actionlisteners

[harvey_r01]

Hi All,

I'm a bit of a noob to Java, and was wondering the best way to complete the actions of a menubar. What I have done in my Java code is to create a menu bar, and implement an actionlistener for each menu item, which then has some code in the action listener to perform a task. e.g. Menu item Help -> About creates a new JFrame which is simply an about window.

I have a couple of Q's, is this the right way to do it? it just doesn't look very tidy, and if a menu item needs to do a lot then that will be a big actionlistener, and doesn't make for very readable code. Maybe I should have a menu class, and have a method as each menu items action listener?

Here is my code...
[JAVA]
private void buildMainMenu(JMenuBar menu)
{
JMenu file = new JMenu("&File");
JMenu help = new JMenu( "Help" );

JMenuItem connect = new JMenuItem( "Connect" );
JMenuItem about = new JMenuItem( "&About" );

file.add( connect );
help.add( about );
menu.add( file );
menu.add( help );

// START __ Help - About Information Window
about.addActionListener(
new ActionListener() {

public void actionPerformed( ActionEvent e) {

JFrame aboutFrame = new JFrame( title+" - About" );

Container aboutCont = aboutFrame.getContentPane();

JPanel aboutNorth = new JPanel();
JPanel aboutSouth = new JPanel();
JLabel aboutLabel = new JLabel( title+"\nv1.01", SwingConstants.CENTER);
JButton aboutOK = new JButton( "OK" );
aboutNorth.add( aboutLabel );
aboutSouth.add( aboutOK );
aboutCont.add( aboutNorth, BorderLayout.NORTH );
aboutCont.add( aboutSouth, BorderLayout.SOUTH );
aboutFrame.setSize(150,200);
aboutFrame.show();
aboutOK.addActionListener(

new ActionListener() {
public void actionPerformed( ActionEvent e ) {
aboutFrame.setVisible( false );
aboutFrame.dispose();
}
}
);


}
}
);
// END __ Help - About Information Window
}
[/JAVA]

Currently, the code above simply builds the menu for the JFrame. Help -> about creates a new JFrame, which displays version info about the app, within which is an OK button which I would like to close the current JFrame with. When I try to reference aboutFrame (the JFrame I want to close) in the action listener for the OK button in the JFrame aboutFrame, it doesn't know what i'm talking about, i.e. can't see aboutFrame, but why not??

I will be very grateful to anyone that tries to help a rising Java Dev...

Cheers every1,

- Harvey

[Phaelax]

Here's how I do my menus.

JMenuBar menuBar = new JMenuBar();
menuBar.add(createOptionsMenu());

private JMenu createOptionsMenu()
{
JMenu menu = new JMenu("Options");
menu.add(createOptionsDirectoriesItem());

return menu;
}


private JMenuItem createOptionsDirectoriesItem()
{
JMenuItem item = new JMenuItem("Directories");
class MenuItemListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
//launchPopupPathConfigure();
}
}
ActionListener listener = new MenuItemListener();
item.addActionListener(listener);

return item;
}

[mikeBarr81]

Make the actionlistener as short as possible, it should just call a method. Make that method do all the work. That is how Netbeans would create it for you if you used it's GUI editor.