why are my buttons not showing up?

Question

I am trying to create an array of buttons as a simulation of a seatingChart, but the buttons wont show up on the screen only the frame shows up. what am I doing wrong?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class guiCreator extends JFrame
{
    public guiCreator()
    {
        setTitle("Seats");
        setSize(500, 600);
        addWindowListener(new WindowAdapter()
             {  public void windowClosing(WindowEvent e)
                {  System.exit(0);
                }
             } );

          Container contentPane = getContentPane();
          contentPane.add(new seatingPanel());
        setVisible(true);  
    }

}

class seatingPanel extends JPanel implements ActionListener
{
    public seatingPanel()
    {
        setLayout(new BorderLayout());

        JPanel panel4seating = new JPanel();//creating a grid panel
        panel4seating.setLayout(new GridLayout(4, 10));//setting the layout of the grid panel

        JButton [] seats = new JButton [40]; //creating a pointer to the buttonsArray
        for (int i = 0; i < 40; i++)
        {
            seats[i] = new JButton();//creating the buttons
            seats[i].addActionListener(this);
            panel4seating.add(seats[i]);
        }
    }

    @Override
    public void actionPerformed(ActionEvent evt) 
    {


    }
    //main
    guiCreator flightSeats = new guiCreator();

score 3 · Answer 1 · answered Jun 11 '11 at 10:58

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GuiCreator extends JFrame
{
    public GuiCreator()
    {
        super("Seats");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Container contentPane = getContentPane();
        contentPane.add(new SeatingPanel());

        pack();    

        setVisible(true);
    }

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

class SeatingPanel extends JPanel
{
    public SeatingPanel()
    {
        super(new BorderLayout());

        JPanel panel4seating = new JPanel();//creating a grid panel
        panel4seating.setLayout(new GridLayout(4, 10));//setting the layout of the grid panel

        JButton [] seats = new JButton [40]; //creating a pointer to the buttonsArray
        for (int i = 0; i < 40; i++)
        {
            seats[i] = new JButton();//creating the buttons
            //better to set the preferred size of the button
            seats[i].setPreferredSize(new Dimension(50,25));
            panel4seating.add(seats[i]);
        }

        add(panel4seating, BorderLayout.CENTER);
    }
}

GUIs should be created on the EDT (my laziness).
Use camel case for names.
It is not necessary to extend either JFrame or JPanel in this instance.

The other (undocumented) changes to the source are improvements. If you have questions on any part of the changes, ask.

thank you very much it works? can you check if I am doing the action listener correct? im trying to create a seating chart and whenever that button is clicked an action is performed. I want to refer to the button using its index. and if I add another JPanel with a different set of buttons will I use the same actionListener — dave, Jun 11 '11 at 11:08

score 1 · Accepted Answer · answered Jun 11 '11 at 10:47

You're creating a new JPanel in seatingPanel's constructor, but you're not adding it to the seatingPanel itself, so it won't show up at all.

Try adding it to the seatingPanel's layout.

(Or do away with that sub-panel entirely - set the grid layout and and the buttons directly to your seatingPanel.)

why are my buttons not showing up?

2 Answers2

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