使用Java禁用和启用按钮

Question

How can i disable and enable the button using java (netbeans).Let Suppose i have a button name LiveMonitoring and have some output of ipadrress on jtextarea. what i want is Live Monitoring should be disabled to that extent till i select some ipaddress present on textarea. I am doing it like First i have disabled the button by LiveMonitoring.setEnabled(false) and as soon as i select some text

 package zeeshannisar210;

import java.awt.List;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.io.IOException;
import java.net.Socket;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Scanner;

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JCheckBox;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class Home extends javax.swing.JFrame {
    JCheckBox sh1;
    static Socket csocket;
    public Home() 
    {
        initComponents();
    }





    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel2 = new javax.swing.JPanel();
        Home = new javax.swing.JButton();
        LiveMonitoring = new javax.swing.JButton();
        FileView = new javax.swing.JButton();
        Logs = new javax.swing.JButton();
        Logout = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        Logs1 = new javax.swing.JButton();
        Logs2 = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel2.setBackground(new java.awt.Color(70, 130, 180));

        Home.setBackground(new java.awt.Color(70, 130, 180));
        Home.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        Home.setText("Home");
        Home.setBorderPainted(false);
        Home.setFocusCycleRoot(true);
        Home.setFocusPainted(false);
        Home.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                HomeMouseClicked(evt);
            }
            public void mouseReleased(java.awt.event.MouseEvent evt) {
                HomeMouseReleased(evt);
            }
        });
        Home.addChangeListener(new javax.swing.event.ChangeListener() {
            public void stateChanged(javax.swing.event.ChangeEvent evt) {
                HomeStateChanged(evt);
            }
        });
        Home.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                HomeActionPerformed(evt);
            }
        });

        LiveMonitoring.setBackground(new java.awt.Color(70, 130, 180));
        LiveMonitoring.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        LiveMonitoring.setText("Live Monitoring");
        LiveMonitoring.setBorderPainted(false);
        LiveMonitoring.setFocusCycleRoot(true);
        LiveMonitoring.setFocusPainted(false);
        LiveMonitoring.setFocusable(false);
        LiveMonitoring.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseReleased(java.awt.event.MouseEvent evt) {
                LiveMonitoringMouseReleased(evt);
            }
        });
        LiveMonitoring.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                LiveMonitoringActionPerformed(evt);
            }
        });

        FileView.setBackground(new java.awt.Color(70, 130, 180));
        FileView.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        FileView.setText("File View");
        FileView.setBorderPainted(false);
        FileView.setFocusCycleRoot(true);
        FileView.setFocusPainted(false);

        Logs.setBackground(new java.awt.Color(70, 130, 180));
        Logs.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        Logs.setText("Logs");
        Logs.setBorderPainted(false);
        Logs.setFocusCycleRoot(true);
        Logs.setFocusPainted(false);

        Logout.setBackground(new java.awt.Color(70, 130, 180));
        Logout.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        Logout.setText("Logout");
        Logout.setBorderPainted(false);
        Logout.setFocusCycleRoot(true);
        Logout.setFocusPainted(false);
        Logout.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                LogoutActionPerformed(evt);
            }
        });

        jLabel1.setFont(new java.awt.Font("Lucida Handwriting", 1, 24)); // NOI18N
        jLabel1.setText("        Ease Serve");

        Logs1.setBackground(new java.awt.Color(70, 130, 180));
        Logs1.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        Logs1.setText("Help");
        Logs1.setBorderPainted(false);
        Logs1.setFocusCycleRoot(true);
        Logs1.setFocusPainted(false);

