Re: Frame packing problem with JTextArea containing wrapped text

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.gui
Date:
Sat, 27 Jun 2009 22:24:34 -0700
Message-ID:
<4a46fe91$0$5364$b9f67a60@news.newsdemon.com>
John B. Matthews wrote:

In article <h26c7b$1g0$1@aioe.org>,
 "<<<Klu>>>" <klu@montenegro.usfa.edu> wrote:

Knute Johnson wrote:

<<<Klu>>> wrote:

I want, in other words, to simply be able to specify the text to
display and have everything work, without needing to specify a
magic number somewhere else (such as with setRows) that has to be
kept in synch with that text for things to work.

Layout managers were supposed to save us from this kind of thing.

I want ice cream but I'm not getting it. If you want a JTextArea
to lay out easily, set the rows and columns and quit arguing about
it. And learn how to use GridBagLayout, once you do it will save
you unending grief.

How rude.


Not at all. This was a very mild reproof, and it mentioned ice cream.
Rude would be ridiculing someone's disability: impaired hearing, for
example.


Oh it probably was a little. I write a lot of responses that I delete
and I probably should have deleted this one. Sorry Klu.

I want a JTextArea to lay out easily automatically, without me,
personally, having to count characters and/or experiment to find the
right magic numbers to plug in somewhere. If I wanted to do that I'd
use setLayout(null) and absolute positioning like it was mid-1990s
Visual Basic code I was writing.


You have identified a long-standing anomaly in JTextArea. It is vexing
but not insurmountable.
 

The JTextArea should be able to compute its own number of rows from
the text, wrap policy, and number of columns. This should be obvious,
even to someone in grade school once he's told what a JTextArea is.


You are right, it should and it doesn't. I've been playing around with
this and I can't come up with a good workaround other than calling
pack(), setting the preferred size to the preferred size and calling
pack() again. I did see on the comments to the bug that some folks
found this to not work occasionally. One other possibility is a JLabel
but you will have to come up with at least one dimension for it. I like
how this works,

import java.awt.*;
import javax.swing.*;

public class test extends JFrame {
         String str = "Four score and seven years ago, our " +
   "fathers brought forth on this continent a new nation, conceived " +
   "in liberty and dedicated to the proposition that all men are " +
   "created equal.";

     public test() {
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         setLayout(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();

         JLabel l = new JLabel(
          "<html><div style=\"width: 200px;\">" + str + "</div>");
         l.setBorder(BorderFactory.createLineBorder(Color.RED));
         add(l,c);
         pack();
         setVisible(true);
     }

     public static void main(String[] args) {
         EventQueue.invokeLater(new Runnable() {
             public void run() {
                 new test();
             }
         });
     }
}

As for GridBagLayout, I don't see how it would help here. The problem
is a component misreporting its preferred size. That will screw up
any layout manager that has to deal with that component.


I am a poor student of GridBagLayout, but I took this suggestion to mean
that a flexible layout can be used to compensate for the odd bit of text
that overflows an errant preferred size.


That's what I meant. And that it doesn't expand the size of components
unless you tell it to.

--

Knute Johnson
email s/nospam/knute2009/

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