Re: problem with jbutton size

From:
Ian Shef <invalid@avoiding.spam>
Newsgroups:
comp.lang.java.help
Date:
Tue, 30 Nov 2010 00:22:50 GMT
Message-ID:
<Xns9E3FB0CE49E86vaj4088ianshef@138.125.254.103>
Robin <r@thevoid1.net> wrote in news:34c9b208-d2a1-493e-b4de-cf2add53e591
@r19g2000prm.googlegroups.com:

import javax.swing.*;
import java.awt.Dimension;
public class but1 {
     public String l (String te) {
          te = te + "TTTTT";
          return te;

     }
     public static void main (String[] args) {
          JFrame d = new JFrame ("TEST");
          JLabel d1 = new JLabel ("test1");
          d.add (d1);
          JButton d2 = new JButton ("test1");
          JButton d3 = new JButton ("test1");
          d.setSize (500, 500);
          d2.setPreferredSize(new Dimension(40, 40));
          d.add (d2);
          d.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

          d.setVisible (true);

     }
}

why does the button take up the whole space of the window that appears
when I run the java program?

Thanks,
-robin


A JFrame contains a JRootPane. The JRootPane contains (among other things)
a content pane. The default content pane has a BorderLayout manager.

When you add a button to the JFrame via

d.add(d2);

you are adding to the center region of the default content pane of the
JRootPane of the JFrame. The behavior that you are seeing is the normal
behavior of a BorderLayout manager.

See the Javadocs for JFrame and for BorderLayout for more information.

While I am at it, I will note the following:

Class names ought to start with a capital letter. This is not enforced by
the compiler, but following this rulle will make it easier to communicate
with other Java programmers, such as the ones in this newsgroup who you are
asking for help. Thus, but1 should be But1, and l should be L.

l is a really bad name for a class. It provides no information, and
(depending upon the font used) can easily be confused with other
characters.

Each region (there are five) maged by a BorderLayout manager can contain
only one component. Because all of your adds are going to the center
region, only the last add is effective. This line is wasted:

d.add (d1);

Several other lines are also wasted because they set things up that are not
used. Given that this is a test program, perhaps you already know this.

Good luck!

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