jTextArea stops showing highlighting on text after losing focus

Question

When my jTextArea is in focus it allows text highlighting, but it doesn't show the text selection when it loses focus. Is it possible to continue displaying the text highlighting even if the user moves focus to another component on the related jFrame?

For better help sooner, post your code as an [SSCCE](http://www.sscce.org) that demonstrates your problem. This allows users to copy/paste and reproduce your issue. — Duncan Jones, Aug 16 '13 at 12:29
I think it is possible, but not with the standard included widgets. You'll have to write a subclass of `JTextArea` for that. — 11684, Aug 16 '13 at 12:41

score 14 · Answer 1 · answered Aug 16 '13 at 17:44

14

One simple workaround for caret selection is a simple subclassing of DefaultCaret:

textArea.setCaret(new DefaultCaret() {
   @Override
   public void setSelectionVisible(boolean visible) {
      super.setSelectionVisible(true);
   }
});

answered Aug 16 '13 at 17:44

bobby_light

726
5
14

This worked perfectly. Just needed the highlight to remain after focus was lost. – Nestor Ledon Feb 14 '16 at 20:07

score 5 · Accepted Answer · edited May 23 '17 at 10:27

but doesn't show selection on text when looses focus.

there are three ways:

use JTextPane, see Oracle tutorial
easiest in the case that we talking about selection as painting artefact from Mouse Event see my question How to override DefaultCaret#setBlinkRate(), great knowledge and answer by @camickr

enter image description here

or programatically override Highlighter

enter image description here

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Highlighter;
import javax.swing.text.JTextComponent;

public class MultiHighlight implements ActionListener {

    private JTextComponent comp;
    private String charsToHighlight;

    public MultiHighlight(JTextComponent c, String chars) {
        comp = c;
        charsToHighlight = chars;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        Highlighter h = comp.getHighlighter();
        h.removeAllHighlights();
        String text = comp.getText().toUpperCase();
        for (int j = 0; j < text.length(); j += 1) {
            char ch = text.charAt(j);
            if (charsToHighlight.indexOf(ch) >= 0) {
                try {
                    h.addHighlight(j, j + 1, DefaultHighlighter.DefaultPainter);
                } catch (BadLocationException ble) {
                }
            }
        }
    }

    public static void main(String args[]) {
        final JFrame frame = new JFrame("MultiHighlight");
        frame.add(new JTextField("Another focusable JComponents"), BorderLayout.NORTH);
        JTextArea area = new JTextArea(10, 20);
        area.setText("This is the story\nof the hare who\nlost his spectacles."
                + "\nThis is the story\nof the hare who\nlost his spectacles.");
        frame.getContentPane().add(new JScrollPane(area), BorderLayout.CENTER);
        JButton b = new JButton("Highlight All Vowels");
        b.addActionListener(new MultiHighlight(area, "aeiouAEIOU"));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(b, BorderLayout.SOUTH);
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}

jTextArea stops showing highlighting on text after losing focus

2 Answers2