Java text with different colors

 

I want to have two lines in red and next two lines in blue color.
Is it possible ?

>> In fact, you can do it with a JTextPane, not a JTextArea.

Here is an example:
===============

import javax.swing.*;import javax.swing.text.*;import java.awt.Color;public class ColorPane extends JTextPane{ private static final long serialVersionUID = -6096151257389088124L; public void appendNaive(Color c, String s) { // naive implementation // bad: instantiates a new AttributeSet object on each call SimpleAttributeSet aset = new SimpleAttributeSet(); StyleConstants.setForeground(aset, c); int len = getText().length(); setCaretPosition(len); // place caret at the end (with no selection) setCharacterAttributes(aset, false); replaceSelection(s); // there is no selection, so inserts at caret } public void append(Color c, String s) { // better implementation--uses StyleContext StyleContext sc = StyleContext.getDefaultStyleContext(); AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY, StyleConstants.Foreground, c); int len = getDocument().getLength(); // same value as // getText().length(); setCaretPosition(len); // place caret at the end (with no selection) setCharacterAttributes(aset, false); replaceSelection(s); // there is no selection, so inserts at caret } public static void main(String argv[]) { ColorPane pane = new ColorPane(); for (int n = 1; n <= 400; n += 1) { if (isPrime(n)) { pane.append(Color.red, String.valueOf(n) + ' '); } else if (isPerfectSquare(n)) { pane.append(Color.blue, String.valueOf(n) + ' '); } else { pane.append(Color.black, String.valueOf(n) + ' '); } } JFrame f = new JFrame("ColorPane example"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setContentPane(new JScrollPane(pane)); f.setSize(600, 400); f.setVisible(true); } public static boolean isPrime(int n) { if (n < 2) return false; double max = Math.sqrt(n); for (int j = 2; j <= max; j += 1) if (n % j == 0) return false; // j is a factor return true; } public static boolean isPerfectSquare(int n) { int j = 1; while (j * j < n && j * j > 0) j += 1; return (j * j == n); }} 

All these are copied from network, not mine :)