Section 17.16. The Color Chooser


17.16. The Color Chooser

Swing is chock full of goodies. JColorChooser is yet another ready-made dialog supplied with Swing; it allows your users to choose colors. The following brief example shows how easy it is to use JColorChooser:

     import java.awt.*;     import java.awt.event.*;     import javax.swing.*;     public class LocalColor {       public static void main(String[] args) {         final JFrame frame = new JFrame("LocalColor v1.0");         final Container content = frame.getContentPane(  );  // unnecessary in 5.0+         content.setLayout(new GridBagLayout(  ));         JButton button = new JButton("Change color...");         content.add(button);         button.addActionListener(new ActionListener(  ) {           public void actionPerformed(ActionEvent e) {             Color c = JColorChooser.showDialog(frame,                 "Choose a color", content.getBackground(  ));             if (c != null) content.setBackground(c);           }         });         frame.setSize(200, 200);         frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );         frame.setVisible(true);       }     } 

This example shows a frame window with a single button. When you click on the button, a color chooser pops up. After you select a color, it becomes the background color of the frame window.

Basically, all we have to do is call JColorChooser's static method showDialog( ). In this example, we specified a parent component, a dialog title, and an initial color value. But you can get away with just specifying a parent component. Whatever color the user chooses is returned; if the user presses the Cancel button, null is returned.



    Learning Java
    Learning Java
    ISBN: 0596008732
    EAN: 2147483647
    Year: 2005
    Pages: 262

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