Problem disabling JButton in ActionListener after setText of JLabel

Question

What i want is when i click View to see the label say "Viewing ..." and in the same time the btnView (View Button) to be disabled.
I want the same with the other 2 buttons.
My problem is in ActionListener of the button. It only half works.
I cannot disable (setEnabled(false)) the button after it is pressed and showing the JLabel.
The code i cannot run is the 3 buttons setEnabled (2 in comments).
Any light?
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class BTester extends JFrame implements ActionListener { 
     JButton btnView, btnBook, btnSearch;
     BTester(){     //Constructor
          JPanel p = new JPanel();
     JButton btnView = new JButton( "View" );
     btnView.setActionCommand( "View" );
     btnView.addActionListener(this);
     JButton btnBook = new JButton( "Book" );
     btnBook.setActionCommand( "Book" );
     btnBook.addActionListener(this);
     JButton btnSearch = new JButton( "Search" );
     btnSearch.setActionCommand( "Search" );
     btnSearch.addActionListener(this);
     p.add(btnView);
     p.add(btnBook);
     p.add(btnSearch);
     getContentPane().add(show, "North"); //put text up
getContentPane().add(p, "South"); //put panel of buttons down
setSize(400,200);
setVisible(true);
setTitle("INITIAL BUTTON TESTER");
show.setFont(new Font("Tahoma",Font.BOLD,20));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     
     //actionPerformed implemented (overrided)
     public void actionPerformed( ActionEvent ae) {
String actionName = ae.getActionCommand().trim();
if( actionName.equals( "View" ) ) {
show.setText("Viewing ...");
     btnView.setEnabled(false); // The line of problem
//btnBook.setEnabled(true);
//btnSearch.setEnabled(true);
else if( actionName.equals( "Book" ) ) {
show.setText("Booking ...");
//btnView.setEnabled(true);
//btnBook.setEnabled(false);
//btnSearch.setEnabled(true);
else if( actionName.equals( "Search" ) ) {
show.setText("Searching ...");
//btnView.setEnabled(true);
//btnBook.setEnabled(true);
//btnSearch.setEnabled(false);
} //end actionPerformed
     private JLabel show = new JLabel( "Press a button ... " );
public static void main(String[] args) { 
     new BTester();
} // End BTester class

Answer 1

1. Use code formatting when posting code.
2. You have a Null Pointer Exception since in your constructor you create the JButtons and assign them to a local variable instead of the class member.
Change this
JButton btnView = new JButton( "View" );to:
btnView = new JButton( "View" );