Name: jk109818 Date: 05/01/2003


FULL PRODUCT VERSION :
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)


FULL OPERATING SYSTEM VERSION :
glibc-2.2.4-31
Linux 2.4.2-2 i686 unknown
Red Hat Linux release 7.1

A DESCRIPTION OF THE PROBLEM :
JFileChooser is often reused over multiple requests for the
user to select a file, but this can result in
inconsistencies between what is displayed in the file
choosers JTextField and the JList (which should display the
currently selected file). This inconsistency can cause
getSelectedFile to return <null> when the user double-clicks
a file in the list. This bug appears have been introduced in
jdk1.4.x, as I cannot reproduce it in jdk1.3.1_02

The problem appears to be with the handling of the
ListSelectionModel for the JList, which become inconsistent
with the JFileChoosers notion of what it's 'selectedFile'
is. This can happen in all file selection modes, and even
if the file chooser has not yet been used.

A particularly bad situation:

  MultipleFileSelection enabled, user selects single file,
later dialog is redisplayed after clearing the selection,
and the JTextField is empty, but the previously selected
file is still highlighted. User double clicks on same file
as before, dialog dissappears, but selected file is reported
as null.


REGRESSION. Last worked in version 1.3.1

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Here are some standalone examples that reproduce the bugs
with the code below

Click the "Select a File..." button
  Select a file and accept by any means (doubleclick, click
ok, press return)
  Notice on stderr your selection was confirmed
  click select button again
    * the JTextField correctly shows your previous selection
as it has
    * not been modified since the selection, but the file is not
    * highlighted in the JList, as the JListModel was wrongfully
    * cleared.
    *** This problem does not appear in jdk1.3.1_02 ***

Select 'Enable multiple files'
  click select button
  select any number of files and accept. stderr confirms
  click select button again
    * both the JTextField and the JList show the previous
selection
    * which is consistent as programmed/used, but
inconsistent with above.

Select 'Enable multiple files' and 'Clear selection...'
  click select button
  select a single file and accept. stderr confirms
  click select button
    * The JTextField is correctly empty, but the previously
selected file
    * is still highlighed in the JList.
  single click the highlighted file
    * The JTextField does not update to display your current
selection
  Press return or click the open button
    * The JFileChooser follows the programmers intent to
have cleared
    * the selected file, even though the user has explicitly
selected
    * one
  double click highlighted file
    * note that JFileChooser dissappears, but stdout shows
that it
    * never saw the selection
    *** This problem does not appear in jdk1.3.1_02 ***

Create a file named "A.txt" in the file choosers default
directory
Enable 'Select multiple files' and 'Pre-Select...'
  click select button
  select a single file _other_ than 'A.txt' and accept.
stderr confirms
  click select button
    * JTextField shows 'A.txt' as selected, but JList highlights
    * previous selection
  single click the highlighted file
    * as above example JTextField does not update
  double click highlighted file
    * as above JFileChooser dissappears, but stdout shows
that 'A.txt'
    * was selected, despite user explicitly double-clicking
a different
    * file. The problem of a programatically selected text
not being
    * highlighted existed in jdk1.3.1_02, though it would at
least
    * de-highlight the previous selection


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import java.io.*;
import javax.swing.*;
import java.awt.event.*;

public class FileChooserBug extends JFrame {
  
  public FileChooserBug() {
    super("File Chooser Bug");
    
    final JFileChooser fc = new JFileChooser();
    // this setting doesn't matter
    fc.setFileSelectionMode (JFileChooser.FILES_ONLY);

    final JCheckBox multiCheck = new JCheckBox("Enable multiple file selection");
    multiCheck.setSelected (fc.isMultiSelectionEnabled());
    multiCheck.addItemListener(new ItemListener() {
        public void itemStateChanged(ItemEvent e) {
          fc.setMultiSelectionEnabled(e.getStateChange()==ItemEvent.SELECTED);
        }
      });
    final JCheckBox clearCheck = new JCheckBox("Clear selection before re-display");
    final JCheckBox preSelectCheck = new JCheckBox("Pre-Select \"A.txt\" before
re-display");
    JButton openButton = new JButton("Select a File...");
    openButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
          
          if (clearCheck.isSelected())
            fc.setSelectedFile(null);
          // Workaround
          // fc.setMultiSelectionEnabled(false);
          // fc.setMultiSelectionEnabled(multiCheck.isSelected());
          if (preSelectCheck.isSelected())
            fc.setSelectedFile (new File("A.txt"));

          int returnVal = fc.showOpenDialog(FileChooserBug.this);
          
          if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fc.getSelectedFile();
            System.err.println("File Selected: "+file);
          } else {
            System.err.println("Selection cancelled by user.");
          }
        }
      });
    Box box = Box.createVerticalBox();
    box.add(multiCheck);
    box.add(clearCheck);
    box.add(preSelectCheck);
    box.add(openButton);
    getContentPane().add(box);
  }

  public static void main(String[] args) {
    JFrame frame = new FileChooserBug();
    
    frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
        }
      });
    
    frame.pack();
    frame.setVisible(true);
  }
}

---------- END SOURCE ----------

CUSTOMER WORKAROUND :
1) To clear previously selected files, call
setFileSelected(null), and if it is to remain or switch to
multi-file-selection-mode then cycle to
single-file-selection, then back to multi-file-selection
before re-displaying the file chooser. That will to deselect
previously selected files in the JList. The JTextField will
be consistent, and while the list is inconsistent if you
wish to pre-select files, it doesn't report false positives,
confusing the user, effectively eliminating the problem of
doubleclicking a preselected file while a different has been
programmatically selected.

2) You can do the same thing as above by changing
directories instead of cycling single-file-selection

3) you can also just use a new JFileChooser each time... but
that get's the same results and takes time/memory at each
instantiation.

Release Regression From : 1.3.1_02
The above release value was the last known release where this
bug was known to work. Since then there has been a regression.

(Review ID: 178837)
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