Close Gps on BoxLayout

Question

I have created a setup of buttons using Box.

The problem is there are gaps between all the buttons.

Below is an MCVE version of my code. What I want to achieve is that the buttons "ONE" and "TWO" are touching side by side, with no gap, and buttons "ONE and "ONE" are touching top to bottom with no gap, and for this to continue throughout the setup.

I have read about glue and have tried to use it, but I have not been able to work it out. I am not able to use another layout other than Box as it will not fit in with the rest of my project.

public class Customers {

     public static JFrame frame = new JFrame();

     public static void frameGui(JPanel panel, String name){             
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);            
            frame.setContentPane(panel);    
            frame.setSize(1200,500);         
            frame.setVisible(true);
     }

     public static void ScrollCustomersGui(){               
            Box box = Box.createVerticalBox();              
            box.add(customersTableHeadings(box));
            box.add(customersTableHeadings(box));
            box.add(customersTableHeadings(box));
            box.add(customersTableHeadings(box));               
            JScrollPane scroll = new JScrollPane(box);              
            JPanel All = new JPanel(new BorderLayout());
            All.add(scroll);                
            frameGui(All, "Customers");
        }       

    public static JPanel customersTableHeadings(Box panel){                  
         Font font = new Font("Courier", Font.BOLD,12);         
         JPanel customersTable = new JPanel();           
         JButton custid = new JButton("ONE");            
         JButton surname = new JButton("TWO");          
         customersTable.add(custid);
         customersTable.add(surname);            
         return customersTable;         
    }
}

Answer 1

BoxLayout is designed to distribute unused space among components; struts, glue and filler won't change this. You can use the approach suggested here and here to alter the preferred size of the enclosing scroll pane. More generally, you can implement the scrollable interface. In addition, Swing GUI objects should be constructed and manipulated only on the event dispatch thread.

import java.awt.Dimension;
import java.awt.EventQueue;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

/** @se https://stackoverflow.com/a/26829171/230513 */
public class Customers {

    private static final int N = 16;

    private void display() {
        Box box = Box.createVerticalBox();
        for (int i = 0; i < N; i++) {
            box.add(customersTableHeadings());
        }

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new JScrollPane(box) {
            int w = box.getPreferredSize().width;
            int h = box.getPreferredSize().height;

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(9 * w / 8, h / 3);
            }
        });
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private JPanel customersTableHeadings() {
        JPanel customersTable = new JPanel();
        JButton custid = new JButton("ONE");
        JButton surname = new JButton("TWO");
        customersTable.add(custid);
        customersTable.add(surname);
        return customersTable;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            new Customers().display();
        });
    }
}

Answer 2

I found the answer myself. By adding the horizontal and vertical inside the same loop, and by enclosing this in a JApplet it closes the gap.

Below is a full working version of the code:

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import javax.swing.Box;
import javax.swing.JApplet;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;


public class Box1 extends JApplet {

    public void init() {

    Box bv = Box.createVerticalBox();

    box(bv);    

    JScrollPane scroll = new JScrollPane(bv);

    JPanel All = new JPanel(new BorderLayout());
    All.add(scroll);

    Container cp = getContentPane();
    cp.add(All);
  }


  public static void main(String[] args) {
    frameGui(new Box1(), "Customers");
  }

  public static void frameGui (JApplet applet, String name) {
      JFrame frame = new JFrame();
    frame.getContentPane().removeAll(); 
    frame.setTitle(name);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
    frame.getContentPane().add(applet);
    frame.setSize(1200, 500);
    applet.init();
    applet.start();
    frame.setVisible(true);

  }



  public static Box box(Box boxvert){

      for (int i = 0; i < 50; i++){ 

             JTextField one = new JTextField("ONE");
             one.setMaximumSize(new Dimension (150,20));

             JTextField two = new JTextField("TWO");
             two.setMaximumSize(new Dimension (150,20));            

             Box horizontalBox = Box.createHorizontalBox();

             horizontalBox.add(one);
             horizontalBox.add(two);          

             boxvert.add(horizontalBox);

        }

      return boxvert;

  }



}