javax.swing

Interface ListCellRenderer

All Known Implementing Classes:

BasicComboBoxRenderer, BasicComboBoxRenderer.UIResource, DefaultListCellRenderer, DefaultListCellRenderer.UIResource, MetalFileChooserUI.FileRenderer, MetalFileChooserUI.FilterComboBoxRenderer

public interface ListCellRenderer

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 {
     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;
     }
 }
 

See Also:

JList, DefaultListCellRenderer

Method Summary

Methods

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

Method Detail

getListCellRendererComponent

Component getListCellRendererComponent(JList list,
                                     Object 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:

JList, ListSelectionModel, ListModel