dynamically adding checkboxes in java swing

Question

Reference to the given code..i can access the print statement inside the if statement in for-loop(inside try-catch block) but the checkboxes are not adding. I am using the revalidating and repaint function but still its not working. The for loop inside the try-catch block is running except for the adding jscrollpane. Where am i wrong?

 /*
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 * and open the template in the editor.
 */
package com.anurag;
import com.anurag.HttpURLConnectionExample;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import jxl.Cell;
import jxl.Sheet;
import jxl.Workbook;

/**
 *
 * @author Anurag
 */
public class MainGui {

   static JFrame frame = new JFrame("Rest Testing");

    public static void main(String args[]) {

frame.setLayout(new FlowLayout());
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  final JTextField path = new JTextField("getresponse.xls");
   frame.add(path);


  JButton upload = new JButton("Upload");
    frame.add(upload);

    upload.addActionListener(new ActionListener(){ 
        @Override
        public void actionPerformed(ActionEvent arg0) {



             JScrollPane jscrlpLabel = new JScrollPane(new JLabel(
             "<HTML>A<br>B<br>C<br>D<br>E<br>F<br>G<br>H<br></HTML>"));
             jscrlpLabel.setPreferredSize(new Dimension(200, 100));
             frame.add(jscrlpLabel);
             frame.revalidate();
             frame.repaint();


       try{    
             System.out.println(path.getText());
             HttpURLConnectionExample http  = new HttpURLConnectionExample();
             int noOfRows = http.setPath(path.getText());

              Workbook workbook = Workbook.getWorkbook(new File(path.getText()));
              Sheet sheet = workbook.getSheet(0);

             Cell cell= sheet.findCell("S. No.");

             int col=cell.getColumn();
             int row=cell.getRow();
             row=row+2;
             //System.out.println("row="+row+"col="+col);
             for(int i=row;i<noOfRows;i++,row++)
             {   
                 int p=http.readFile(col,row);
                 if(p==1){

                      JCheckBox cb = new JCheckBox("CheckBox");
                      JScrollPane jscrlp = new JScrollPane(cb);
                      jscrlp.setPreferredSize(new Dimension(140, 95));
                      frame.add(jscrlp);
                      frame.revalidate();
                     frame.repaint();



                     System.out.println("Checkbox created");
                  }  
                 else if(p==2){
                     JCheckBox cb1 = new JCheckBox("CheckBox ");
                     Box box = Box.createVerticalBox();
                     box.add(cb1);
                     JScrollPane jScrollPane1 = new JScrollPane(box);
                     jScrollPane1.setPreferredSize(new Dimension(140, 95));
                     frame.add(jScrollPane1);
                     frame.revalidate();
                     frame.repaint();

                     System.out.println("Checkbox created with textfield");
                 }
             }
             http.getData();

        }catch(Exception e){System.out.println("Exception is "+e);}

            }
    });









 //JOptionPane.showMessageDialog(null, "Done", "Alert", WIDTH);
 JCheckBox a = new JCheckBox("A");
JCheckBox b = new JCheckBox("B");
JLabel label = new JLabel("Option");

Box box = Box.createVerticalBox();
box.add(label);
box.add(a);
box.add(b);

JScrollPane jscrlpBox = new JScrollPane(box);
jscrlpBox.setPreferredSize(new Dimension(240, 150));
//f.add(jscrlpLabel);
frame.add(jscrlpBox);

frame.setVisible(true);
}

}

`Box` is not meant as a displayable component. You should be adding your checkboxes to a common component (say a `JPanel`), which is then wrapped in `JScrollPane` — MadProgrammer, Jul 08 '15 at 05:25
Also, there's not point in calling `revaldiate` and `repaint` each time you add a component inside the loop as the UI can't be updated until you exit the `actionPerformed` method — MadProgrammer, Jul 08 '15 at 05:30
@MadProgrammer Can you show me the code snippet..that would be helpful for me. — A-G, Jul 08 '15 at 05:52
I recommend reading a good tutorial or three, which would help understand any code snippet I'm likely to throw at you ;) — MadProgrammer, Jul 08 '15 at 06:46

score 2 · Answer 1 · edited May 23 '17 at 10:26

Start by having a read through Creating a GUI With JFC/Swing, Laying Out Components Within a Container, Concurrency in Swing and How to Use Scroll Panes

Box is not really a "visible" component, it's meant as a feature to be used with BoxLayout
You're adding multiple JScrollPanes to the single view, which kind of feels weird to me
Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?
You're updating the UI from within the Event Dispatching Thread, but the process by which you're making your decisions may take time to run, this could make the UI look like it's doing nothing until the actionPerformed method exist
There's little point in calling revaldiate all the time, leave it until you have finished updating the whole UI, it will provide better performance in the long run

Start by creating a JPanel which you then wrap a JScrollPane around, add the JScrollPane to the base UI

As required, add and remove components from this JPanel, for example...

