How can I change focus between components

Question

I created A Jframe that consists of Jbutton (Ok),Jbutton(cancel) , Jtextfield and a Jtable . I want when press on OK button , focus changes to Jtextfield, and when press a gain , focus change to JTable .

How can I change focus between Components ?

this what I have tried :

 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
            try{
                Robot robot = new Robot();
          
            robot.keyPress(KeyEvent.VK_TAB);
            robot.keyRelease(KeyEvent.VK_TAB);
            
            KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
               }

            catch (AWTException ex) {
            Logger.getLogger(testSoso.class.getName()).log(Level.SEVERE, null, ex);
        }

        }  

it focus only on JTextfield but does not change focus to JTable

edit: I also tried :

KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent(JTable2);

but did not work

this is the whole code :

package javaapplication5;

import java.awt.AWTException;
import java.awt.KeyboardFocusManager;
import java.awt.Robot;
import java.awt.event.KeyEvent;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Dell
 */
public class javaApp5 extends javax.swing.JFrame {

    /**
     * Creates new form testSoso
     */
    public javaApp5() {
        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() {

        jButton1 = new javax.swing.JButton();
        jTextField1 = new javax.swing.JTextField();
        jScrollPane2 = new javax.swing.JScrollPane();
        jTable2 = new javax.swing.JTable();
        jButton2 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton1.setText("Ok");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jTable2.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null}
            },
            new String [] {
                "Title 1", "Title 2", "Title 3", "Title 4"
            }
        ));
        jScrollPane2.setViewportView(jTable2);

        jButton2.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton2.setText("cancel");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(40, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 374, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(60, 60, 60))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                            .addComponent(jTextField1)
                            .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, 103, Short.MAX_VALUE))
                        .addGap(192, 192, 192))))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(47, 47, 47)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 167, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(65, Short.MAX_VALUE))
        );

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

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        
      //  for(int i=0;i<4;i++){
        //  jTable2.addRowSelectionInterval(0,0);
        try {
            Robot robot = new Robot();
            
            robot.keyPress(KeyEvent.VK_TAB);
            robot.keyRelease(KeyEvent.VK_TAB);
            
            KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
            
        } catch (AWTException ex) {
            Logger.getLogger(javaApp5.class.getName()).log(Level.SEVERE, null, ex);
        }
       // }
    }                                        

    /**
     * @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(javaApp5.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(javaApp5.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(javaApp5.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(javaApp5.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new javaApp5().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTable jTable2;
    private javax.swing.JTextField jTextField1;
    // End of variables declaration                   
}
     

Answer 1

When the user clicks on the OK button, keyboard focus is transferred to the button. Hence simulating pressing the TAB key via class Robot will transfer keyboard focus to the next component which is the cancel button.

Simply calling method requestFocusInWindow worked for me. I added a boolean class member variable, named txtFld , in order to know which component needs to get the focus.

Here is my version of method jButton1ActionPerformed

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    if (txtFld) {
        jTable2.requestFocusInWindow();
    }
    else {
        jTextField1.requestFocusInWindow();
    }
    txtFld = !txtFld;
}

No need for class Robot nor for class KeyboardFocusManager .

For completeness, here is your code with my changes.

package javaapplication5;

public class javaApp5 extends javax.swing.JFrame {

    /**
     * Creates new form testSoso
     */
    public javaApp5() {
        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() {
        jButton1 = new javax.swing.JButton();
        jTextField1 = new javax.swing.JTextField();
        jScrollPane2 = new javax.swing.JScrollPane();
        jTable2 = new javax.swing.JTable();
        jButton2 = new javax.swing.JButton();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jButton1.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton1.setText("Ok");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });
        jTable2.setModel(new javax.swing.table.DefaultTableModel(
                new Object[][]{{null, null, null, null},
                               {null, null, null, null},
                               {null, null, null, null},
                               {null, null, null, null}},
                new String[]{"Title 1", "Title 2", "Title 3", "Title 4"}));
        jScrollPane2.setViewportView(jTable2);
        jButton2.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton2.setText("cancel");
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(layout
                .createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup().addContainerGap(40, Short.MAX_VALUE)
                        .addGroup(layout
                                .createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING,
                                        layout.createSequentialGroup().addComponent(jScrollPane2,
                                                javax.swing.GroupLayout.PREFERRED_SIZE, 374,
                                                javax.swing.GroupLayout.PREFERRED_SIZE)
                                                .addGap(60, 60, 60))
                                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING,
                                        layout.createSequentialGroup().addGroup(layout
                                                .createParallelGroup(
                                                        javax.swing.GroupLayout.Alignment.TRAILING,
                                                        false)
                                                .addComponent(jTextField1)
                                                .addComponent(jButton1,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                                        Short.MAX_VALUE)
                                                .addComponent(jButton2,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE, 103,
                                                        Short.MAX_VALUE))
                                                .addGap(192, 192, 192)))));
        layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(layout.createSequentialGroup().addGap(47, 47, 47)
                                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE,
                                        167, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGap(18, 18, 18)
                                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE,
                                        32, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(
                                        javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 30,
                                        javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(
                                        javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 30,
                                        javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addContainerGap(65, Short.MAX_VALUE)));
        pack();
    }// </editor-fold>

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        if (txtFld) {
            jTable2.requestFocusInWindow();
        }
        else {
            jTextField1.requestFocusInWindow();
        }
        txtFld = !txtFld;
    }

    /**
     * @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 | InstantiationException | IllegalAccessException
                | javax.swing.UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        }
        // </editor-fold>
        // </editor-fold>
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new javaApp5().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    private boolean txtFld;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTable jTable2;
    private javax.swing.JTextField jTextField1;
    // End of variables declaration
}

By the way, if you are learning Swing , I recommend not using the GUI builder of your IDE.