Individual cell heights in JList

Question

hi!
i'm trying to write a cellrenderer for a JList, which can show different cell heights.
i.e. in unselected mode, i only want to show a name of a person; in selected mode, i want do show the name of the person AND some other details in the same cell (like the "add and remove programs"-dialog of Windows XP when you select a program to uninstall (it shows then some information about usage etc.))
if(!isSelected) {
    /* Not selected */
    setPreferredSize(new Dimension(0,25));
    setBackground(Color.BLUE);
} else {
    /* Selected: */
    setPreferredSize(new Dimension(0,45));
    setBackground(Color.RED);                      
}i tried this code in the getListCellRendererComponent(...)-method, but the JList only uses the first size (25) ... i tried to set the JList-propertie fixedCellHeight to -1, but no changes....
does anybody know how i can solve my problem?
thx a lot & greetz
swissManu

Answer 1

thank you for your hints! ... i think i will take some time to develop a Model for my DetailList....
if you like, you can use my improved code.... here it is:
here is the mainpart, the DetailList.java
* Created on 02.12.2004
package detaillist;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Vector;
import javax.swing.JPanel;
* Die Items einer DetailList k�nnen per Klick "aufgeklappt" werden und zeigen
* anschliessend weitere Deteils zum entsprechenden Item.<br>
* Um eigene DetailListItem's mit eigener Darstellung zu erstellen kann einfach
* eine Klasse welche von DetailListItem ableitet erstellt werden.<br>
* <br>
* hoverSelection:<br>
* Mit setHoverSelection(true) wird der Hover-Modus aktiviert. Der Benutzer muss
* anschliessend nur noch �ber Items mit der Maus fahren um diese aufzuklappen.<br>
* <br>
* multiSelection:<br>
* Per setMultiSelection(true) wird dem Benutzer erm�glicht, mehrere Items auf
* einmal aufzuklappen.<br>
* <br>
* ACHTUNG! hoverSelection & multiSelection k�nnen nicht gleichzeitig aktiviert
*          sein!
* @author Manuel Alabor; adapted from Pierre LE LANNIC (weebib)
* @version 1.1
public class DetailList extends JPanel {
    /* Eigenschaften: */
    private boolean hoverSelection = false;
    private boolean multiSelection = false;
    /* Objekte: */
    private Vector selectedItems;
    private ItemSelectionListener itemListener;
    public DetailList() {
          super(new ListLayout());
        setOpaque(true);
          setBackground(Color.WHITE);
          itemListener = new ItemSelectionListener();
          selectedItems = new Vector();
     * Setzt das markierte Item und klappt das betreffende auf bzw. zu.<br>
     * Wird ein aufgeklapptes Item nochmals angeklickt, wird dieses zugeklappt.<br>
     * <br>
     * Ist multiSelection == true, so k�nnen mehrere Items auf einmal aufge-
     * klappt sein. Falls multiSelection == false, so wird das bereits offene
     * Item geschlossen.
     * @param item
     private synchronized void setSelectedItem(DetailListItem item) {
          if (item == null) return;
          /* Offenes Item bei erneutem Klick schliessen: */
          // Offenes Item schliessen und aus der selectedItems-Liste entfernen.
          for (int i = 0; i < selectedItems.size(); i++) {
              DetailListItem selItem = (DetailListItem)selectedItems.get(i);
              if(item == selItem) {
                  if(item.isExpanded()) {
                      item.setExpanded(false);
                      selectedItems.remove(i);
                      System.out.println(selectedItems.size());
                      return;
          /* Ausgeklappte Items zuklappen wenn ein anderes gew�hlt wurde: */
          // Wenn nicht mehrere offene Items erlaubt sind (!multiSelection),
          // werden hier alle anderen Items zugeklappt (falls vorhanden)
          if(selectedItems.size() > 0 && !multiSelection) {
              for (int i = 0; i < selectedItems.size(); i++) {
                  DetailListItem tmpItem = (DetailListItem)selectedItems.get(i);
                  if(item != tmpItem) {
                      tmpItem.setExpanded(false);
                      selectedItems.remove(i);
          /* Geklicktes Item ausklappen: */
          item.setExpanded(true);
          selectedItems.add(item);
          System.out.println(selectedItems.size());
      * F�gt dieser DetailList ein neues DetailListItem hinzu.<br>
      * Es wird dem neuen Item automatisch der ItemSelectionListener dieser
      * DetailList zugewiesen.
      * @param newItem
     public void addItem(DetailListItem newItem) {
         newItem.addMouseListener(itemListener);
         add(newItem);
          revalidate();
          repaint();
     /* Anonyme Klassen: */
      * Diese anonyme Klasse fungiert als Klick-Listener f�r die DetailListItem's
      * dieser DetailList.
