How to change highlighting color in Java Swing TextArea? And also, change the beginning of text corresponding to the highlighting location

by

You can achieve this, though not directly, since you have to save the reference to the Highlight that you had added to the said line, hence you have to traverse through all the Highlights to remove the one you want, have a look at the program attached, might be this will help you to attain what you so desire :

LATEST EDIT : NEW CODE, REMOVED SOME BUGS AND SEEMS LIKE ADDED THE DESIRED FUNCTIONALITY RELATED TO SETTING CARET POSITION

import java.awt.*;
import java.awt.event.*;
import java.util.Map;
import java.util.HashMap;
import javax.swing.*;
import javax.swing.text.*;

public class TextHighlight
{
    private JTextArea tarea;
    private JComboBox cbox;
    private JTextField lineField;
    private String[] colourNames = {"RED", "ORANGE", "CYAN"};

    private Highlighter.HighlightPainter redPainter;
    private Highlighter.HighlightPainter orangePainter;
    private Highlighter.HighlightPainter cyanPainter;   

    private int firstUpdateIndex;
    private int counter;

    private Map<Integer, Highlighter.Highlight> highlights = new HashMap<Integer, Highlighter.Highlight>();

    public TextHighlight()
    {
        redPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.RED);
        orangePainter = new DefaultHighlighter.DefaultHighlightPainter(Color.ORANGE);
        cyanPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.CYAN);

        firstUpdateIndex = -1;
        counter = 0;
    }

    private void createAndDisplayGUI()
    {
        final JFrame frame = new JFrame("Text HIGHLIGHT");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setBorder(BorderFactory.createTitledBorder(
                BorderFactory.createEmptyBorder(5, 5, 5, 5), "Highlighter JTextArea"));

        tarea = new JTextArea(10, 10);
        JScrollPane scrollPane = new JScrollPane(tarea);
        contentPane.add(scrollPane);

        JButton remHighButton = new JButton("REMOVE HIGHLIGHT");
        remHighButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String input = JOptionPane.showInputDialog(frame, "Please Enter Start Index : "
                                                        , "Highlighting Options : "
                                                        , JOptionPane.PLAIN_MESSAGE);

                if (input != null && (highlights.size() > 0))
                {               
                    int startIndex = Integer.parseInt(input.trim());
                    Highlighter highlighter = tarea.getHighlighter();
                    highlighter.removeHighlight(highlights.get(startIndex));
                    tarea.setCaretPosition(startIndex);
                    tarea.requestFocusInWindow();
                    highlights.remove(startIndex);
                }
            }
        });

        JButton button = new JButton("HIGHLIGHT TEXT");
        button.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String text = null;
                text = tarea.getSelectedText();
                if (text != null && text.length() > 0)
                {
                    int startIndex = tarea.getText().indexOf(text);
                    int endIndex = startIndex + text.length();
                    Highlighter highlighter = tarea.getHighlighter();

                    int selection = JOptionPane.showConfirmDialog(
                                            frame, getOptionPanel(), "Highlight Colour : "
                                                , JOptionPane.OK_CANCEL_OPTION
                                                , JOptionPane.PLAIN_MESSAGE);

                    System.out.println("TEXT : " + text);
                    System.out.println("START INDEX : " + startIndex);
                    System.out.println("END INDEX : " + endIndex);

                    if (selection == JOptionPane.OK_OPTION)
                    {
                        String colour = (String) cbox.getSelectedItem();
                        try
                        {
                            if (colour == colourNames[0])
                            {
                                System.out.println("Colour Selected : " + colour);
                                highlighter.addHighlight(startIndex, endIndex, redPainter);
                            }
                            else if (colour == colourNames[1])
                            {
                                System.out.println("Colour Selected : " + colour);
                                highlighter.addHighlight(startIndex, endIndex, orangePainter);
                            }
                            else if (colour == colourNames[2])
                            {
                                System.out.println("Colour Selected : " + colour);
                                highlighter.addHighlight(startIndex, endIndex, cyanPainter);
                            }
                            Highlighter.Highlight[] highlightIndex = highlighter.getHighlights();
                            System.out.println("Lengh of Highlights used : " + highlightIndex.length);
                            highlights.put(startIndex, highlightIndex[highlightIndex.length - 1]);
                        }
                        catch(BadLocationException ble)
                        {
                            ble.printStackTrace();
                        }
                    }
                    else if (selection == JOptionPane.CANCEL_OPTION)
                    {
                        System.out.println("CANCEL BUTTON PRESSED.");
                    }
                    else if (selection == JOptionPane.CLOSED_OPTION)
                    {
                        System.out.println("JOPTIONPANE CLOSED DELIBERATELY.");
                    }                   
                }
            }
        });

        frame.add(remHighButton, BorderLayout.PAGE_START);
        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(button, BorderLayout.PAGE_END);