Example

public class MainGui {

    public static void main(String args[]) {
        new MainGui();
    }

    private JFrame frame = new JFrame("Rest Testing");
    private JPanel checkboxes;

    public MainGui() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                frame.setSize(500, 500);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                final JTextField path = new JTextField("getresponse.xls");

                JPanel fields = new JPanel();
                fields.add(path);

                JButton upload = new JButton("Upload");
                fields.add(upload);

                frame.add(fields, BorderLayout.NORTH);

                checkboxes = new JPanel(new GridBagLayout());
                JScrollPane scrollPane = new JScrollPane(checkboxes);

                frame.add(scrollPane);

                upload.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent arg0) {

                        GridBagConstraints gbc = new GridBagConstraints();
                        gbc.gridwidth = GridBagConstraints.REMAINDER;
                        gbc.anchor = GridBagConstraints.WEST;
                        gbc.weightx = 1;

                        checkboxes.add(new JLabel("<HTML>A<br>B<br>C<br>D<br>E<br>F<br>G<br>H<br></HTML>"), gbc);

                        try {
                            int noOfRows = 100;
                            for (int row = 0; row < noOfRows; row++, row++) {
                                int p = (int) ((Math.random() * 2) + 1);
                                System.out.println(p);
                                if (p == 1) {

                                    JCheckBox cb = new JCheckBox("CheckBox");
                                    checkboxes.add(cb, gbc);

                                } else if (p == 2) {

                                    JCheckBox cb1 = new JCheckBox("CheckBox ");
                                    JPanel stuff = new JPanel();
                                    stuff.add(cb1);
                                    stuff.add(new JTextField(10));
                                    checkboxes.add(stuff, gbc);

                                }
                            }

                        } catch (Exception e) {
                            System.out.println("Exception is " + e);
                        }

                        checkboxes.revalidate();
                        checkboxes.repaint();
                    }
                });

                //JOptionPane.showMessageDialog(null, "Done", "Alert", WIDTH);
                JCheckBox a = new JCheckBox("A");
                JCheckBox b = new JCheckBox("B");
                JLabel label = new JLabel("Option");

                JPanel stuff = new JPanel();
                stuff.add(label);
                stuff.add(a);
                stuff.add(b);
                GridBagConstraints gbc = new GridBagConstraints();
                gbc.gridwidth = GridBagConstraints.REMAINDER;
                gbc.anchor = GridBagConstraints.WEST;
                gbc.weightx = 1;
                checkboxes.add(stuff, gbc);

                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

            }
        });
    }

}

Now, I'm not 100% sure, but you might find using a JTable produces the look you're after. How to Use Tables

Thanks:) It helps a lot @MadProgrammer – A-G Jul 15 '15 at 07:25 — A-G, Jul 15 '15 at 07:25

score 0 · Answer 2 · edited May 23 '17 at 12:29

0

You can't add the checkboxes directly to the scroll pane, you need to make a list model. You will need a Scroll Pane, a list renderer, a model, and a custom JCheckboxList class. See the following questions:

How do I make a list with checkboxes in Java Swing?

Also, you might run into a problem that I did where the JScrollPane's viewport:

Components in JList are Hidden by White Square Thing Until Clicked

edited May 23 '17 at 12:29

Community

1
1

answered Jul 08 '15 at 05:32

ColonelHedgehog

438
3
18

You can add A `JCheckBox` to a `JScrollPane`, kind of pointless though. You could also add `JCheckBox`s to a `JPanel` and then wrap the `JPanel` in a `JScrollPane`, but that comes down to trying to figure out what the OP hopes to achieve though ;) – MadProgrammer Jul 08 '15 at 06:48

dynamically adding checkboxes in java swing

2 Answers2