Opening a JFrame

[colin shuker]

Hi, if I have a JFrame which has just been closed, using the X button at the top.

Then this JFrame object is not null and it is not visible, but when I call .setVisible(true),
it still does not appear.

Can anyone help?

Thanks

[Rob Camick]

frame.setDefaultCloseOperation(...);

Change the default to hide the frame.

[colin shuker]

I tried that, but how do I reopen it, don't want to instantiate it again.

Thanks

[Rob Camick]

Post your SSCCE showing the problem.

[colin shuker]

Heres sample code

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class ZZZ extends JFrame
{

	public SmallFrame smallFrame;

	public ZZZ()
	{
		JButton button = new JButton("Press me");
		button.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent arg0)
			{
				if(smallFrame == null)
				{
					smallFrame = new SmallFrame();
				}
				else
				{
					smallFrame.reset();
				}
				
			}
		});
		
		JPanel panel = new JPanel();
		panel.setPreferredSize(new Dimension(200,200));
		panel.add(button);
		
		this.getContentPane().add(panel);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.pack();
		this.setResizable(false);
		this.setVisible(true);
		
	}
	public static void main(String[] args)
	{
		new ZZZ();
	}
	
	
	class SmallFrame extends JFrame
	{
		public SmallFrame()
		{
			this.setSize(500,150);
			this.setVisible(true);
			
			reset();
		}
		
		public void reset()
		{
			setTitle(""+((int)(Math.random()*10000)));
		}
	}
}

When we just keep pressing the button, it updates the JFrame as expected.
But when the JFrame is closed, it is not null, and calling reset does not display it.

Can anyone get the frame to display if it is closed with the X, thanks

[Rob Camick]

but when I call .setVisible(true), it still does not appear.

I don't see where you invoke setVisible(true) again.

[colin shuker]

Oh.


I put

if 'not visible', make visible, but missed off the not ( ! )

Which is why it didn't do that, and remained invisible

Thanks