Question

When I build a GUI for my Java SE app with Netbeans GUI builder, it puts all the codes in the initComponents() method which is private. I could not change it to public. So, all the components are accessible only to the class containing the UI.

I want to access those components from another class so that I can write custom event handlers and everything. Most importantly I want to separate my GUI code and non-GUI from each other.

I can copy paste the GUI code and later make them public by hand to achieve what I want. But thats a pain. I have to handcraft a portion whenever I need to re-design the UI.

What I tried to do:

I used the variable identifier to make the text box public. Now how can I access the text box from the Main class? I think I need the component generated in a public method as well.

I am new to Java. Any helps?

Here’s the sample classes:

The UI (uiFrame.java)

    /*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * uiFrame.java
 *
 * Created on Jun 3, 2010, 9:33:15 PM
 */
package barcode;

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFileChooser;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import net.sourceforge.barbecue.output.OutputException;

/**
 *
 * @author masnun
 */
public class uiFrame extends javax.swing.JFrame {

    /** Creates new form uiFrame */
    public uiFrame() {
        try {
            try {
                // Set cross-platform Java L&F (also called "Metal")
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } catch (ClassNotFoundException ex) {
                Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex);
            } catch (InstantiationException ex) {
                Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex);
            } catch (IllegalAccessException ex) {
                Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex);
            } catch (UnsupportedLookAndFeelException ex) {
                Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex);
            }
        } finally {
        }


        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">
    private void initComponents() {

        label1 = new javax.swing.JLabel();
        textBox = new javax.swing.JTextField();
        saveButton = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        label1.setFont(label1.getFont().deriveFont(label1.getFont().getStyle() | java.awt.Font.BOLD, 13));
        label1.setText("Type a text:");
        label1.setName("label1"); // NOI18N

        saveButton.setText("Save");
        saveButton.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mousePressed(java.awt.event.MouseEvent evt) {
                saveButtonMousePressed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(56, 56, 56)
                .addComponent(textBox, javax.swing.GroupLayout.PREFERRED_SIZE, 272, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(72, Short.MAX_VALUE))
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(154, Short.MAX_VALUE)
                .addComponent(saveButton, javax.swing.GroupLayout.PREFERRED_SIZE, 102, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(144, 144, 144))
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(140, Short.MAX_VALUE)
                .addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, 133, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(127, 127, 127))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(textBox, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(saveButton)
                .addContainerGap(193, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    @SuppressWarnings("static-access")
    private void saveButtonMousePressed(java.awt.event.MouseEvent evt) {                                        
        JFileChooser file = new JFileChooser();
        file.showSaveDialog(null);
        String data = file.getSelectedFile().getAbsolutePath();
        String text = textBox.getText();
        BarcodeGenerator barcodeFactory = new BarcodeGenerator();
        try {
            barcodeFactory.generateBarcode(text, data);
        } catch (OutputException ex) {
            Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex);
        }


    }                                       
    /**
     * @param args the command line arguments
     */
    // Variables declaration - do not modify
    private javax.swing.JLabel label1;
    private javax.swing.JButton saveButton;
    public javax.swing.JTextField textBox;
    // End of variables declaration
}

The Main Class (Main.java)

package barcode;


import javax.swing.JFrame;


public class Main {

    public static void main(String[] args) {

        JFrame ui = new uiFrame();
        ui.pack();
        ui.show();




    }


}

Answer 1

When you click any component in GUI Builder you can change access level.
Properties -> Code -> Variable Modifiers