Question

I have a main JFrame window with a JButton. When I click on the button a new window is opened, but when I want to close the second window, both window are closed! I want the first to opened all the time. Is there a way to only close the second window? Preciate some help! Thanks!

EDIT: I add new code to show my problem. Class GUI1 has a main frame and a button to open a second frame, GUI2, that has has a button to close GUI2 frame. It’s the closing part of GUI2 I can’t solve. The code is simple and just for testing.

GUI1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GUI1 extends JFrame implements ActionListener{
JButton btn1;
Container contentPane;
public GUI1()
{
    setTitle("GUI 1");
    setResizable(false);
    setSize(600,300);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    contentPane = getContentPane();
    contentPane.setLayout(new FlowLayout());
    btn1 = new JButton("Open GUI 2 frame");
    contentPane.add(btn1);
    btn1.setFocusable(false);
    btn1.addActionListener(this);
}
public void actionPerformed(ActionEvent event){
    if(event.getSource() == btn1)
    {
        GUI2 frame2 = new GUI2();
        frame2.setVisible(true);
    }
}
public static void main(String[] args) {
    GUI1 frame = new GUI1();
    frame.setVisible(true);
}
}

GUI2

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GUI2 extends JFrame implements ActionListener {
Container contentPane;
JButton btn2;
public GUI2()
{
    setTitle("GUI 2");
    setResizable(false);
    setSize(400,200);
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);
    contentPane = getContentPane();
    contentPane.setLayout(new FlowLayout());
    btn2 = new JButton("Close GUI 2 frame");
    contentPane.add(btn2);
    btn2.addActionListener(this);
}
public void actionPerformed(ActionEvent event){
    if(event.getSource() == btn2)
    {
        // Close GUI2 ??
    }
}
}

Answer 1

After a second read, I agree with others when they say you shouldn’t be creating and discarding JFrames (or using multiple JFrames at all). But if you really want to go that route, I’d suggest:

• Create a single JFrame, and store a reference to it somewhere your buttons can access;
• Show the frame when the “add” button is pressed;
• Use JFrame.HIDE_ON_CLOSE instead of 3 (exit on close) – don’t use magic numbers;
• Hide the frame when the other button is pressed.

Update: the steps to apply the above suggestions to your architecture are:

• add a field to your GUI1 class – private GUI2 frame – and only create it once (in the constructor of GUI1 for instance);
• in your actionPerformed, only use frame.setVisible(true) – since the frame was already created;
• I believe you could keep your DISPOSE_ON_CLOSE on GUI2, if you wanted, but HIDE_ON_CLOSE is more appropriate;
• since it’s GUI2 – the JFrame – who is implementing the action listener, you already have a reference to it: this! Use this.setVisible(false) or simply setVisible(false).