j_text.java

一个十分好的java基础学习的课件

// ////////////////////////////////////////////////////////
// 
// J_Text.java
// 

// ////////////////////////////////////////////////////////

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

public class J_Text extends JFrame
{
    private JTextField [] m_textField = {
        new JTextField("Shown  Text:", 8), new JTextField( "Shown", 15),
        new JTextField("Hidden Text:", 8), new JPasswordField( "Hidden", 15)};

    // set up GUI
    public J_Text( )
    {
        super( "Example of JTextField and JPasswordField" );
    
        Container container = getContentPane( );
        container.setLayout( new FlowLayout( ) );
    
        // construct textfield with default sizing
        m_textField[0].setEditable( false );
        m_textField[2].setEditable( false );
        
        for (int i= 0; i< 4; i++)
            container.add( m_textField[i] );
        
        J_Handler handler = new J_Handler( ); // register event handlers
        m_textField[1].addActionListener( handler );
        m_textField[3].addActionListener( handler );
        
        setSize( 325, 100 );
        setVisible( true );
    } // End of method: J_Text
    
    // private inner class for event handling
    private class J_Handler implements ActionListener
    {
        // process text field events
        public void actionPerformed( ActionEvent event )
        {
            String s="";
            if ( event.getSource( ) == m_textField[1] )
                s = "Shown Text: " + event.getActionCommand( );
            else if (event.getSource( ) == m_textField[3])
                s = "Hidden text: " + new String(((JPasswordField)m_textField[3]).getPassword( ));
            JOptionPane.showMessageDialog( null, s );
        } // End of method: actionPerformed
    } // End of class: J_Handler

    public static void main( String args[] )
    { 
        J_Text application = new J_Text( );
        application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    } // End of method: main
    
}  // End of class J_Text