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package javax.swing;

import java.awt.Component;


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;
    }
 }
 
Author:Hans Muller
Type parameters:
  • <E> – the type of values this renderer can be used for
See Also:
Since:1.2
/** * 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: * <pre> * {@code * 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; * } * } * } * </pre> * * @param <E> the type of values this renderer can be used for * * @see JList * @see DefaultListCellRenderer * * @author Hans Muller * @since 1.2 */
public interface ListCellRenderer<E> {
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.
Params:
  • 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.
See Also:
Returns:A component whose paint() method will render the specified value.
/** * Return a component that has been configured to display the specified * value. That component's <code>paint</code> 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 <code>getPreferredSize</code> * can be invoked. * * @param list The JList we're painting. * @param value The value returned by list.getModel().getElementAt(index). * @param index The cells index. * @param isSelected True if the specified cell was selected. * @param cellHasFocus True if the specified cell has the focus. * @return A component whose paint() method will render the specified value. * * @see JList * @see ListSelectionModel * @see ListModel */
Component getListCellRendererComponent( JList<? extends E> list, E value, int index, boolean isSelected, boolean cellHasFocus); }