Re: Button event

From:

Thomas Fritsch <i.dont.like.spam@invalid.com>

Newsgroups:

comp.lang.java.gui

Date:

Thu, 29 Jun 2006 11:35:16 GMT

Message-ID:

<newscache$sidm1j$8v1$1@news.ops.de>

jaap wrote:

I'm a real noob with java. I worked for 4 years with php but now I have
to use java.
I'm looking for a clean way to get an action behind a button/menuitem. I
already found the class actionListener. but the method actionpreformed
is not very clean if you want to give 20 buttons an action. The way I
know is 20 times else if. There must be an better method.

I will try to use my GUI like an interface. It does'nt have to include
much code in my opinion. I think it have to be only some field and
button delcarations.

I personally prefer a design-pattern
roughly alongside the article "How to use Action" at
<http://java.sun.com/docs/books/tutorial/uiswing/misc/action.html>.

My code typically looks like this:

//--begin example-------------------------------------------------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class MainFrame extends JFrame {
   public static void main(String[] args) {
     JFrame frame = new MainFrame();
     frame.pack();
     frame.setVisible(true);
   }

   // Actions used by menu items and buttons:
   private Action openAction = new OpenAction();
   private Action saveAction = new SaveAction();
   // ...more actions

   public MainFrame() {
     jbInit();
   }

   private void jbInit() {
     getContentPane().setLayout(new BorderLayout());

     JMenuBar menuBar = new JMenuBar();
     JMenu fileMenu = new JMenu("File");
     fileMenu.add(openAction);
     fileMenu.add(saveAction);
     menuBar.add(fileMenu);
     // ... more menus and menu-items
     setJMenuBar(menuBar);

     JToolBar toolBar = new JToolBar();
     toolBar.add(openAction);
     toolBar.add(saveAction);
     // ... more tool-bar buttons
     getContentPane().add(toolBar, BorderLayout.NORTH);

     JPanel panel = new JPanel();
     panel.setLayout(new FlowLayout());
     panel.add(new JButton(openAction));
     panel.add(new JButton(saveAction));
     // ... more buttons
     getContentPane().add(panel, BorderLayout.CENTER);
   }

   class OpenAction extends AbstractAction {
     public OpenAction() {
       putValue(Action.NAME, "Open");
       putValue(Action.SMALL_ICON, new ImageIcon("open16.gif"));
       putValue(Action.MNEMONIC_KEY, new Integer('P'));
       putValue(Action.SHORT_DESCRIPTION, "open file");
       putValue(Action.ACCELERATOR_KEY, KeyStroke.getKeyStroke(
                KeyEvent.VK_O, InputEvent.CTRL_MASK));
     }
     public void actionPerformed(ActionEvent e) {
       System.out.println(this);
       // ... do something
     }
   }

   class SaveAction extends AbstractAction {
     public SaveAction() {
       putValue(Action.NAME, "Save");
       putValue(Action.SMALL_ICON, new ImageIcon("save16.gif"));
       putValue(Action.MNEMONIC_KEY, new Integer('A'));
       putValue(Action.SHORT_DESCRIPTION, "save file");
       putValue(Action.ACCELERATOR_KEY, KeyStroke.getKeyStroke(
                KeyEvent.VK_S, InputEvent.CTRL_MASK));
     }
     public void actionPerformed(ActionEvent e) {
       System.out.println(this);
       // ... do something
     }
   }

   // ...more Action classes
}
//--end example------------------------------------------------

--
Thomas