textfieldtest.java

经典的<<C how to program>一书第三版的例程。非常适合于C的初学者。

// Fig. 29.7: TextFieldTest.java
// Demonstrating the JTextField class.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TextFieldTest extends JFrame {
   private JTextField text1, text2, text3;
   private JPasswordField password;

   public TextFieldTest()
   {
      super( "Testing JTextField and JPasswordField" );

      Container c = getContentPane();
      c.setLayout( new FlowLayout() );

      // construct textfield with default sizing
      text1 = new JTextField( 10 );
      c.add( text1 );

      // construct textfield with default text
      text2 = new JTextField( "Enter text here" );
      c.add( text2 );

      // construct textfield with default text and
      // 20 visible elements and no event handler
      text3 = new JTextField( "Uneditable text field", 20 );
      text3.setEditable( false );
      c.add( text3 );

      // construct textfield with default text
      password = new JPasswordField( "Hidden text" );
      c.add( password );

      TextFieldHandler handler = new TextFieldHandler();
      text1.addActionListener( handler );
      text2.addActionListener( handler );
      text3.addActionListener( handler );
      password.addActionListener( handler );

      setSize( 325, 100 );
      show();
   }

   public static void main( String args[] )
   { 
      TextFieldTest app = new TextFieldTest();

      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
               System.exit( 0 );
            }
         }
      );
   }

   // inner class for event handling
   private class TextFieldHandler implements ActionListener {
      public void actionPerformed( ActionEvent e )
      {
         String s = "";

         if ( e.getSource() == text1 )
            s = "text1: " + e.getActionCommand();
         else if ( e.getSource() == text2 )
            s = "text2: " + e.getActionCommand();
         else if ( e.getSource() == text3 )
            s = "text3: " + e.getActionCommand();
         else if ( e.getSource() == password ) {
            JPasswordField pwd =
               (JPasswordField) e.getSource();
            s = "password: " +
                new String( pwd.getPassword() );
         }

         JOptionPane.showMessageDialog( null, s );
      }
   }   
}

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 * (C) Copyright 2000 by Deitel & Associates, Inc. and Prentice Hall.     *
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