Code completion not working for RSyntaxTextArea

Question

I got RSyntaxTextArea working in JavaFX using a SwingNode, but can't seem to get code completion to work. So to remove any JavaFX related problems I implemented a Java/Swing only version with no JavaFX whatsoever. Here's that code:

package com.mystuff.swingtest;

import java.awt.*;
import javax.swing.*;
import org.fife.ui.autocomplete.*;
import org.fife.ui.rsyntaxtextarea.RSyntaxTextArea;
import org.fife.ui.rsyntaxtextarea.SyntaxConstants;
import org.fife.ui.rtextarea.RTextScrollPane;

class AutoCompleteDemo extends JFrame {

    public AutoCompleteDemo() {

        JPanel contentPane = new JPanel(new BorderLayout());
        RSyntaxTextArea textArea = new RSyntaxTextArea(20, 60);
        textArea.setSyntaxEditingStyle(SyntaxConstants.SYNTAX_STYLE_JAVA);
        textArea.setCodeFoldingEnabled(true);
        contentPane.add(new RTextScrollPane(textArea));
        
        CompletionProvider provider = createCompletionProvider();

        AutoCompletion ac = new AutoCompletion(provider);
        ac.install(textArea);

        setContentPane(contentPane);
        setTitle("AutoComplete Demo");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        pack();
        setLocationRelativeTo(null);
    }

    /**
     * Create a simple provider that adds some Java-related completions.
     */
    private CompletionProvider createCompletionProvider() {

        DefaultCompletionProvider provider = new DefaultCompletionProvider();

        // Add completions for all Java keywords. A BasicCompletion is just
        // a straightforward word completion.
        provider.addCompletion(new BasicCompletion(provider, "abstract"));
        provider.addCompletion(new BasicCompletion(provider, "assert"));
        provider.addCompletion(new BasicCompletion(provider, "break"));
        provider.addCompletion(new BasicCompletion(provider, "case"));
        // ... etc ...
        provider.addCompletion(new BasicCompletion(provider, "transient"));
        provider.addCompletion(new BasicCompletion(provider, "try"));
        provider.addCompletion(new BasicCompletion(provider, "void"));
        provider.addCompletion(new BasicCompletion(provider, "volatile"));
        provider.addCompletion(new BasicCompletion(provider, "while"));

        // Add a couple of "shorthand" completions. These completions don't
        // require the input text to be the same thing as the replacement text.
        provider.addCompletion(new ShorthandCompletion(provider, "sysout",
                "System.out.println(", "System.out.println("));
        provider.addCompletion(new ShorthandCompletion(provider, "syserr",
                "System.err.println(", "System.err.println("));

        return provider;
    }

    public static void main(String[] args) {
        // Instantiate GUI on the EDT.
        SwingUtilities.invokeLater(() -> {
            try {
                String laf = UIManager.getSystemLookAndFeelClassName();
                UIManager.setLookAndFeel(laf);
            } catch (Exception e) { /* Never happens */ }
            new AutoCompleteDemo().setVisible(true);
        });
    }
}

But when I type sysout and hit crtl+SPACE nothing happens. No popup window or anything. I checked the keystroke combination from the AutoComplete object and it says "ctrl pressed SPACE" so I know the key combination is correct.

I'm using a Mac. Tried COMMAND, ALT instead of Control, but still nothing. Any ideas?

UPDATE 1

If I press SPACE and hold down ctrl in that order, the pop up flashes on and off and when I release ctrl the pop up stays on if I catch it correctly

UPDATE 2

This led me to try changing the Trigger Key. I've not worked out the ctrl-whatever combination yet, but I tried

ac.setTriggerKey(KeyStroke.getKeyStroke('\t'));

and pressing TAB in the editor now brings up the pop-up window without the flashing. So I'll probably be able to fix the original problem if I can just find the right key combination for KeyStroke.

Answer 1

By adding a key listener it's possible to reverse engineer the Key Stroke string:

        textArea.addKeyListener(new KeyListener() {
            @Override
            public void keyTyped(java.awt.event.KeyEvent e) {
            }
            @Override
            public void keyPressed(java.awt.event.KeyEvent e) {}
            @Override
            public void keyReleased(java.awt.event.KeyEvent e) {
                System.out.println(KeyStroke.getKeyStrokeForEvent(e).toString());
            }
        });

Unfortunately ctrl+SPACE produces just released CONTROL which makes no mention of the space character. However ctrl+ENTER produces ctrl released ENTER which works a charm and is an acceptable alternative.

Still doesn't solve the ctrl+SPACE problem though !

UPDATE 2

I worked out how to get control key working, but still no space key yet:

      ac.setTriggerKey(KeyStroke.getKeyStroke("ctrl CONTROL"));

I will update later if I figure out how to get ctrl+space working.

ORIGINAL ANSWER

It's not exactly a solution, but it's a work around for now.

        ac.setTriggerKey(KeyStroke.getKeyStroke('^'));

so currently I have to press SHIFT+6 to get the pop up, which works, where I know I won't be using the ^ character in code.