How to auto-scroll when text is added to my JScrollPane/JArea?

Question

I have a JTextArea in a small app that shows all the exceptions e.getMessage and other things. However, the JScrollPane does not show the latest results. I have to manually scroll it so that I could see what has just happened.

I want it to be exactly like Eclipse Console

How can I set up the cursor ?

Here is my code

publiv void createGUI)( {

                JTextArea progress = new JTextArea("");

        JScrollPane jsp = new JScrollPane(progress);
        jsp.setBounds(320, 10, 280, 300); 
        j.add(jsp) ;

        JScrollBar max = jsp.getVerticalScrollBar() ;
        max.setValue(max.getMaximum() ) ;        // I tried this as suggested by Yasmani Llanes, but it did not work
...

Answer 1

Try setting the caret position at the end of the text:

progress.setCaretPosition(progress.getText().length()) 

The following example works for me:

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.SwingUtilities;


public class Test extends JFrame {
    private JTextArea txtTest;

    Test() {
        this.setSize(500, 300);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLayout(new BorderLayout());

        JScrollPane pane = new JScrollPane();
        txtTest = new JTextArea();
        pane.setViewportView(txtTest);
        this.add(pane, BorderLayout.CENTER);

        JButton btnAddText = new JButton("Add Text");
        btnAddText.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                txtTest.setText(txtTest.getText() + "\nLorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi sagittis id nibh vel rhoncus. ");

                String text = txtTest.getText();

                txtTest.setCaretPosition(text != null ? text.length() : 0);
            }
        });
        this.add(btnAddText, BorderLayout.SOUTH);

        this.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();             
            }
        });
    }
}

Answer 2

Get a hold of the scroll bar in your JScrollPane and scroll it to the bottom:

JScrollBar vertical = scrollPane.getVerticalScrollBar();
vertical.setValue(vertical.getMaximum());