JComboBox 多选

import java.awt.Color;  
import java.awt.Component;  
import java.awt.Dimension;  
import java.awt.FlowLayout;  
import java.awt.Graphics;  
import java.awt.Rectangle;  
import java.awt.event.MouseAdapter;  
import java.awt.event.MouseEvent;  
import java.awt.event.MouseListener;  
import java.io.Serializable;  
import java.util.ArrayList;  
import java.util.Collection;  
import java.util.Collections;  
import java.util.HashSet;  
import java.util.List;  
import java.util.Set;  
import java.util.Vector;  
  
import javax.swing.BorderFactory;  
import javax.swing.ComboBoxModel;  
import javax.swing.DefaultComboBoxModel;  
import javax.swing.DefaultListSelectionModel;  
import javax.swing.JCheckBox;  
import javax.swing.JComboBox;  
import javax.swing.JComponent;  
import javax.swing.JFrame;  
import javax.swing.JLabel;  
import javax.swing.JList;  
import javax.swing.ListCellRenderer;  
import javax.swing.ListSelectionModel;  
import javax.swing.SwingUtilities;  
import javax.swing.UIManager;  
import javax.swing.border.Border;  
import javax.swing.event.PopupMenuEvent;  
import javax.swing.event.PopupMenuListener;  
import javax.swing.plaf.basic.BasicComboPopup;  
import javax.swing.plaf.basic.ComboPopup;  
  
/** 
 * 多选ComboBox 
 *  
 * @author tang 
 *  
 * @param <E> 
 */  
@SuppressWarnings({ "serial", "rawtypes", "unchecked" })  
public class MultiSelectComboBox<E> extends CustomComboBox<E> {  
  
    public static void main(String[] args) {  
  
        UIManager.put("ScrollBarUI", com.sun.java.swing.plaf.windows.WindowsScrollBarUI.class.getName());// 设置滚动条样式为window风格的滚动条样式  
  
        final JFrame frame = new JFrame();  
        frame.setLayout(new FlowLayout(FlowLayout.CENTER, 20, 20));  
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
        frame.setSize(500, 500);  
        frame.setLocationRelativeTo(null);  
  
        final MultiSelectComboBox<String> comboBox = new MultiSelectComboBox<>(new String[] { "1", "2", "3", "4", "5", "6", "1", "2", "3", "4", "5", "6", "1", "2",  
                "3", "4", "5", "6" });  
        comboBox.setPreferredSize(new Dimension(150, 26));  
  
        comboBox.setForegroundAndToPopup(Color.YELLOW);  
        comboBox.setBorder(BorderFactory.createLineBorder(Color.GREEN));  
        comboBox.setPopupBorder(BorderFactory.createLineBorder(Color.RED));  
        comboBox.setPopupBackground(Color.DARK_GRAY);  
        comboBox.setSelectionBackground(Color.BLUE);  
        comboBox.setSelectionForeground(Color.RED);  
        comboBox.addPopupMenuListener(new PopupMenuListener() {  
              
            @Override  
            public void popupMenuWillBecomeVisible(PopupMenuEvent e) {  
            }  
              
            @Override  
            public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {  
                System.out.println("选择的值："+comboBox.getSelectedItemsString());  
            }  
              
            @Override  
            public void popupMenuCanceled(PopupMenuEvent e) {  
            }  
        });  
  
        frame.add(comboBox);  
  
        frame.setVisible(true);  
    }  
  
    protected Set<Integer> selectedIndexs = new HashSet<>();  
  
    protected String spliceRegex = ",";  
  
    public MultiSelectComboBox(Vector<E> vector) {  
        super(new DefaultComboBoxModel(vector));  
        init();  
    }  
  
    public MultiSelectComboBox() {  
        super();  
        init();  
    }  
  
    public MultiSelectComboBox(ComboBoxModel<E> aModel) {  
        super(aModel);  
        init();  
    }  
  
    public MultiSelectComboBox(E[] items) {  
        super(items);  
        init();  
    }  
  
    private void init() {  
        setUI(new MultiSelectComboBoxUI());  
        setRenderer(new MultiSelectComboBoxRenderer());  
        setSelectionBackground(getBackground());  
        setSelectionForeground(getForeground());  
        synchAllToPopup();  
        setSelectionModeIsMulti(true);  
    }  
  
    @Override  
    public void updateUI() {  
        setUI(new MultiSelectComboBoxUI());  
  
        setSelectionBackground(selectionBackground);  
        setSelectionForeground(selectionForeground);  
        setPopupBackground(popupBackground);  
        setPopupForeground(popupForeground);  
        setPopupBorder(popupBorder);  
  
        ListCellRenderer<?> renderer = getRenderer();  
        if (renderer instanceof Component) {  
            SwingUtilities.updateComponentTreeUI((Component) renderer);  
        }  
    }  
  
