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

Question

Problem 1: BY using defaulthighlighter, I can make the focused lines change to blue. Now I want to change it to other colors. Do anyone know how to change this param

Answer 1

To set the selection background color, use setSelectionColor (illustrated below but not used).

I don't really understand what you're saying with it always appears at the bottom of the window. I want to have it at the top but I am guessing (and I may be wrong here) that your textarea is in a scrollpane and that by highlighting the text it scrolls to the end of your selection, so I suggest to set the caret position after highlighting the text.

Here is a sample of what I understood. Let me know if this is not what you're looking for:

import java.awt.Color;
import java.net.MalformedURLException;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;

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\n");
        textArea.setSelectionColor(Color.RED);
        frame.add(pane);
        frame.setSize(300, 120);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        String turnToString = "Something else.\nA second line\na third line"
                + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla";
        final int pos = textArea.getText().indexOf(turnToString);
        textArea.getHighlighter().addHighlight(pos,
                pos + turnToString.length(),
                new DefaultHighlighter.DefaultHighlightPainter(Color.yellow));
        textArea.scrollRectToVisible(new Rectangle(0, 0, pane.getViewport().getWidth(), pane.getViewport().getHeight()));
            SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        textArea.setCaretPosition(pos);
                    }
            });
    }
}