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I have the code to do this, but I can't do it. I made something similar and worked without problem ( and asked here too) . Basically I am trying to pass the username that I enter into my textbox to a label from my otherJFrame ( I know it's not good practice to have 2 JFrames ).

The code where I try to parse my data is supposed to happen here :

if( rs.next() ) 
{
     JOptionPane.showMessageDialog(null, "Successfully Logged In", "Success", JOptionPane.INFORMATION_MESSAGE);

this.setVisible(false);
new FrmMain2(username).setVisible(true);
}

This is the whole code from the 1'st frame

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package mysqltryouts;

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

/**
 *
 * @author ExtremeSwat
 */





public class login_panel extends javax.swing.JFrame {


  private Connection connect = null;
  private Statement statement = null;
  private PreparedStatement preparedStatement = null;
  private ResultSet resultSet = null;




  public void readDataBase() throws Exception
  {

       String username = jTextField1.getText();

      String password = jPasswordField1.getText();

//    System.out.println(username);
//    System.out.println(password);
//    System.out.println("test");

      //---------------------

//      String databaseUsername = "";
//      String databasePassword = "";

    try {
      // this will load the MySQL driver, each DB has its own driver

      Class.forName("com.mysql.jdbc.Driver");

      // setup the connection with the DB.

      connect = DriverManager
          .getConnection("jdbc:mysql://localhost/cards?"
              + "user=root&password=password");





     //String sqlQuery = "select count(*) > 0 as match_found FROM username WHERE username = ? and password = MD5(?)";
      String sqlQuery = "SELECT * FROM username WHERE username = ? and password = MD5(?)";
       // String sqlQuery = "select count(*) > 0 as cnt FROM username WHERE username = ? and password = MD5(?)";

      PreparedStatement pst = connect.prepareStatement( sqlQuery );
pst.setString( 1, username );
pst.setString( 2, password );

ResultSet rs = pst.executeQuery();

if( rs.next() ) 
{

JOptionPane.showMessageDialog(null, "Successfully Logged In", "Success", JOptionPane.INFORMATION_MESSAGE);

//this.setVisible(false);
//new FrmMain().setVisible(true);

//this.setVisible(false);
//new FrmMain(username).setVisible(true);

this.setVisible(false);
new FrmMain2(username).setVisible(true);



}
else
{
  JOptionPane.showMessageDialog(null, "Failed to log in", "Failure", JOptionPane.WARNING_MESSAGE);
}

    } catch (Exception e) {
      throw e;
    } finally {
      close();
    }

  }


            private void close() {
    close(resultSet);
    close(statement);
    close(connect);
  }

  private void close(AutoCloseable c) throws UnsupportedOperationException {
    try {
      if (c != null) {
        c.close();
      }
    } catch (Exception e) {
    // don't throw now as it might leave following closables in undefined state
    }

}



    /**
     * Creates new form login_panel
     */
    public login_panel() {
        initComponents();
    }



    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jTextField1 = new javax.swing.JTextField();
        jPasswordField1 = new javax.swing.JPasswordField();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jLabel3 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jTextField1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jTextField1ActionPerformed(evt);
            }
        });

        jPasswordField1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jPasswordField1ActionPerformed(evt);
            }
        });

        jLabel1.setText("Username");

        jLabel2.setText("Password");

        jButton1.setText("Login");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jButton2.setText("eXIT");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jLabel3.setFont(new java.awt.Font("Old English Text MT", 1, 36)); // NOI18N
        jLabel3.setText("Login B0$$");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(66, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jButton2)
                        .addContainerGap())
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jLabel3)
                        .addGap(53, 53, 53))))
            .addGroup(layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel1)
                    .addComponent(jLabel2))
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 92, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jButton1))
                    .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, 92, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel3)
                .addGap(38, 38, 38)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jButton1))
                .addGap(4, 4, 4)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 63, Short.MAX_VALUE)
                .addComponent(jButton2))
        );

        pack();
    }// </editor-fold>                        

    private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
    }                                           

    private void jPasswordField1ActionPerformed(java.awt.event.ActionEvent evt) {                                                
        // TODO add your handling code here:
    }                                               

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         


  try{ 


//   login_panel dao = new login_panel();
//   
//   
//   dao.readDataBase();

      this.readDataBase();

     }
  catch(Exception e)
  {
      System.out.println(e.getMessage());
  }


    }                                        

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         


   int dialogButton = JOptionPane.YES_NO_OPTION;

    int dialogResult = JOptionPane.showConfirmDialog(null, "Exit? ", "Information",dialogButton);

        if(dialogResult == JOptionPane.YES_OPTION)
        {
            JOptionPane.showMessageDialog(null, "Thanks for the stay","Confirm",JOptionPane.INFORMATION_MESSAGE);
            System.exit(0);

        }else
        {
            JOptionPane.showMessageDialog(null, "Remaining...","Remaining....",JOptionPane.INFORMATION_MESSAGE);

        }

    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(login_panel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(login_panel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(login_panel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(login_panel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                //new login_panel().setVisible(true);

                login_panel frame = new login_panel();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JPasswordField jPasswordField1;
    private javax.swing.JTextField jTextField1;
    // End of variables declaration                   
}

The code from the second form is

package mysqltryouts;

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

//am cancer

public class FrmMain2 {

    private String userName;

   public FrmMain2(String username) {
   this.userName=username;
    gui();
}


    public void gui()
    {


        JFrame  f = new JFrame("Ma JFrame");

        JPanel p = new JPanel();


        p.setBackground(Color.YELLOW);


        f.setSize(600,400);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


        JButton b1 = new JButton("Back");
        JLabel l1 = new JLabel("Username");
        l1.setText(userName);
        p.add(b1);
        p.add(l1);

        f.add(p);




         f.setVisible(true);
    }


    public static void main(String[] args)
    {
       //new FrmMain2(username);
    }

}

So I want to transfer the username String to my label from MainFrame2. I had a similar problem that I posted it here ( and solved) but I can't do it.....

ExtremeSwat
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1 Answers1

1

You state:

I know it's not good practice to have 2 JFrames

Then don't do this. The login "JFrame" should be a modal JDialog. Period. End of Story.

Why?

Then the main GUI can call the dialog knowing that code control will return right back to the spot where the dialog was made visible once the dialog is no longer visible. Then it will be trivial for the main GUI to query the state of your dialog's user provided data and move forward.

For example: https://stackoverflow.com/a/21462653/522444

Just bite the bullet and do it and you won't regret it.

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