Agfdhyk

i am working on a java application that will serve as a lock screen for my Windows PC. I designed the lock screen to display using swing, when i run the app i works but the task bar is still visible under the app which is not what i want because it can be used to overwrite my app.

I have tried

private Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);

setAlwaysOnTop(true);

setUndecorated(true);

setSize(screenSize.width, screenSize.height);

but it didn't work, so i tried the answer provided for this question, it still did not work.

Any suggestions on how to make the app display in full screen mode and completely hide the task bar?

Below is a Sublime Text screenshot of what i mean.

I am running JDK1.8 on windows 8.0

package appPackage;



import java.awt.*;



public class login extends javax.swing.JFrame {



    private Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

    int width = screenSize.width;

    int height = screenSize.height;

    /**

     * Creates new form login

     */

    public login() {

        initComponents();

        setSize(screenSize.width, screenSize.height);

    }



    /**

     * 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() {



        jPanel1 = new javax.swing.JPanel();

        txtUsername = new javax.swing.JTextField();

        jLabel1 = new javax.swing.JLabel();

        jLabel2 = new javax.swing.JLabel();

        txtPassword = new javax.swing.JTextField();

        btnLogin = new javax.swing.JButton();

        jLabel3 = new javax.swing.JLabel();



        setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);

        setAlwaysOnTop(true);

        setUndecorated(true);

        getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());



        jLabel1.setFont(new java.awt.Font("Serif", 0, 14)); // NOI18N

        jLabel1.setText("Username");



        jLabel2.setFont(new java.awt.Font("Serif", 0, 14)); // NOI18N

        jLabel2.setText("Password");



        btnLogin.setFont(new java.awt.Font("Serif", 0, 15)); // NOI18N

        btnLogin.setText("Login");

        btnLogin.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                btnLoginActionPerformed(evt);

            }

        });



        jLabel3.setFont(new java.awt.Font("Serif", 1, 36)); // NOI18N

        jLabel3.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);

        jLabel3.setText("Login");



        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);

        jPanel1.setLayout(jPanel1Layout);

        jPanel1Layout.setHorizontalGroup(

            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jPanel1Layout.createSequentialGroup()

                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                            .addComponent(jLabel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                            .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 72, javax.swing.GroupLayout.PREFERRED_SIZE))

                        .addGap(18, 18, 18)

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                            .addComponent(txtUsername)

                            .addComponent(txtPassword, javax.swing.GroupLayout.PREFERRED_SIZE, 235, javax.swing.GroupLayout.PREFERRED_SIZE))

                        .addGap(44, 44, 44))

                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()

                        .addComponent(btnLogin, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addGap(127, 127, 127))

                    .addGroup(jPanel1Layout.createSequentialGroup()

                        .addGap(15, 15, 15)

                        .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 279, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addContainerGap())))

        );

        jPanel1Layout.setVerticalGroup(

            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jPanel1Layout.createSequentialGroup()

                .addGap(14, 14, 14)

                .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 79, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                    .addComponent(jLabel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                    .addComponent(txtUsername, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addGap(18, 18, 18)

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                    .addComponent(txtPassword)

                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 39, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addGap(44, 44, 44)

                .addComponent(btnLogin, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addContainerGap(28, Short.MAX_VALUE))

        );



        getContentPane().add(jPanel1, new org.netbeans.lib.awtextra.AbsoluteConstraints(190, 180, 360, 320));



        pack();

        setLocationRelativeTo(null);

    }// </editor-fold>                        



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

        // TODO add your handling code here:

    }                                        



    /**

     * @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.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (InstantiationException ex) {

            java.util.logging.Logger.getLogger(login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (IllegalAccessException ex) {

            java.util.logging.Logger.getLogger(login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (javax.swing.UnsupportedLookAndFeelException ex) {

            java.util.logging.Logger.getLogger(login.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().setVisible(true);

            }

        });

    }



    // Variables declaration - do not modify                     

    private javax.swing.JButton btnLogin;

    private javax.swing.JLabel jLabel1;

    private javax.swing.JLabel jLabel2;

    private javax.swing.JLabel jLabel3;

    private javax.swing.JPanel jPanel1;

    private javax.swing.JTextField txtPassword;

    private javax.swing.JTextField txtUsername;

    // End of variables declaration                   

}

pack();

Why are you using the pack() method?

It will cause the frame to be displayed at its preferred size, which is based on the preferred size of the components added to the frame.

The pack() method will override the size set in the setSize(...) statement since it is executed AFTER the setSize(...) statement.