validationdemo2.java

来自「java 完全探索的随书源码」· Java 代码 · 共 96 行

// ValidationDemo2.java

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

class ValidationDemo2 extends JFrame implements ActionListener
{
   final static int NOTHING = 0;
   final static int SIZE_ONLY = 1;
   final static int SIZE_AND_VALIDATE = 2;

   JLabel l;
   static int option = NOTHING;

   ValidationDemo2 (String title)
   {
      super (title);

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

      JPanel p = new JPanel ();

      JButton b = new JButton ("Change");
      b.addActionListener (this);
      p.add (b);

      l = new JLabel ("Hello");
      p.add (l);

      b = new JButton ("Restore");
      b.addActionListener (this);
      p.add (b);

      getContentPane ().add (p);

      pack ();
      setVisible (true);
   }

   public void actionPerformed (ActionEvent e)
   {
      System.out.println ("Label validity: " + l.isValid ());
      System.out.println ("Label's container validity: " + isValid ());
      System.out.println ("Label's preferred size: " +
                          l.getPreferredSize ());
      System.out.println ("Label's minimum size: " +
                          l.getMinimumSize ());
      System.out.println ("Label's maximum size: " +
                          l.getMaximumSize ());

      if (e.getActionCommand ().equals ("Change"))
          l.setText ("Hello World");
      else
          l.setText ("Hello");

      if (option != NOTHING)
      {
          setSize (getPreferredSize ());

          if (option == SIZE_AND_VALIDATE)
              validate ();
      }

      System.out.println ("Label validity: " + l.isValid ());
      System.out.println ("Label's container validity: " + isValid ());
      System.out.println ("Label's preferred size: " +
                          l.getPreferredSize ());
      System.out.println ("Label's minimum size: " +
                          l.getMinimumSize ());
      System.out.println ("Label's maximum size: " +
                          l.getMaximumSize ());
   }

   public static void main (String [] args)
   {
      if (args.length == 1)
      {
          if (args [0].toUpperCase ().equals ("S"))
              option = SIZE_ONLY;
          else
          if (args [0].toUpperCase ().equals ("V"))
              option = SIZE_AND_VALIDATE;
      }

      new ValidationDemo2 ("Validation Demo2");
   }
}