Resize a swing component based on resizing of the tool

Question

I am developing a swing UI where I need to change the size of the textArea when the tool goes full screen or someone manually does a resize..

I am using netbeans GUI builder so obviously everything is in the GroupLayout. My current GUI has lets say only the text area, I haven't added other components. So we have JFrame>>JPanel1>>jTextArea which is anchored at top and both sides so when I resize the tool it expands on horizontally to fill the whole space but since it is not anchored at the bottom so on resizing it wont fill the bottom space and I am left out with a blank space at the bottom..

I have been trying

jPanel1.addComponentListener(new ComponentAdapter() {
        @Override
        public void componentResized(ComponentEvent e) {
            }
    });

What I am trying to do here is if the size of the JPanel1 changes which will change when we resize.. it should be invoked and do something that will change the size of the textArea vertically too..

This was all to give you the base of my question. Now what I actually have is Jpanel1. At the top I have this TextArea anchored at both sides horizontally and below it I have a small JPanel2 anchored horizontally from one side to other to show some data. When I go full screen both the JPanel2 and textArea resize to go full side to side, but vertically there occours some blank space between that textArea and JPanel2. So what I was thinking is to get the height of that space between the textArea bottom and Jpanel2 top( This also I don't know how to do.) and in the method mentioned above I will do something to increase the size of the textArea with the blank space height I have found out.

Here is my code:

public class NewJFrame extends javax.swing.JFrame {

/**
 * Creates new form NewJFrame
 */
public NewJFrame() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();
    jPanel2 = new javax.swing.JPanel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder("MyBorder"));

    javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
    jPanel2.setLayout(jPanel2Layout);
    jPanel2Layout.setHorizontalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 0, Short.MAX_VALUE)
    );
    jPanel2Layout.setVerticalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 30, Short.MAX_VALUE)
    );

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
        .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 380, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(57, 57, 57)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(88, 88, 88)
            .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );

    pack();
}// </editor-fold>//GEN-END:initComponents

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new NewJFrame().setVisible(true);
        }
    });
}

// Variables declaration - do not modify//GEN-BEGIN:variables
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
// End of variables declaration//GEN-END:variables

}

but I have no idea what to do inside this. I know there are some other threads too regarding this, so please don't mark it as a duplicate. If any other solution is present, please help me find it..

I have gone through other links which shows the solution for this problem in different ways.. However I would not be able to use it because of the following constraints:
1. I am using GUI Builder of NetBeans which wont allow me to modify the code content generated when I put elements on the Panel and stuff, all that part of the code is auto generated and hence cant be modified.
2. The solutions I have gone through, all have 1 thing in common they don't have any auto generated code. They are buiding it from scratch. If I were to do it from scratch I would be able to do it but that's not the case here.

I would like the solution for exact scenario where we cant modify the generated code but the resizing can be done dynamically so that I can call some listeners and change the size..

Please bear with me on this one, I know this much of constraints put people like you in extreme situations for helping.

*"I know there are some other threads too regarding this, so please don't mark it as a duplicate."* Rather than imploring us to not close this, list the top 5 questions you saw, and explain why they did not answer your question. This helps us to better understand the constraints of your requirement, and indeed some of the answers, slightly tweaked, might answer this one. As it is, I could not be bothered trying to answer, given you'll likely say WTE "I already saw that approach, it doesn't work for me". — Andrew Thompson, Aug 27 '16 at 14:43
Don't let the GUI editor dictate your design; consider this [approach](http://stackoverflow.com/a/2561540/230513) to manage nested panels. — trashgod, Aug 27 '16 at 14:56
I know but the tool is developed this way, I have to modify it with some changes. Can't do the layout changes and all but additions of some functionalities but that's my restriction on code.. — Himanshu Gupta, Aug 27 '16 at 15:05

guleryuz · Answer 1 · 2016-08-27T14:41:48.967

it seems your issue is related with your layaoutmanager and netbeans gui biulder. you may try using another layout manager and borderlayout fits very well for your situation. using a suitable layoutmanager (eg borderlayout here) you do not need listen componentresized events.

public class Example extends JPanel {

    public Example() {
        super(new BorderLayout());
        add(new JScrollPane(new JTextArea()), BorderLayout.CENTER);
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame();
        frame.setContentPane(new Example());
        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

EDIT: using grouplayout

public class Example extends JFrame {

    private JPanel contentPane;

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater( () -> {
            Example  frame = new Example ();
            frame.setVisible(true);
        } );
    }

    public Example () {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        setContentPane(contentPane);
        JPanel panel = new JPanel();
        JPanel panel_1 = new JPanel();
        panel_1.setBorder(new TitledBorder("JPanel 2"));
        GroupLayout gl_contentPane = new GroupLayout(contentPane);
        gl_contentPane.setHorizontalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addComponent(panel))
                .addComponent(panel_1)
        );
        gl_contentPane.setVerticalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addComponent(panel)
                    .addComponent(panel_1))
        );
        panel.setLayout(new BorderLayout(0, 0));

        JTextArea textArea = new JTextArea();
        panel.add(textArea);
        contentPane.setLayout(gl_contentPane);
    }
}

This wont work for me. I have to develop it using GroupLayout only. Also I don't think yours will work too because by default when u add the JTextArea to the BroderLayout it will anchor on all sides hence when we resize it will resize on all sides. I am sorry but I would not be able to use another Layout because then I would have to build everything from scratch again.. — Himanshu Gupta, Aug 27 '16 at 14:17
guleryuz Thanks that works.. But I will still wont be able to use it because this part is building from scratch. Please see the update that I have mentioned the code is autogenerated and hence cant be modified. I can do the changes from the properties that comes when we use the GUI Builder but that it. You really are helpful man.. thanks I appreciate it. — Himanshu Gupta, Aug 27 '16 at 15:12

Resize a swing component based on resizing of the tool

1 Answers1