Java-JComboBox中的复选框

Question

我想制作一个JComboBox，它具有用于项目而不是文本的复选框。此外，应该可以检查多个项目并从组件中检索选定的项目。我应该做一个自定义的ComboBoxUI，ComboBoxEditor，ListCellRenderer，ComboPopUp还是其他完全不同的东西？是否有一个现有的Java控件可以做到这一点？

Answer 1

这相当容易实现。在这里找到链接文本

/* * The following code is adapted from Java Forums - JCheckBox in JComboBox URL: http://forum.java.sun.com/thread.jspa?forumID=257&threadID=364705 Date of Access: July 28 2005 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.table.*;
import java.util.*;

public class JComboCheckBox extends JComboBox {
  public JComboCheckBox() { addStuff(); }
  public JComboCheckBox(JCheckBox[] items) { super(items); addStuff(); }
  public JComboCheckBox(Vector items) { super(items); addStuff(); }
  public JComboCheckBox(ComboBoxModel aModel) { super(aModel); addStuff(); }
  private void addStuff() {
    setRenderer(new ComboBoxRenderer());
    addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ae) { itemSelected(); }
    });
  }
  private void itemSelected() {
    if (getSelectedItem() instanceof JCheckBox) {
      JCheckBox jcb = (JCheckBox)getSelectedItem();
      jcb.setSelected(!jcb.isSelected());
    }
  }
  class ComboBoxRenderer implements ListCellRenderer {
    private JLabel defaultLabel;
    public ComboBoxRenderer() { setOpaque(true); }
    public Component getListCellRendererComponent(JList list, Object value, int index,
                boolean isSelected, boolean cellHasFocus) {
      if (value instanceof Component) {
        Component c = (Component)value;
        if (isSelected) {
          c.setBackground(list.getSelectionBackground());
          c.setForeground(list.getSelectionForeground());
        } else {
          c.setBackground(list.getBackground());
          c.setForeground(list.getForeground());
        }
        return c;
      } else {
        if (defaultLabel==null) defaultLabel = new JLabel(value.toString());
        else defaultLabel.setText(value.toString());
        return defaultLabel;
      }
    }
  }
}