Name: skT45625 Date: 05/01/2000


java version "1.3.0rc3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0rc3-Z)
Java HotSpot(TM) Client VM (build 1.3.0rc3-Z, mixed mode)


After once selecting an element in a JList using the DefaultListSelectionModel
the variable leadIndex in the DefaultListSelectionModel will never return to -
1, which is the initial value. As a result a caret will always be painted
around one of the list elements (the one the leadIndex points at).

The following code will print out a couple of lines that should make the
problem clear. After clearing the selection or removing all elements from a
JList the lead index should be set to -1. But even after removing all elements
from a list the lead index is still >-1, even though there are no elements to
point at.

As far as I can see there is no way to set the leadIndex to -1 after once an
element was selected.

import javax.swing.*;

public class JListTest {
  JList myList = new JList();
  DefaultListModel myModel = new DefaultListModel();
  DefaultListSelectionModel mySelectionModel = new DefaultListSelectionModel();

  public JListTest() {
    myList.setModel(myModel);
    myList.setSelectionModel(mySelectionModel);

    // add elements
    myModel.addElement("Test1, Element1");
    myModel.addElement("Test1, Element2");
    myModel.addElement("Test1, Element3");
    myModel.addElement("Test1, Element4");
    System.out.println();
    System.out.println("List filled with elements");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());


    // select something
    myList.setSelectedIndex(3);
    System.out.println();
    System.out.println("Select index 3");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // unselect
    myList.setSelectedIndex(-1);
    System.out.println();
    System.out.println("Clear selection by setting selection index to -1");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // select something else
    myList.setSelectedIndex(2);
    System.out.println();
    System.out.println("Select index 2");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // unselect in a different way
    myList.clearSelection();
    System.out.println();
    System.out.println("clear selection, 2nd try");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // clear List
    myModel.removeAllElements();
    System.out.println();
    System.out.println("Remove all elements from list");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // add elements
    myModel.addElement("Test2, Element1");
    myModel.addElement("Test2, Element2");
    myModel.addElement("Test2, Element3");
    myModel.addElement("Test2, Element4");
    System.out.println();
    System.out.println("List filled again");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());

    // try to set lead index to -1
    mySelectionModel.setLeadSelectionIndex(-1);
    System.out.println();
    System.out.println("Try to set lead index to -1");
    System.out.println("Selected Index: " + myList.getSelectedIndex());
    System.out.println("Lead Index: " + mySelectionModel.getLeadSelectionIndex
());


  }

  public static void main(String[] args) {
    JListTest jListTest = new JListTest();
    jListTest.invokedStandalone = true;
  }
  private boolean invokedStandalone = false;
}
(Review ID: 104326)
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