What is the use of DefaultListCellRenderer class?

[Sarfaraj Khan]

Hi All,

I am new to the programming field. I just started to learn java programming. The class and object concept of java sounds very complex. I am not able to understand the DefaultListCellRenderer class concept. I don't have any idea about the use of DefaultListCellRenderer class. I have searched many java book, but didn't get enough details. I you know anything about the DefaultListCellRenderer class of java, then please share it with me. I am waiting for your reply.

[kelfro]

Hi,

Implementation: This class overrides validate, revalidate, repaint, and firePropertyChange solely to improve performance. If not overridden, these frequently called methods would execute code paths that are unnecessary for the default list cell renderer. If you write your own renderer, take care to weigh the benefits and drawbacks of overriding these methods.

[Zecho]

Before using DefaultListCellRenderer class, you must be aware about following it's methods:

• firePropertyChange(String prName, short oldVal, short newVal)
• firePropertyChange(String prName, Object oldVal, Object newVal)
• firePropertyChange(String prName, long oldVal, long newVal)
• repaint(long tm, int x1, int y1, int width1, int height1)
• firePropertyChange(String prName, int oldVal, int newVal)

[opaper]

Hi friend,

Following example will give you some idea about the use of 'DefaultListCellRenderer class' of java:

import javax.swing.DefaultListCellRenderer;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;

public class CustomBorderDM
 {
  public static void main(String args[]) {
    String labels01[] = { "A", "B", "C", "D","E", "F", "G", "H","I", "J" };
    JFrame gek = new JFrame("Custom Border");
    gek.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container contentPane = gek.getContentPane();
    JList jlist1 = new JList(labels);
    ListCellRenderer renderer = new FocusedTitleListCellRenderer();
    jlist1.setCellRenderer(renderer);
    JScrollPane sp1 = new JScrollPane(jlist1);
    contentPane.add(sp1, BorderLayout.CENTER);
    gek.setSize(400, 200);
    gek.setVisible(true);
  }
}

[MindSpace]

If you want to know about nested classes of DefaultListCellRenderer class, then please refer following list:

1. DefaultListCellRenderer.UIResource
2. Component.FlipBufferStrategy
3. Container.AccessibleAWTContainer
4. Component.AccessibleAWTComponent
5. JLabel.AccessibleJLabel

[Modifier]

Hi,

See if something below code can help you to know about DefaultListCellRenderer class:

class ColorCellRendererDEMO implements DefaultListCellRenderer
 {
  protected DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer();

 
  private final static Dimension preferredSize = new Dimension(0, 10);

  public Component getListCellRendererComponent(JList list1, Object val, int idx,
      boolean isSelected, boolean cellHasFocus) {
    JLabel renderer1 = (JLabel) defaultRenderer.getListCellRendererComponent(list1, val1, idx,
        isSelected, cellHasFocus);
    if (val instanceof Color) {
      renderer1.setBackground((Color) val);
    }
    if(cellHasFocus || isSelected){
      renderer1.setBorder(new LineBorder(Color.DARK_GRAY));
    }else{
      renderer1.setBorder(null);
    }
    
    renderer1.setPreferredSize(preferredSize);
    return renderer1;
  }
}