for our search widget when user types 'f'
            // (control-f, command-f, or just f)
            if (event.keyCode == 'f') {
                if (!searchField.isFocusControl()) {
                    searchField.setFocus();
                }
            }
        }
    });

SWT Keylistener is not triggered

Edit

2 Answers2