Waiting on text field input

Question

I guess I must explain what I am trying to do first I created a From with text field for accepting a name and another for password. Input must be stored in two strings username in UID and password in pass.

How can we store the values in the strings until the program ends and only then print it? No matter wherein main() I put the print statement, null values are printed even before the form opens.

Here is my code, generated by Netbeans. Check the main method.

package mypackage;

public class test extends javax.swing.JFrame {
    public test() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    private void initComponents() {

        username = new javax.swing.JTextField();
        password = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("LOGIN");

        username.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                usernameActionPerformed(evt);
            }
        });

        password.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                passwordActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(107, 107, 107)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(username, javax.swing.GroupLayout.DEFAULT_SIZE, 183, Short.MAX_VALUE)
                .addComponent(password))
                .addContainerGap(110, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(117, 117, 117)
                .addComponent(username, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(28, 28, 28)
                .addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(111, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void usernameActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_usernameActionPerformed
        uid=username.getText(); 
    }//GEN-LAST:event_usernameActionPerformed

    private void passwordActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_passwordActionPerformed
        pass=password.getText();
    }//GEN-LAST:event_passwordActionPerformed

    public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new test().setVisible(true);
            }
        });
        System.out.println(uid+" "+pass);
    }
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JTextField password;
    private javax.swing.JTextField username;
    // End of variables declaration//GEN-END:variables
    static String uid,pass;
}

Answer 1

You should add a windowListener to your frame and override windowClosing.

Here is the modified version of the init that works.

private void initComponents() {
    this.addWindowListener(new java.awt.event.WindowAdapter() {
        public void windowClosing(java.awt.event.WindowEvent windowEvent) {
                    uid=username.getText();
                    pass=password.getText();


                System.out.println(uid+" "+pass);

        }
    });

    username = new javax.swing.JTextField();
    password = new javax.swing.JTextField();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setTitle("LOGIN");

    username.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            usernameActionPerformed(evt);
        }
    });

    password.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            passwordActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(107, 107, 107)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(username, javax.swing.GroupLayout.DEFAULT_SIZE, 183, Short.MAX_VALUE)
                .addComponent(password))
            .addContainerGap(110, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(117, 117, 117)
            .addComponent(username, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(28, 28, 28)
            .addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(111, Short.MAX_VALUE))
    );

    pack();
}