    /** 
     * 设置true为多选模式,false为单选模式 
     *  
     * @param isMulti 
     *            是否多选 
     */  
    public void setSelectionModeIsMulti(boolean isMulti) {  
        if (isMulti) {  
            getPopup().getList().setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);  
        } else {  
            getPopup().getList().setSelectionMode(ListSelectionModel.SINGLE_SELECTION);  
        }  
    }  
  
    /** 
     * 返回true为多选模式,false为单选模式 
     *  
     * @return 
     */  
    public boolean getSelectionModeIsMulti() {  
        return getPopup().getList().getSelectionMode() == ListSelectionModel.MULTIPLE_INTERVAL_SELECTION;  
    }  
  
    /** 
     * 添加Popup事件 
     */  
    public void addPopupMenuListener(PopupMenuListener l) {  
        getPopup().addPopupMenuListener(l);  
    }  
  
    @Override  
    public void setSelectedItem(Object anObject) {  
        super.setSelectedItem(anObject);  
        if (anObject == null) {  
            clearSelectedIndexs();  
        } else {  
            boolean found = false;  
            for (int i = 0; i < dataModel.getSize(); i++) {  
                E element = dataModel.getElementAt(i);  
                if (anObject.equals(element)) {  
                    found = true;  
                    addSelectedIndex(i);  
                    break;  
                }  
            }  
            if (!found) {  
                clearSelectedIndexs();  
            }  
        }  
    }  
  
    public boolean addSelectedIndex(Integer index) {  
        return selectedIndexs.add(index);  
    }  
  
    public boolean isSelected(Integer index) {  
        return selectedIndexs.contains(index);  
    }  
  
    public boolean removeSelectedIndex(Integer index) {  
        return selectedIndexs.remove(index);  
    }  
  
    public void clearSelectedIndexs() {  
        selectedIndexs.clear();  
    }  
  
    /** 
     * 获得选择项的索引 
     *  
     * @return 
     */  
    public Set<Integer> getSelectedIndexs() {  
        return selectedIndexs;  
    }  
  
    /** 
     * 获得已经排序后的选择项的索引 
     *  
     * @return 
     */  
    public List<Integer> getSelectedSortedIndexs() {  
        List<Integer> list = new ArrayList<>(getSelectedIndexs());  
        Collections.sort(list);  
        return list;  
    }  
  
    /** 
     * 获取选择的值 
     *  
     * @return 
     */  
    public List<E> getSelectedItems() {  
        List<E> list = new ArrayList<>();  
        for (Integer index : getSelectedSortedIndexs()) {  
            list.add(getModel().getElementAt(index));  
        }  
        return list;  
    }  
  
    /** 
     * 返回选择的值，用','拼接的字符串 
     *  
     * @return 
     */  
    public String getSelectedItemsString() {  
        List<String> list = new ArrayList<>();  
        for (Integer index : getSelectedSortedIndexs()) {  
            E elementAt = getModel().getElementAt(index);  
            list.add(elementAt == null ? "" : elementAt.toString());  
        }  
        return spliceCollectionValue(list, spliceRegex);  
    }  
  
    public String getSpliceRegex() {  
        return spliceRegex;  
    }  
  
    public void setSpliceRegex(String spliceRegex) {  
        this.spliceRegex = spliceRegex;  
    }  
  
    /** 
     * 用指定字符串将一个字符串数组拼接成一个字符串 
     */  
    public static String spliceArrayValue(Object[] strs, String regex) {  
        if (strs == null || strs.length == 0) {  
            return "";  
        }  
  
        StringBuffer buffer = new StringBuffer();  
        for (Object temp : strs) {  
            if (temp == null) {  
                temp = "";  
            }  
            buffer.append(temp);  
            buffer.append(regex);  
        }  
        int lastRegexIndex = buffer.lastIndexOf(regex);  
        if (lastRegexIndex >= 0) {  
            buffer.delete(lastRegexIndex, buffer.length());// 删除最后一个","  
        }  
        return buffer.toString();  
    }  
  
    /** 
     * 用指定字符串将一个字符串集合拼接成一个字符串 
     */  
    public static String spliceCollectionValue(Collection strs, String regex) {  
        if (strs == null || strs.isEmpty()) {  
            return "";  
        }  
        return spliceArrayValue(strs.toArray(new Object[strs.size()]), regex);  
    }  
  
    public static class MultiSelectComboBoxUI extends CustomComboBoxUI {  
  
        protected JLabel currentValueComponent = new JLabel();  
  
