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Nuno Silva - 28 Apr 2005 16:21 GMT

Hi, I'm pretty new to Swing, and I'm at the hello world example code from
java.sun.com. I'm trying to add next to the JLabel a JButton, and next to
frame.getContentPane().add(label); I do the same for the JButton created,
but in the GUI only shows the button. Can you explain to me why this happens
and why not appending the button next to the label? And how should I do to
make them put together?

Thanks in advance.

Nuno

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Bjorn Abelli - 28 Apr 2005 21:02 GMT

"Nuno Silva" ...

> Hi, I'm pretty new to Swing, and I'm at the hello
> world example code from java.sun.com.

Your problem would be no different in AWT...

> I'm trying to add next to the JLabel a JButton,
> and next to frame.getContentPane().add(label);
[quoted text clipped - 3 lines]
> and why not appending the button next to
> the label?

The default LayoutManager in a Frame/JFrame is BorderLayout, that has 5
areas, in which only one component can exist at one time.

frame.getContentPane().add(label);

...is "equal" to:

frame.getContentPane().add(label, BorderLayout.CENTER);

So when you "add" the button, it actually *replaces* the label.

> And how should I do to
> make them put together?

There's a lot of possibilities.

You could start with changing the "adding" to actually use different areas,
e.g.

frame.getContentPane().add(label, BorderLayout.CENTER);
frame.getContentPane().add(button, BorderLayout.SOUTH);

...or you could change the LayoutManager to something else than a
BorderLayout before adding the components:

frame.getContentPane().setLayout( new FlowLayout() );

frame.getContentPane().add(label);
frame.getContentPane().add(button);

http://java.sun.com/j2se/1.5.0/docs/api/java/awt/BorderLayout.html
http://java.sun.com/j2se/1.5.0/docs/api/java/awt/FlowLayout.html

BTW, if you're using the latest version (1.5), there's no longer a need for
the "getContentPane()", as you can use "add" directly on the JFrame (which
forwards it to the pane).

// Bjorn A

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