      * @author Manuel Alabor
     private class ItemSelectionListener extends MouseAdapter {
          public void mouseClicked(MouseEvent e) {
               Object o = e.getSource();
               if(!hoverSelection) {
                    if (o instanceof DetailListItem) {
                         setSelectedItem((DetailListItem)o);
         * Erm�glicht einen "Hover"-Effekt welche bewirkt dass ein Item auf-
         * geklappt wird sobald sich der Mauszeiger dar�ber befindet.<br>
         * Ist multiSelection aktiv, wird hier nichts unternommen, auch wenn
         * hoverSelection aktiviert ist.
          public void mouseEntered(MouseEvent e) {
               if(hoverSelection && !multiSelection) {
                  Object o = e.getSource();
                    if (o instanceof DetailListItem) {
                        // Wenn ein Item offen ist, soll dieses nicht zugeklappt
                        // werden wenn der Benutzer erneut mit dem Cursor auf das
                        // Item f�hrt.
                        if(selectedItems.size() == 1) {
                            if(selectedItems.get(0) != o) {
                                setSelectedItem((DetailListItem)o);
                         } else {
                             setSelectedItem((DetailListItem)o);
      * Dieser LayoutManager wird benutzt um alle DetailListItems in einer Listen-
      * Anordnung anzuzeigen.
      * @author Manuel Alabor
     private static class ListLayout implements LayoutManager {
          public void removeLayoutComponent(Component comp) {}
          public void addLayoutComponent(String name, Component comp) {}
          public void layoutContainer(Container target) {
               synchronized (target.getTreeLock()) {
                    Insets insets = target.getInsets();
                    int nmembers = target.getComponentCount();
                    int x = insets.left;
                    int y = insets.top;
                    for (int i = 0; i < nmembers; i++) {
                         Component m = target.getComponent(i);
                         if (m.isVisible()) {
                              Dimension d = m.getPreferredSize();
                              m.setBounds(x, y, target.getWidth(), d.height);
                              y += d.height;
          public Dimension preferredLayoutSize(Container target) {
               synchronized (target.getTreeLock()) {
                    Dimension dim = new Dimension(0, 0);
                    int nmembers = target.getComponentCount();
                    for (int i = 0; i < nmembers; i++) {
                         Component m = target.getComponent(i);
                         if (m.isVisible()) {
                              Dimension d = m.getPreferredSize();
                              dim.height += d.height;
                              dim.width = Math.max(dim.width, d.width);
                    Insets insets = target.getInsets();
                    dim.width += insets.left + insets.right;
                    dim.height += insets.top + insets.bottom;
                    return dim;
          public Dimension minimumLayoutSize(Container target) {
               synchronized (target.getTreeLock()) {
                    Dimension dim = new Dimension(0, 0);
                    int nmembers = target.getComponentCount();
                    for (int i = 0; i < nmembers; i++) {
                         Component m = target.getComponent(i);
                         if (m.isVisible()) {
                              Dimension d = m.getMinimumSize();
                              dim.height += d.height;
                              dim.width = Math.max(dim.width, d.width);
                    Insets insets = target.getInsets();
                    dim.width += insets.left + insets.right;
                    dim.height += insets.top + insets.bottom;
                    return dim;
     /* Getter- & Setter-Methoden: */
    public boolean isHoverSelection() {
        return hoverSelection;
    public void setHoverSelection(boolean hoverSelection) {
        multiSelection = false;
        this.hoverSelection = hoverSelection;
    public boolean isMultiSelection() {
        return hoverSelection;
    public void setMultiSelection(boolean multiSelection) {
        hoverSelection = false;
        this.multiSelection = multiSelection;
}this is the DetailListItem.java ... the prototype for individual items:
* Created on 02.12.2004
package detaillist;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Toolkit;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
* Ein Standart-Item f�r DetailList.<br>
* Um eigene Items zu realisieren kann ganz einfach von dieser Klasse abgleitet
* werden und anschliessend das Item individualisiert werden. (Beispiel siehe
* DetailListAdressItem)
* @author Manuel Alabor
* @version 1.0
* @see detaillist.DetailListAdressItem
public abstract class DetailListItem extends JPanel {
    /* Components: */
    protected JLabel lblTitle;
    protected JPanel details;
    private Component margin;
    /* Eigenschaften: */
    protected boolean expanded = false;
    protected int unexpandedHeight = 18;
     * Standart-Konstruktor mit Angabe f�r den Titel sowie ein Symbol.
