fontslider.java

程序练习中包括书中实例程序代码和练习中要用到的代码,是压缩文件

package examples.windows;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
/** An example class used to demonstrate the use of 
  * the JSlider component
  */
public class FontSlider extends JFrame {
   private JLabel text = new JLabel( "Sample Text",
                                     JLabel.CENTER );
   private static final int MIN_POINTS = 8;
   private static final int MAX_POINTS = 36;
   private JSlider sizer = new JSlider();

   /** Class constructor method
     * @param titleText Window's title bar text
     */
   public FontSlider( String titleText ) {
      super( titleText );
      addWindowListener( new WindowCloser() );
      getContentPane().add( text, BorderLayout.CENTER );

      sizer.setMinimum( MIN_POINTS );
      sizer.setMaximum( MAX_POINTS );
      sizer.setValue( text.getFont().getSize() );
      sizer.setMajorTickSpacing( 4 );
      sizer.setMinorTickSpacing( 1 );
      sizer.setPaintLabels( true );
      sizer.setPaintTicks( true );
      sizer.addChangeListener( new ChangeListener() {
            public void stateChanged( ChangeEvent e ) {
               Font of = text.getFont();
               Font nf = new Font( of.getName(),
                                   of.getStyle(),
                                   sizer.getValue() );
               text.setFont( nf );
               text.repaint();
            }
         }
      );

      JPanel sliderPanel
         = new JPanel( new BorderLayout() );
      sliderPanel.setBorder(
         BorderFactory.createTitledBorder( "Font size" ) );
      sliderPanel.add( sizer, BorderLayout.SOUTH );
      getContentPane().add( sliderPanel,
                            BorderLayout.SOUTH );
      setSize( 250, 175 );
      setVisible( true );
   }

   /** The test method for the class
     * @param args not used
     */
   public static void main( String[] args ) {
      new FontSlider( "Example Slider Usage" );
   }
}