www.pudn.com > tame.rar > DisabledComboBoxExample.java

/* (swing1.1) */
package tame.examples;

import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.ListCellRenderer;
import javax.swing.UIManager;
import javax.swing.border.EmptyBorder;

import tame.attribute.CanEnable;

/**
@author Nobuo Tamemasa
@version 1.0 12/26/98
*/
public class DisabledComboBoxExample extends JFrame {

  public DisabledComboBoxExample() {
    super("Disabled Item ComboBox Example");

    Object[] items = {
      new ComboItem("A")      ,new ComboItem("B"),
      new ComboItem("1",false),new ComboItem("2",false),
      new ComboItem("abc")    ,new ComboItem("def")
    };

    JComboBox combo = new JComboBox(items);
    combo.setRenderer(new ComboRenderer());
    combo.addActionListener(new ComboListener(combo));

    getContentPane().setLayout(new FlowLayout());
    getContentPane().add(combo);
    setSize(300, 100);
    setVisible(true);
  }

  public static void main (String args[]) {
    DisabledComboBoxExample frame = new DisabledComboBoxExample();
    frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
	System.exit(0);
      }
    });
  }

  class ComboRenderer extends JLabel implements ListCellRenderer {

    public ComboRenderer() {
      setOpaque(true);
      setBorder(new EmptyBorder(1, 1, 1, 1));
    }

    public Component getListCellRendererComponent( JList list,
           Object value, int index, boolean isSelected, boolean cellHasFocus) {
      if (isSelected) {
        setBackground(list.getSelectionBackground());
        setForeground(list.getSelectionForeground());
      } else {
        setBackground(list.getBackground());
        setForeground(list.getForeground());
      }
      if (! ((CanEnable)value).isEnabled()) {
        setBackground(list.getBackground());
        setForeground(UIManager.getColor("Label.disabledForeground"));
      }
      setFont(list.getFont());
      setText((value == null) ? "" : value.toString());
      return this;
    }
  }

  class ComboListener implements ActionListener {
    JComboBox combo;
    Object currentItem;

    ComboListener(JComboBox combo) {
      this.combo  = combo;
      combo.setSelectedIndex(0);
      currentItem = combo.getSelectedItem();
    }

    public void actionPerformed(ActionEvent e) {
      Object tempItem = combo.getSelectedItem();
      if (! ((CanEnable)tempItem).isEnabled()) {
        combo.setSelectedItem(currentItem);
      } else {
        currentItem = tempItem;
      }
    }
  }

  class ComboItem implements CanEnable {
    Object  obj;
    boolean isEnable;

    ComboItem(Object obj,boolean isEnable) {
      this.obj      = obj;
      this.isEnable = isEnable;
    }

    ComboItem(Object obj) {
      this(obj, true);
    }

    public boolean isEnabled() {
      return isEnable;
    }

    public void setEnabled(boolean isEnable) {
      this.isEnable = isEnable;
    }

    public String toString() {
      return obj.toString();
    }
  }
}