showcolors2.java

java 课件与资料 java 课件与资料 java 课件与资料 java 课件与资料

// Fig. 12.6: ShowColors2.java
// Choosing colors with JColorChooser.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ShowColors2 extends JFrame {
   private JButton changeColorButton;
   private Color color = Color.LIGHT_GRAY;
   private Container container;

   // set up GUI
   public ShowColors2()
   {
      super( "Using JColorChooser" );

      container = getContentPane();
      container.setLayout( new FlowLayout() );

      // set up changeColorButton and register its event handler
      changeColorButton = new JButton( "Change Color" );
      changeColorButton.addActionListener(

         new ActionListener() {  // anonymous inner class

            // display JColorChooser when user clicks button
            public void actionPerformed( ActionEvent event )
            {
               color = JColorChooser.showDialog( 
                  ShowColors2.this, "Choose a color", color );

               // set default color, if no color is returned 
               if ( color == null )
                  color = Color.LIGHT_GRAY;

               // change content pane's background color
               container.setBackground( color );
            }

         } // end anonymous inner class

      ); // end call to addActionListener
 
      container.add( changeColorButton );

      setSize( 400, 130 );
      setVisible( true );

   } // end ShowColor2 constructor

   // execute application
   public static void main( String args[] )
   {
      ShowColors2 application = new ShowColors2();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   }

} // end class ShowColors2