Re: Sharing ListSelection

From:
"Lew" <lew@THRWHITE.remove-dii-this>
Newsgroups:
comp.lang.java.gui
Date:
Wed, 27 Apr 2011 15:50:18 GMT
Message-ID:
<maGdnZgXIpQvs2fVnZ2dnUVZ_hCdnZ2d@comcast.com>
  To: comp.lang.java.gui
John B. Matthews wrote:

perhaps something like this might work:


A couple of things concern me about this code.

<code>
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class SR extends JFrame {


SR extends JFrame, but is nowhere used.

Inheritance? Composition?

  private static boolean useLast = false;


nit: the second initialization to 'false' is redundant, as 'false' is the
default value.

  private static int lastIndex;

  public static void main(String[] args) {
    final JFrame frame = new JFrame();


Not inheritance?

More important: this is not on the EDT.

    frame.setLayout(new BorderLayout());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    final JList list1 = new JList();
    final JList list2 = new JList();

    final DefaultListModel model = new DefaultListModel();
    final DefaultListSelectionModel selectionModel =
      new DefaultListSelectionModel();
    selectionModel.setSelectionMode(
      ListSelectionModel.SINGLE_SELECTION);
    selectionModel.addListSelectionListener(
      new ListSelectionListener() {
      @Override
      public void valueChanged(ListSelectionEvent e) {
        if (useLast) {
          list1.setSelectedIndex(lastIndex);
          list2.setSelectedIndex(lastIndex);
          useLast = false;
        }
      }
    });

    JButton addButton=new JButton("Add Item");
    addButton.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        lastIndex = list1.getSelectedIndex();
        useLast = true;
        model.add(0, "AddedItem 0");
      }

    });

    frame.add(list1, BorderLayout.WEST);
    frame.add(list2, BorderLayout.EAST);
    frame.add(addButton, BorderLayout.SOUTH);

    list1.setModel(model);
    list2.setModel(model);
    list1.setSelectionModel(selectionModel);
    list2.setSelectionModel(selectionModel);

    for (int i = 0; i < 10; i++)
      model.addElement(String.format("Item number %d", i));

    SwingUtilities.invokeLater(new Runnable() {


And here you finally push code onto the EDT, but the construction was not.

      //@Override
      public void run() {
        frame.setSize(500, 500);
        frame.setVisible(true);


No call to 'pack()'.

      }

    });
  }
}
</code>


--
Lew

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