Overriding the default EventHandler

[JordanMartinez]

Hi Tomas,

I'm trying to create a StyleClassedTextArea that only inserts a specific list of characters (using a regex match) into its text once that text has been initialized. The following is the code I thought would achieve this:

StyleClassedTextArea scta = new StyleClassedTextArea();
scta.replaceText(0,0, "Initialized Text");
scta.setOnKeyPressed(new EventHandler<KeyEvent>() {
        @Override
        public void handle(KeyEvent event) {
                String event_text = event.getText();
                String regex_pattern = "[a-z]";

                if (event_text.matches(regex_pattern)) {
                    scta.insertText(scta.getCaretPosition(), event_text);
                }
                event.consume();
        }
});

This is what I expect:

• When I type "a" it inserts "a"
• When I type "A" it doesn't insert anything

I ran the code:

• When I type "a" it inserts "aa"
• When I type "A" it inserts "A"

What am I doing wrong? I thought my code would override the default OnKeyPressed EventHandler.

[TomasMikula]

Hi Jordan,

internally, RichTextFX listens to KEY_TYPED events to handle character input. You should add an event filter for KEY_TYPED events and consume the event if the character is illegal:

scta.addEventFilter(KeyEvent.KEY_TYPED, event -> {
    String text = event.getCharacter();
    if(!text.matches(pattern)) {
        event.consume();
    }
});