Adding a JTextArea to a TabbedPane

Question

I am trying to get my JTextArea to display under all other contents of the llpPanel. My code is below with a screenshot of what my code displays. In the code you will see that I have set my dimensions for the JTextArea to (50, 50). Then in the llpPanel I have added BorderLayout.PAGE_END. I have also tried to (instead of PAGE_END) put CENTER and SOUTH. When I put SOUTH, it shows a white line at the very bottom of the program but you cannot do anything with it.

    import java.awt.BorderLayout;
    import java.awt.ComponentOrientation;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;

    import javax.swing.ButtonGroup;
    import javax.swing.JButton;
    import javax.swing.JCheckBox;
    import javax.swing.JComboBox;
    import javax.swing.JDialog;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JFrame;
    import javax.swing.JRadioButton;
    import javax.swing.JTabbedPane;
    import javax.swing.JTextArea;
    import javax.swing.JTextField;


    public class TestApplication implements ActionListener {

        public static void main(String[] args) {
        final JFrame frame = new JFrame();
        frame.setSize(1000, 1000);
        frame.setTitle("RBA Test Application");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        JButton initialize = new JButton("Initialize");         
            JButton connect = new JButton("Connect");
        JButton disconnect = new JButton("Disconnect"); 
        JButton shutdown = new JButton("Shut Down");
        JButton portsettings = new JButton("Port Settings");    
        JButton online = new JButton("Go Online");       
        JButton offline = new JButton("Go Offline");         
        JButton status = new JButton("Status"); 
        JButton reboot = new JButton("Reboot");      
        JButton account = new JButton("Account");
        JButton amount = new JButton("Amount");
        JButton reset = new JButton("Reset");
        JButton approvordecl = new JButton("Approve / Decline");

JTextArea logbox = new JTextArea(50, 50);

        JPanel testPanel = new JPanel();
        testPanel.add(button);
        testPanel.add(button2);
        testPanel.add(checkbox2);

        JPanel posPanel = new JPanel();
        posPanel.add(test);
        posPanel.add(testing);
        posPanel.add(checkbox);

        JPanel llpPanel = new JPanel();
        llpPanel.add(online);
        llpPanel.add(offline);
        llpPanel.add(status);
        llpPanel.add(reboot);
        llpPanel.add(account);
        llpPanel.add(amount);
        llpPanel.add(reset);
        llpPanel.add(approvordecl);
        llpPanel.add(logbox, BorderLayout.PAGE_END);

            JPanel buttonPanel = new JPanel();
        buttonPanel.add(initialize);
        buttonPanel.add(connect);
        buttonPanel.add(disconnect);
        buttonPanel.add(shutdown);
        buttonPanel.add(portsettings);
        frame.add(buttonPanel);
        frame.add(buttonPanel, BorderLayout.NORTH);

        JTabbedPane tabbedPane = new JTabbedPane();
        tabbedPane.addTab("LLP", null, llpPanel, "Low Level Protocol");
                tabbedPane.addTab("POS",null, posPanel, "Point Of Sale");
        tabbedPane.addTab("Test", null, testPanel, "Test");

        JPanel tabsPanel = new JPanel(new BorderLayout());
        tabsPanel.add(tabbedPane);
        frame.add(tabsPanel, BorderLayout.CENTER);  

        frame.pack();
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        // TODO Auto-generated method stub      
    }
    }

Updated code with screenshot is below...

import java.awt.BorderLayout;
import java.awt.ComponentOrientation;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JRadioButton;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;


public class TestApplication implements ActionListener {

  public static void main(String[] args) {
    final JFrame frame = new JFrame();
    frame.setSize(1000, 1000);
    frame.setTitle("RBA Test Application");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);



    JTextArea logbox = new JTextArea(50, 50);




    JButton initialize = new JButton("Initialize");

    JButton connect = new JButton("Connect");

    JButton disconnect = new JButton("Disconnect");

    JButton shutdown = new JButton("Shut Down");


    JButton portsettings = new JButton("Port Settings");


    JButton online = new JButton("Go Online");

    JButton offline = new JButton("Go Offline");

    JButton status = new JButton("Status");