     * @param text
     * @param icon
    public DetailListItem(String title, String icon) {
        super(new BorderLayout());
        /* Item anpassen: */
        setOpaque(true);
        /* Titel initialisieren: */
        lblTitle = new JLabel(title);
        if(!icon.equals("")) {
            lblTitle.setIcon(new ImageIcon(Toolkit.getDefaultToolkit().createImage(icon)));
        /* details-Panel initialisieren & vorbereiten: */
        details = new JPanel();
        margin = Box.createHorizontalStrut(10);
        /* Components anordnen: */
        add(lblTitle, BorderLayout.NORTH);
        add(margin, BorderLayout.WEST);
        add(details, BorderLayout.CENTER);
        update();
     * Verk�rzter Konstruktor ohne angabe f�r ein Symbol.
     * @param text
    public DetailListItem(String text) {
        this(text, "");
     * Klappt das Item entweder auf oder zu.
     private void update() {
          margin.setVisible(expanded);
          details.setVisible(expanded);
          if (expanded) {
               setBackground(Color.LIGHT_GRAY);
               setBorder(BorderFactory.createLineBorder(Color.BLACK));
          } else {
               setBackground(Color.WHITE);
               setBorder(BorderFactory.createLineBorder(Color.WHITE));
          this.revalidate();
          this.repaint();
      * Im zugeklappten Zustand sollte per unexpandedHeight-Variabel die H�he des
      * Items definiert werden, da es ansonsten jenachdem zu unsch�nen Effekten
      * kommen kann.<br>
      * F�r ein normales Item betr�gt die "Standarth�he" 18pixel.
    public Dimension getPreferredSize() {
        Dimension dim = super.getPreferredSize();
        /* H�he: */
        // Wenn das Item nicht ausgeklappt ist, unexpandedHeight als h�he
        // nehmen:
        if(!expanded) {
            dim.height = unexpandedHeight;
        return dim;
    /* Getter- & Setter-Methoden: */
    public String getTitle() {
        return lblTitle.getText();
    public void setTitle(String text) {
        lblTitle.setText(text);
    public boolean isExpanded() {
        return expanded;
    public void setExpanded(boolean expanded) {
        this.expanded = expanded;
        update();
}here my first basic sample for a item:
* Created on 02.12.2004
package detaillist;
import java.awt.Font;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import com.jgoodies.forms.factories.Borders;
import com.jgoodies.forms.layout.CellConstraints;
import com.jgoodies.forms.layout.FormLayout;
* Ein DetailListItem mit Texteingabe-Feld
* @author Manuel Alabor
* @version 1.0
public class DetailListTextItem extends DetailListItem {
    /* Components: */
    private JTextArea txtText;
     * Standartkonstruktor.
     * @param text
     * @param name
     * @param adress
     * @param email
     * @param photo
    public DetailListTextItem(String title, String icon, String text) {
        super(title, icon);
        unexpandedHeight = 20;  // H�he in zugeklapptem Modus festlegen
        /* lblTitle anpassen: */
        lblTitle.setFont(new Font("Tahoma",Font.BOLD + Font.ITALIC,11));
        lblTitle.setBorder(Borders.createEmptyBorder("1dlu,1dlu,1dlu,1dlu"));
        /* Werte �bernehmen: */
        txtText = new JTextArea(text);
        /* FormLayout f�r details erstellen: */
        details.setLayout(new FormLayout("d:g", "f:30dlu:g"));
        CellConstraints cc = new CellConstraints();
        /* Components hinzuf�gen: */
        details.setBorder(Borders.DLU2_BORDER);
        details.add(new JScrollPane(txtText), cc.xy(1,1));
}and here a testapp:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import detaillist.DetailList;
import detaillist.DetailListItem;
import detaillist.DetailListTextItem;
* Created on 02.12.2004
* @author Manuel Alabor
public class DetailListTest {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        JPanel contentPane = (JPanel)frame.getContentPane();
        contentPane.setLayout(new BorderLayout());
        final DetailList list = new DetailList();
        contentPane.add(new JScrollPane(list), BorderLayout.CENTER);
        JButton btnAdd = new JButton("Add Textitem...");
        btnAdd.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent arg0) {
                 DetailListItem item = new DetailListTextItem("Text-Item", "small_gear.png", "Dies ist ein Testitem");
                 list.addItem(item);
        contentPane.add(btnAdd, BorderLayout.SOUTH);
        JPanel options = new JPanel(new BorderLayout());
        final JCheckBox chkHover = new JCheckBox("HoverSelection");
        final JCheckBox chkMulSel = new JCheckBox("MultiSelection");
        chkHover.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                list.setHoverSelection(chkHover.getModel().isSelected());
                chkMulSel.getModel().setSelected(false);
        options.add(chkHover, BorderLayout.NORTH);
        chkMulSel.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                chkHover.getModel().setSelected(false);
                list.setMultiSelection(chkMulSel.getModel().isSelected());
        options.add(chkMulSel, BorderLayout.SOUTH);
        contentPane.add(options, BorderLayout.NORTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(262,250);
        frame.setLocation(200,200);
        frame.show();
}hope you like it :)