        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JPanel getOptionPanel()
    {
        JPanel panel = new JPanel();
        panel.setBorder(BorderFactory.createTitledBorder(
                        BorderFactory.createLineBorder(Color.DARK_GRAY, 2), "COLOUR SELECTION"));
        panel.setLayout(new GridLayout(0, 2, 5, 5));

        JLabel colourLabel = new JLabel("Select One Colour : ");
        cbox = new JComboBox(colourNames);

        panel.add(colourLabel);
        panel.add(cbox);

        return panel;
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TextHighlight().createAndDisplayGUI();
            }
        });
    }
}

OUTPUT :

BEGIN : AT START

HIGHLIGHT FIRST LINE FIRST LINE SECOND SECOND LINE

REMOVED HIGHLIGHT AFTER

HIGHLIGHTING THE SAME LINE WITH DIFFERENT COLOUR HIGHLIGHT AGAIN

LATEST EDIT in lines with the SAMPLE CODE in the QUESTION

import java.awt.*;
import java.net.MalformedURLException;

import javax.swing.*;
import javax.swing.text.*;

public class Test {
    public static void main(final String[] args) throws MalformedURLException {
        SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            try {
                init();
            } catch (BadLocationException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });
}

private static void init() throws BadLocationException {
    JFrame frame = new JFrame();
    final JTextArea textArea = new JTextArea();
    JScrollPane pane = new JScrollPane(textArea);
    textArea.setText("Something. Something else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Samething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Sbmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Scmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Sdmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Semething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Sfmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Sgmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n");
    textArea.setSelectionColor(Color.RED);
    frame.add(pane);
    frame.setSize(300, 120);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

    String turnToString2 = "Sdmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla";
    int pos2 = textArea.getText().indexOf(turnToString2);
    Rectangle startIndex = textArea.modelToView(pos2);
    textArea.getHighlighter().addHighlight(pos2,
            pos2 + turnToString2.length(),
            new DefaultHighlighter.DefaultHighlightPainter(Color.yellow));    
    int y = startIndex.y + (pane.getHeight() - 10);
    System.out.println("Pane Height : " + pane.getHeight());
    System.out.println("X : " + startIndex.x);
    System.out.println("Y : " + y);
    System.out.println("Y (pos2) : " + startIndex.y);
    textArea.setCaretPosition(textArea.viewToModel(new Point(startIndex.x, y)));
    pane.scrollRectToVisible(new Rectangle(startIndex.x, y));
    }
}

Here is the OUTPUT :

TOP RIGHT

More Related Contents:

  1. JTextArea content is not printing in printer fully [closed]
  2. How to change text color in the JTextArea?
  3. How to set output stream to TextArea
  4. How to calculate the number of rows (and columns in each row) a text takes in a JTextArea?
  5. Text-mouseover popups over a Swing JTextArea?
  6. How to set AUTO-SCROLLING of JTextArea in Java GUI?
  7. Add a new line to the end of a JtextArea
  8. Get a key from JTextArea
  9. Centering Text in a JTextArea or JTextPane – Horizontal Text Alignment
  10. Java – Scroll to specific text inside JTextArea
  11. Internal padding for JTextArea with background Image
  12. ActionListener for a specific text inside a JTextArea?
  13. How to set the orientation of JTextArea from right to left (inside JOptionPane)
  14. jTextArea as IO console
  15. JTextArea appending problems
  16. Make JScrollPane control multiple components
  17. How to display bold text in only parts of JTextArea?
  18. Set color of JTable row at runtime
  19. Update JLabel every X seconds from ArrayList – Java
  20. rotating coordinate plane for data and text in Java
  21. How to allow introducing only digits in jTextField?
  22. Java GUI frameworks. What to choose? Swing, SWT, AWT, SwingX, JGoodies, JavaFX, Apache Pivot? [closed]
  23. How do I make a list with checkboxes in Java Swing?
  24. Zoom box for area around mouse location on screen [closed]
  25. Adding multiple JProgressBar to TableColumn of JTable
  26. Saving a Java 2d graphics image as .png file
  27. Java Swing Timer and Animation: how to put it together
  28. How can I set the priority mouse listener
  29. Multi-line tooltips in Java?
  30. about drawing a Polygon in java

Leave a Comment