Disposing JFrame with addActionListener using a JButton

Question

I have been trying to solve ths problem for the past 3 days :/

I have a class Login() which creates a JFrame-object

Another class named LoginTab() which has a constructor with a JFrame-object as parameter.

I want to dispose the JFrame with a Button in the LoginTab() class. But the addActionListener does not accept the JFrame-object and I don't know why :(

The Code of the LoginTab():

package tabs;

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Locale;
import java.util.ResourceBundle;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;

import abstractClasses.JTextFieldImmo;
import abstractClasses.ValidateInput;

import programs.MySQL;
import windows.ButtonPanel;
import windows.UserDetails;

public class LoginTab extends ValidateInput {

/**
 * 
 */
private static final long serialVersionUID = 1L;

static Locale locale = new Locale("de");
static ResourceBundle r = ResourceBundle.getBundle("Strings", locale);

// static Connection con = null;
static Statement stnt = null;
static ResultSet rs = null;

public LoginTab(JFrame window) {
    panelMethod(window);
}

// LOGIN ITEMS
JLabel usernameLbl = new JLabel(r.getString("username"));
JLabel passwordLbl = new JLabel(r.getString("password"));
JTextFieldImmo usernameFld = new JTextFieldImmo(10);
JPasswordField passwordFld = new JPasswordField(10);
JButton loginBtn = new JButton(r.getString("login"));
JButton registerUserBtn = new JButton("Neuer Benutzer"); // TODO String
                                                            // einfügen

public void panelMethod(JFrame window) {

    this.setLayout(new GridBagLayout());

    GridBagConstraints c = new GridBagConstraints();

    // Insets
    c.insets = new Insets(4, 5, 0, 0);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 0;
    this.add(usernameLbl, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 0;
    this.add(usernameFld, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 1;
    this.add(passwordLbl, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 1;
    this.add(passwordFld, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 2;
    this.add(loginBtn, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 2;
    this.add(registerUserBtn, c);

    // Actions Listener


    loginBtn.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                MySQL.connect();
                String username = usernameFld.getText().trim();
                String password = String.valueOf(passwordFld.getPassword())
                        .trim();

                String sql = "SELECT username,password from per_user where username = '"
                        + username + "'and password = '" + password + "'";
                stnt = MySQL.getCon().createStatement();
                rs = stnt.executeQuery(sql);

                int count = 0;

                while (rs.next()) {
                    count = count + 1;
                }

                if (count == 1) {
                    JOptionPane.showMessageDialog(null, "User Found, Access Granded!"); //TODO String
                    //window.setVisible(false);
                    //window.dispose();
                    new ButtonPanel();
                } else if (count > 1) {
                    JOptionPane.showMessageDialog(null,
                            "Duplicate User, Access Denied!"); // TODO String einfügen
                } else {
                    JOptionPane.showMessageDialog(null, "User not Found"); // TODO String einfügen
                }

            } catch (Exception e1) {
                // JOptionPane.showMessageDialog(null,
                // "Es konnte keine Verbindung zum MySQL Server hergestellt werden.");
                e1.printStackTrace();
            }

        }
    });

    registerUserBtn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            new UserDetails();
        }
    });

    passwordFld.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            loginBtn.doClick();

        }
    });
}
}        

Answer 1

To call a method on another object, you need a reference to that other object. One problem I see with your code is that nowhere (that I can see anyway) is there a reference to your currently visualized Login object. To solve the problem, you will need to gain this reference, perhaps via a constructor parameter or a setter method, and then close the JFrame.

As an aside, it is somewhat unusual to have to close a JFrame in this fashion mid-program. Are you sure that you shouldn't instead be using a modal dialog such as a JDialog here in place of a JFrame?

Also, your code shows many GUI components, but where are they added to a top-level window and displayed?

---

Edit
Also note that you can get the enclosing top level Window via the SwingUtilities method:

SwingUtilities.getWindowAncestor(...);

Answer 2

Check out the ExitAction from Closing an Application . The ExitAction class will find the active window and then send a close request to that window. So the class can be used to close any window.

Answer 3

You need to make the reference to window as final in order to access it inside anonymous class ActionListener :

public void panelMethod(final JFrame window) {
    // obmitted code
}

And then:

loginBtn.addActionListener(new ActionListener() {
    // obmitted coce

    if (count == 1) {
    JOptionPane.showMessageDialog(null, "User Found, Access Granded!"); //TODO String
    window.setVisible(false);
    window.dispose();
    new ButtonPanel();
    }

    // ...
}

I would suggest you to read Core Java Volumn I in order to know the good approach to develop Java application as well as using Swing components.