        Logs2.setBackground(new java.awt.Color(70, 130, 180));
        Logs2.setFont(new java.awt.Font("Lucida Handwriting", 1, 14)); // NOI18N
        Logs2.setText("Contact Us");
        Logs2.setBorderPainted(false);
        Logs2.setFocusCycleRoot(true);
        Logs2.setFocusPainted(false);

        jTextArea1.setBackground(new java.awt.Color(173, 216, 230));
        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(21, 21, 21)
                .addComponent(Home, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(146, 146, 146)
                .addComponent(LiveMonitoring, javax.swing.GroupLayout.PREFERRED_SIZE, 185, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(154, 154, 154)
                .addComponent(FileView, javax.swing.GroupLayout.PREFERRED_SIZE, 131, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(179, 179, 179)
                .addComponent(Logs, javax.swing.GroupLayout.PREFERRED_SIZE, 108, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(189, 189, 189)
                .addComponent(Logs1, javax.swing.GroupLayout.PREFERRED_SIZE, 108, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 177, Short.MAX_VALUE)
                .addComponent(Logs2)
                .addGap(84, 84, 84))
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(Logout, javax.swing.GroupLayout.PREFERRED_SIZE, 119, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(39, 39, 39))
            .addComponent(jScrollPane1)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(549, 549, 549)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 271, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(19, 19, 19)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 37, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 103, Short.MAX_VALUE)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 439, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(46, 46, 46)
                        .addComponent(Logout, javax.swing.GroupLayout.PREFERRED_SIZE, 46, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGap(30, 30, 30)
                        .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(Home, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(LiveMonitoring, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(FileView, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(Logs, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(Logs1, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(Logs2, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGap(0, 0, Short.MAX_VALUE))))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(0, 0, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

        pack();
    }// </editor-fold>                        
    private void HomeActionPerformed(java.awt.event.ActionEvent evt) {                                     
    jTextArea1.setText("Clients ID\t\t\tClients Name\t\t\tClients IPAddress\n");
    int i=0;

    Connection conn=MySqlConnect.ConnectDB();
    String Sql="Select * from clients";
    try
    {
        PreparedStatement pst=conn.prepareStatement(Sql);
        ResultSet rs=pst.executeQuery();


        while(rs.next())
        {
            String str=rs.getString("hostname");
            String str1=rs.getString("ipaddress");
            i=i+1;
            jTextArea1.append(i+"\t\t\t"+str+"\t\t\t"+str1+"\n");
        }

    }
    catch(Exception e)
    {
        JOptionPane.showMessageDialog(null,e);
    } 
     LiveMonitoring.setEnabled(false);



    }                                    



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

    new LiveMOnitoring().setVisible(true);
    this.dispose();
    }                                              

    private void LogoutActionPerformed(java.awt.event.ActionEvent evt) {                                       
    new Login().setVisible(true);
    this.dispose();       
    }                                      

    private void LiveMonitoringMouseReleased(java.awt.event.MouseEvent evt) {                                             
    }                                            

    private void HomeMouseReleased(java.awt.event.MouseEvent evt) {                                   
        if (jTextArea1.getSelectedText() != null)
    { 
        LiveMonitoring.setEnabled(true);
        String s = jTextArea1.getSelectedText();

    }
    }                                  

    private void HomeStateChanged(javax.swing.event.ChangeEvent evt) {                                  
        // TODO add your handling code here:
    }                                 

    private void HomeMouseClicked(java.awt.event.MouseEvent evt) {                                  
        if (jTextArea1.getSelectedText() != null)
    { 
        LiveMonitoring.setEnabled(true);
        String s = jTextArea1.getSelectedText();

    }
    }                                 

    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(Home.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Home.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Home.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Home.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 Home().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    public javax.swing.JButton FileView;
    public javax.swing.JButton Home;
    javax.swing.JButton LiveMonitoring;
    public javax.swing.JButton Logout;
    public javax.swing.JButton Logs;
    public javax.swing.JButton Logs1;
    public javax.swing.JButton Logs2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    // End of variables declaration                   
}
);

    } 

but it isn'y enabling the button again although i have selected the ipaddress

Answer 1

Just remove the ActionListener on the button until there is something in the JTextArea. You can also disable buttons but it makes the button look slightly grayed out hence I prefer the method of removing the ActionListener.

JButton.setEnabled(false);