JScrollPane doesn't work properly

Question

Mr. Hovercraft Full Of Eels

I almost did what you said. MY APOLOGY it is still not showing :(

private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 760, 666);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    //frame.getContentPane().setLayout(null);
    //frame.getContentPane().setLayout();

    textArea = new JTextArea(20,20);
    textArea.setPreferredSize(new Dimension(100, 100));
    textArea.setLineWrap(true);
    JScrollPane sp = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    frame.getContentPane().add(sp);
    frame.setVisible(true);

}

---

I'm following a tutorial on YouTube using WindowBuilderPro in Eclipse. I want to create (scrollable) JTextArea using JScollPane. Even though I followed the principles, it didn't work! This little thing consumes my time so I decided to ask you guys :( KINDLY, can someone tell me why JTextArea isn't showing in JFrame .

public class ProjectGUI {

private JFrame frame;
private JTextField urls;
private JTextArea textArea;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                ProjectGUI window = new ProjectGUI();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the application.
 */
public ProjectGUI() {
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 760, 666);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(null);

    JPanel panel = new JPanel();
    panel.setBorder(new TitledBorder(null, "X.509 Extractor", TitledBorder.LEADING, TitledBorder.TOP, null, null));
    panel.setBounds(18, 16, 722, 145);
    panel.setLayout(null);
    frame.getContentPane().add(panel);

    urls = new JTextField();
    urls.setText("For multiple URLs, separate them by comma ,");
    urls.setForeground(Color.BLUE);
    urls.setBounds(59, 57, 646, 28);
    panel.add(urls);

    JButton button1 = new JButton("EXTRACT");
    button1.setBounds(303, 97, 117, 40);
    frame.setLocationRelativeTo(null);
    panel.add(button1);

    textArea = new JTextArea();
    textArea.setBounds(18, 212, 722, 414);
    textArea.setLineWrap(true);
    JScrollPane sp= new JScrollPane(textArea);
    frame.getContentPane().add(sp);
    frame.setVisible(true);

}

}

Answer 1

You're setting bounds of your JTextArea, something you should never do, and this is preventing it from growing within the JScrollPane.

Your JTextArea isn't showing because you're using a null layout and add a component without specifying its size or position, the JScrollPane.

Suggestions:

• Don't use null layout and setBounds
• Instead use an appropriate combination of JPanels using layout managers
• Never set the size or bounds of a JTextArea.
• Yes, set its rows and columns properties, that's fine.

---

Edit
Regarding your latest post, let me add, just to be clear:

• Don't set preferred size of the JTextArea
• Don't set ANY size of the JTextAera.

You will see scroll bars when the text inside of the JTextArea is larger than the bounds of the JScrollPane's viewport. For example:

import java.util.Random;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class JTextAreaTest {
   public static void main(String[] args) {
      Random random = new Random();
      StringBuilder sb = new StringBuilder();
      for (int i = 0; i < 100; i++) {
         for (int j = 0; j < 20; j++) {
            for (int k = 0; k < random.nextInt(5) + 5; k++) {
               char c = (char) ('a' + random.nextInt(26));
               sb.append(c);               
            }
            sb.append(' ');
         }
         sb.append('\n');               
      }

      JTextArea textArea = new JTextArea(15, 40);
      textArea.setText(sb.toString());
      JScrollPane scrollpane = new JScrollPane(textArea);

      JOptionPane.showMessageDialog(null, scrollpane);
   }
}