how to insert or append new line on top of the jte

Question

how to insert or append new line on top of the jtextarea in java swing ? i want to to append jtextarea and add the new line on top of the jtextarea please help me how to do this.

Answer 1

Your best option is to directly modify the underlying Document of the JTextArea.

Here is a small demonstration of this:

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;

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

public class TestTextArea {

    private void initUI() {
        JFrame frame = new JFrame("test");
        final JTextArea textarea = new JTextArea(24, 80);
        JButton addText = new JButton("Add line");
        addText.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    textarea.getDocument().insertString(0, "New line entered on " + new Date() + "\n", null);
                } catch (BadLocationException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
        });
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new JScrollPane(textarea));
        frame.add(addText, BorderLayout.SOUTH);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new TestTextArea().initUI();
            }
        });
    }

}

Answer 2

You can do this:

textArea.setText("The new text\n" + textArea.getText());

Or, an even better solution would be this:

try {
  textArea.getDocument().insertString(0, "The new text\n", null);
} catch (BadLocationException e) {
  e.printStackTrace();
}

Answer 3

textArea.setText("this is new line" + "\n" + textArea.getText())