java -version:

java version "1.3.1-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-beta-b15)
Java HotSpot(TM) Client VM (build 1.3.1beta-b15, mixed mode)

JTextArea returns the incorrect preferred size when line wrapping is used. The following sample program puts a line-wrapped JTextArea in a JDialog. It prints out the preferred size of the JTextArea before and after the dialog's pack() method is called. These 2 dimensions are not the same - its only correct after pack() has been called.


import java.lang.*;
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.*;

public class JTextAreaWrappingTest {

    private String testStr = "This string should be sufficiently long to demonstrate the problem.";
    WrapArea wrapArea;

    public static void main(String argv[]) {

        JTextAreaWrappingTest myTest = new JTextAreaWrappingTest();

    }

    public JTextAreaWrappingTest () {

        JDialog dialog = new JDialog();

        WrapArea wrapArea = new WrapArea(testStr);
        dialog.getContentPane().setLayout(new FlowLayout());
        dialog.getContentPane().add(wrapArea);

        System.out.println("pre-pack() prefSize = " + wrapArea.getPreferredSize());
        dialog.pack();

// UNCOMMENT THIS LINE AND RE-COMPILE TO DEMONSTRATE THE WORK AROUND
//      dialog.pack();
        System.out.println("post-pack() prefSize = " + wrapArea.getPreferredSize());
        dialog.show();

    } // constructor

    public class WrapArea extends JTextArea {

        public WrapArea(String str) {

            super(str);
            wrapArea = this;

            wrapArea.setColumns(30);
            wrapArea.setLineWrap(true);

        } // constructor

    } // WrapArea

} // JTextAreaWrappingTest