        /** 
         * Paints the currently selected item. 
         */  
        @Override  
        public void paintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus) {  
            currentValueComponent.setText(((MultiSelectComboBox) comboBox).getSelectedItemsString());  
            currentValueComponent.setBackground(comboBox.getBackground());// 清除渲染器原来设置的背景色,将渲染器的背景设置成ComboBox的背景色  
            currentValueComponent.setForeground(comboBox.getForeground());// 清除渲染器原来设置的前景色,将渲染器的前景设置成ComboBox的前景色  
            currentValueComponent.setFont(comboBox.getFont());  
            currentValueComponent.setOpaque(comboBox.isOpaque());  
            if (comboBox.getRenderer() instanceof JComponent) {  
                JComponent r = (JComponent) comboBox.getRenderer();  
                currentValueComponent.setBorder(r.getBorder());  
            }  
  
            int x = bounds.x, y = bounds.y, w = bounds.width, h = bounds.height;  
            if (padding != null) {  
                x = bounds.x + padding.left;  
                y = bounds.y + padding.top;  
                w = bounds.width - (padding.left + padding.right);  
                h = bounds.height - (padding.top + padding.bottom);  
            }  
  
            currentValuePane.paintComponent(g, currentValueComponent, comboBox, x, y, w, h, false);  
        }  
  
        @Override  
        protected ListCellRenderer<?> createRenderer() {  
            return new MultiSelectComboBoxRenderer();  
        }  
  
        @Override  
        protected ComboPopup createPopup() {  
            return new MultiSelectComboBoxPopup(comboBox);  
        }  
  
        public class MultiSelectComboBoxPopup extends BasicComboPopup {  
  
            public MultiSelectComboBoxPopup(JComboBox<?> cBox) {  
                super(cBox);  
            }  
  
            @Override  
            protected JList createList() {  
                return new CustomList<>(comboBox.getModel());  
            }  
  
            @Override  
            protected MouseListener createListMouseListener() {  
                return new MouseAdapter() {  
                    public void mousePressed(MouseEvent anEvent) {  
                        int index = list.getSelectedIndex();  
                        MultiSelectComboBox<?> multiComboBox = (MultiSelectComboBox<?>) comboBox;  
                        if (list.getSelectionMode() == ListSelectionModel.MULTIPLE_INTERVAL_SELECTION) {  
                            if (multiComboBox.isSelected(index)) {  
                                multiComboBox.removeSelectedIndex(index);  
                            } else {  
                                multiComboBox.addSelectedIndex(index);  
                            }  
                        } else {  
                            if (!multiComboBox.isSelected(index)) {  
                                multiComboBox.clearSelectedIndexs();  
                                multiComboBox.addSelectedIndex(index);  
                            }  
                        }  
                        updateListBoxSelectionForEvent(anEvent, false);  
                        comboBox.repaint();  
                        list.repaint();  
                    }  
  
                    public void mouseReleased(MouseEvent anEvent) {  
                        if (!(list.getSelectionMode() == ListSelectionModel.MULTIPLE_INTERVAL_SELECTION)) {  
                            comboBox.setPopupVisible(false);  
                        }  
                    }  
                };  
            }  
  
            @Override  
            protected void configureList() {  
                super.configureList();  
                list.setSelectionModel(new DefaultListSelectionModel() {  
                    public boolean isSelectedIndex(int index) {  
                        return ((MultiSelectComboBox<?>) comboBox).isSelected(index);  
                    }  
                });  
            }  
        }  
    }  
  
    public static class MultiSelectComboBoxRenderer extends JCheckBox implements ListCellRenderer<Object>, Serializable {  
  
        private Border rendererBorder = BorderFactory.createEmptyBorder(0, 1, 0, 0);  
  
        public MultiSelectComboBoxRenderer() {  
            setOpaque(true);  
            setBorder(rendererBorder);  
  
            // 如果觉得默认的CheckBox图标不好看可以直接设置:  
            // setIcon(defaultIcon);  
            // setSelectedIcon(selectedIcon)  
            // setPressedIcon(pressedIcon)  
            // setRolloverEnabled(true);  
            // setRolloverIcon(rolloverIcon)  
            // setRolloverSelectedIcon(rolloverSelectedIcon)  
        }  
  
        @Override  
        public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {  
            setComponentOrientation(list.getComponentOrientation());  
  
            if (isSelected) {  
                setBackground(list.getSelectionBackground());  
                setForeground(list.getSelectionForeground());  
            } else {  
                setBackground(list.getBackground());  
                setForeground(list.getForeground());  
            }  
  
            setEnabled(list.isEnabled());  
            setSelected(isSelected);  
            setText(value == null ? "" : value.toString());  
            setFont(list.getFont());  
  
            return this;  
        }  
  
        public Border getRendererBorder() {  
            return rendererBorder;  
        }  
  
        public void setRendererBorder(Border rendererBorder) {  
            this.rendererBorder = rendererBorder;  
            setBorder(rendererBorder);  
        }  
    }  
}