Anyone got info on JMenuBar Listening?
Does anyone know of a way to listen for mouse input on the JMenuBar?
Ill be honest, im in a bit over my head... But basically I'm overwriting the JMenuBar paintComponent method, so i can put a little [x] button at the top right corner of screen. But now i need to be able to register when someone clicks on it....
It keeps throwin a NullPointerException if i do:My_Menu_Bar.addMouseListener(this);
and if i just doaddMouseListener(this), it will run the program, but it doesnt register the JMenuBar as a point from event.getX().
Any ideas?
[626 byte] By [
SomeDudea] at [2007-11-26 18:47:46]
Also, I can post some code if you want... And just so everyone knows, I have done thorough research, and many attempts on editing my code using the Java API Doc as a reference.... There is zero information on this.
Although I have found out one thing... It seems there are 2 ways to write a Java Application,
1.) where the class extends JFrame
and
2.) where the class extends JPanel
If I wrote the app using #1, then I could do this:My_Menu_Bar.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent evt) {
Menu_Bar_Functions(evt);
}
});
...
public void Menu_Bar_Functions(evt) {
System.out.println("Hey man, you clicked on the menu bar that's a pain in the arse when you write an Application using #2");
}
But, #2 doesnt let you do this. Returns yet again... Null Pointer
I am writing mine using #2 because the code is cleaner and easier to use in my opinion. It's just that the java parser is outputting a extremely vague error message, and im completely stuck.
Any help is greatly appreciated
>It seems there are 2 ways to write a Java Application,
>1.) where the class extends JFrame
>and
>2.) where the class extends JPanel
Sez who? I'm particular about this - I only derive from a GUI class if I need to override a method in that class, and I've never needed to override any methods in JFrame or JPanel, so I've never derived from either.
Anyhowdy, here's a tip about JMenuBar -- it's just another Container. Nothing special. Puts its pants on one leg at a time. Its layout manager seems to behave a bit like BoxLayout, so I wondered if a little dab of glue would do the trick:
import java.awt.*;
import java.net.*;
import javax.swing.*;
public class Example implements Runnable {
public void run() {
JMenuBar mb = new JMenuBar();
JMenu fileMenu = new JMenu("File");
fileMenu.add("New");
fileMenu.add("Open");
mb.add(fileMenu);
mb.add(new JMenu("Edit"));
mb.add(Box.createGlue());
try {
URL url = new URL("http://mud.mm-a7.yimg.com/image/3882365987");
JButton close = new JButton(new ImageIcon(url));
close.setMargin(new Insets(2,2,2,4));
close.setContentAreaFilled(false);
close.setBorderPainted(false);
mb.add(close);
} catch (MalformedURLException e) {
e.printStackTrace();
}
JFrame f = new JFrame("Example");
f.setJMenuBar(mb);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(new JTable(20,10)));
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[]args) {
SwingUtilities.invokeLater(new Example());
}
}
Awesome thanks a ton bro, looks like I should rewrite my application from scratch ;)
Well the major problem here, is that I started coding my application... straight up JCreator. Then fellows of mine recommended JStudio 8, and it generates all of its code. So I was working from that, and it's better that I just write it from scratch with the above method.
Thanks again bro :)
Hey, im still having the same problem when i do this:...
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if (cmd.equals("Exit")) quit();
}
...
protected void quit() {
frame.setVisible(false); // These 2 lines...
frame.dispose(); // Are producing the error.
System.exit(0);
}
It doesn't seem to like it when I call functions from the initial frame(which i made accessable to the entire class).
There must be a specific way in which I have to call these methods im assuming?
Right now all i get is:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
> Right now all i get is:
> Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
is your program structure like this
public class Something
{
JFrame frame;
public Something()
{
JFrame frame = new JFrame();
...
}
actionPerformed()
quit()
}
if it is, you have 2 separate 'JFrame frame' - one is local to the constructor,
the other one is referenced from quit(), and is null
to fix, change
JFrame frame = new JFrame();
to
frame = new JFrame();
Fixed it. :)Message was edited by: SomeDude
> Well the major problem here, is that I started coding my application... straight
> up JCreator. Then fellows of mine recommended JStudio 8, and it generates all of its code.
I'm just a Swing dabbler, but ask the experienced Swing developers here what they think of the code that gets generated when building your GUI with a drag'n'drop tool...