    JButton reboot = new JButton("Reboot");


    JButton account = new JButton("Account");


    JButton amount = new JButton("Amount");


    JButton reset = new JButton("Reset");


    JButton approvordecl = new JButton("Approve / Decline");

    JButton test = new JButton("Test Button #1");

    JButton testing = new JButton("Test Button #2");

    JRadioButton button = new JRadioButton("Radio Button");

    JRadioButton button2 = new JRadioButton("Radio Button");

    JCheckBox checkbox = new JCheckBox("Check Box");

    JCheckBox checkbox2 = new JCheckBox("Check Box");


    JPanel newButtonPanel = new JPanel();
    newButtonPanel.add(online);
    newButtonPanel.add(offline);
    newButtonPanel.add(status);
    newButtonPanel.add(reboot);
    newButtonPanel.add(account);
    newButtonPanel.add(amount);
    newButtonPanel.add(reset);
    newButtonPanel.add(approvordecl);


    JPanel testPanel = new JPanel();
    testPanel.add(button);
    testPanel.add(button2);
    testPanel.add(checkbox2);

    JPanel posPanel = new JPanel();
    posPanel.add(test);
    posPanel.add(testing);
    posPanel.add(checkbox);

    JPanel llpPanel = new JPanel();
    llpPanel.setLayout(new BorderLayout());
    llpPanel.add(newButtonPanel);
    llpPanel.add(logbox, BorderLayout.PAGE_END);

    JPanel buttonPanel = new JPanel();
    buttonPanel.add(initialize);
    buttonPanel.add(connect);
    buttonPanel.add(disconnect);
    buttonPanel.add(shutdown);
    buttonPanel.add(portsettings);
    frame.add(buttonPanel);
    frame.add(buttonPanel, BorderLayout.NORTH);

    JTabbedPane tabbedPane = new JTabbedPane();
    tabbedPane.addTab("LLP", null, llpPanel, "Low Level Protocol");
    tabbedPane.addTab("POS",null, posPanel, "Point Of Sale");
    tabbedPane.addTab("Test", null, testPanel, "Test");

    JPanel tabsPanel = new JPanel(new BorderLayout());
    tabsPanel.add(tabbedPane);
    frame.add(tabsPanel, BorderLayout.CENTER);


    frame.pack();



}

@Override
public void actionPerformed(ActionEvent arg0) {
    // TODO Auto-generated method stub

}






}

Answer 1

Set the component's preferred size property rather than its size, and add it to BorderLayout.SOUTH. For BorderLayout layouts, the container will try to use preferred sizes for the edges (north,south,east and west) and resize the center accordingly.

A short snipped example to illustrate. The view is a panel, which will have the text area at the bottom that is 50 high. This is done by adding the JTextArea component at BorderLayout.SOUTH and set the preferred size property at Dimension(0,50). The rest of the view is filled with a panel. This panel is placed at the BorderLayout.CENTER and will be resized by the layout manager.

JPanel view = new JPanel( );
view.setSize( 800, 600 );
view.setLayout( new BorderLayout( ) );

JPanel topArea = new JPanel( );
JTextArea textArea = new JTextArea( );
textArea.setPreferredSize( new Dimension( 0, 50 ) );

view.add( topArea, BorderLayout.CENTER );
view.add( textArea, BorderLayout.SOUTH );

Answer 2

JPanels use FlowLayout by default so applying BorderLayout constraints such as PAGE_END will have no effect. You need to set the layout of the panel:

llpPanel.setLayout(new BorderLayout());

Then you will encounter the problem of components displacing themselves in the BorderLayout.CENTER position. The solution is to create another JPanel as a container for the components other than logbox on llpPanel.

JPanel newButtonPanel = new JPanel();
newButtonPanel.add(online);
...
llpPanel.add(newButtonPanel);
JScrollPane scrollPane = new JScrollPane(logbox) {
    @Override
    public java.awt.Dimension getPreferredSize() {
        return new Dimension(500, 500);
    };
};
llpPanel.add(scrollPane, BorderLayout.PAGE_END);

Use a JScrollPane rather than adding the JTextArea directly to the container.