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/OpenJDK 21

Interface ListCellRenderer<E>

Type Parameters:
E - the type of values this renderer can be used for
All Known Implementing Classes:
BasicComboBoxRenderer, BasicComboBoxRenderer.UIResource, DefaultListCellRenderer, DefaultListCellRenderer.UIResource, MetalFileChooserUI.FileRenderer, MetalFileChooserUI.FilterComboBoxRenderer
public interface ListCellRenderer<E>
Identifies components that can be used as "rubber stamps" to paint the cells in a JList. For example, to use a JLabel as a ListCellRenderer, you would write something like this:
 
 class MyCellRenderer extends JLabel implements ListCellRenderer<Object> {
     public MyCellRenderer() {
         setOpaque(true);
     }

     public Component getListCellRendererComponent(JList<?> list,
                                                   Object value,
                                                   int index,
                                                   boolean isSelected,
                                                   boolean cellHasFocus) {

         setText(value.toString());

         Color background;
         Color foreground;

         // check if this cell represents the current DnD drop location
         JList.DropLocation dropLocation = list.getDropLocation();
         if (dropLocation != null
                 && !dropLocation.isInsert()
                 && dropLocation.getIndex() == index) {

             background = Color.BLUE;
             foreground = Color.WHITE;

         // check if this cell is selected
         } else if (isSelected) {
             background = Color.RED;
             foreground = Color.WHITE;

         // unselected, and not the DnD drop location
         } else {
             background = Color.WHITE;
             foreground = Color.BLACK;
         };

         setBackground(background);
         setForeground(foreground);

         return this;
     }
 }
 
 
Since:
1.2
See Also:

Method Summary

Modifier and Type Method Description
Component getListCellRendererComponent(JList<? extends E> list, E value, int index, boolean isSelected, boolean cellHasFocus)
Return a component that has been configured to display the specified value.

Method Details

getListCellRendererComponent

Component getListCellRendererComponent(JList<? extends E> list, E value, int index, boolean isSelected, boolean cellHasFocus)
Return a component that has been configured to display the specified value. That component's paint method is then called to "render" the cell. If it is necessary to compute the dimensions of a list because the list cells do not have a fixed size, this method is called to generate a component on which getPreferredSize can be invoked.
Parameters:
list - The JList we're painting.
value - The value returned by list.getModel().getElementAt(index).
index - The cells index.
isSelected - True if the specified cell was selected.
cellHasFocus - True if the specified cell has the focus.
Returns:
A component whose paint() method will render the specified value.
See Also:

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/swing/ListCellRenderer.html