JComboBox 实现过滤功能?如何实现?

Question

估计这问题都遇到过吧比如一个JComboBox，里面是所有到城市（都是汉字到）。
但要实现到是，比如输入字母，比如B，则显示所有B开头到城市。
而输入汉字，比如南，则显示所有南开头到城市。如果实现？

Answer 1

如果只输入字符的话，
可以用
firstComboBox.setKeySelectionManager(new KeySelectionManager(){ public int selectionForKey(char aKey, ComboBoxModel aModel) {//实现这个接口。输入一个字符，然后返回在model中它的index

return 0;
}

});

Answer 2

也许这个更符合要求：
简单的实现了一下，还有一些问题，lz自行完善吧。
提个思路，看对不。import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;public class ComboBoxTest2 extends JFrame{ /**
 * 
 */
private static final long serialVersionUID = 1L;

private final JComboBox jcb = new JComboBox();

private final DefaultComboBoxModel aModel = new DefaultComboBoxModel();

private final String[] data = { "nanjing", "wuxi", "suzhou", "yangzhou",
"yancheng", "suqian" };

public ComboBoxTest2(){
super("ComboBoxTest");

setSize(300, 200);
setDefaultCloseOperation(EXIT_ON_CLOSE);

for(String tmp : data){
aModel.addElement(tmp);
}
jcb.setModel(aModel);
jcb.setEditable(true);
jcb.getEditor().getEditorComponent().addKeyListener(new KeyAdapter(){ public void keyTyped(KeyEvent e) {
macher(jcb.getEditor().getItem().toString());
}

private void macher(String macher){
if(macher != null){

//这里要实现筛选。根据输入的字符串，在全部城市中筛选合适的程序，添加到model里
                                        //如果什么都没有输入，则将全部城市放在model中。需要做一些判断处理。
String[] machers = {"yangzhou", "yancheng"};

aModel.removeAllElements();
for(String tmp : machers){
aModel.addElement(tmp);
}

}
}
});

JPanel p = new JPanel(new FlowLayout());
p.add(jcb, FlowLayout.LEFT);
add(p, BorderLayout.NORTH);
setVisible(true);
}

public static void main(String args[]){
new ComboBoxTest2();
}
}

Answer 3

这个是我自己 重构的一个FilterComboBox 带有过滤功能的 自己看下吧 代码可行！import java.awt.Component;
import java.awt.event.ActionListener;import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;import javax.swing.AbstractListModel;
import javax.swing.ComboBoxEditor;
import javax.swing.MutableComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.border.*;public class GuiFilterComboBox
    extends JComboBox {    public GuiFilterComboBox() {        setModel(new FilterableComboBoxModel(new ArrayList()));
        setEditor(new MyEditor());
        setEditable(true);
    }    public class FilterableComboBoxModel
        extends AbstractListModel implements MutableComboBoxModel {        private List items;
        private Filter filter;
        private List filteredItems;
        private Object selectedItem;        public FilterableComboBoxModel(List items) {            this.items = new ArrayList(items);
            filteredItems = new ArrayList(items.size());
            updateFilteredItems();
        }
        
        public void addElementList(ArrayList list) { 
         if (list == null || list.size() == 0) {
         return;
         }
         items.addAll(list);
         updateFilteredItems();
        }         public void addElement(Object obj) {            items.add(obj);
            updateFilteredItems();
        }        public void removeElement(Object obj) {            items.remove(obj);
            updateFilteredItems();
        }        public void removeElementAt(int index) {            items.remove(index);
            updateFilteredItems();
        }        public void insertElementAt(Object obj, int index) {}        public void setFilter(Filter filter) {            this.filter = filter;
            updateFilteredItems();
        }        protected void updateFilteredItems() {            fireIntervalRemoved(this, 0, filteredItems.size());
            filteredItems.clear();            if (filter == null) {
                filteredItems.addAll(items);
            }
            else {
                for (Iterator iterator = items.iterator(); iterator.hasNext(); ) {                    Object item = iterator.next();                    if (filter.accept(item)) {
                        filteredItems.add(item);
                    }
                }
            }
            fireIntervalAdded(this, 0, filteredItems.size());
        }        public int getSize() {
            return filteredItems.size();
        }        public Object getElementAt(int index) {
            return filteredItems.get(index);
        }        public Object getSelectedItem() {
            return selectedItem;
        }        public void setSelectedItem(Object val) {            if ( (selectedItem == null) && (val == null)) {
                return;
            }            if ( (selectedItem != null) && selectedItem.equals(val)) {
                return;
            }            if ( (val != null) && val.equals(selectedItem)) {
                return;
            }            selectedItem = val;
            fireContentsChanged(this, -1, -1);
        }
    }    public static interface Filter {
        public boolean accept(Object obj);
    }    class StartsWithFilter
        implements Filter {        private String prefix;
        public StartsWithFilter(String prefix) {
            this.prefix = prefix;
        }        public boolean accept(Object o) {
            return o.toString().toLowerCase().startsWith(prefix.toLowerCase());
        }
    }    public class MyEditor
        implements ComboBoxEditor, DocumentListener {        public JTextField text;
        private volatile boolean filtering = false;
        private volatile boolean setting = false;        public MyEditor() {
            text = new JTextField(35) {
                public void setBorder(Border b) {
                }
            };
            text.getDocument().addDocumentListener(this);
        }        public Component getEditorComponent() {
            return text;
        }        public void setItem(Object item) {
            if (filtering) {
                return;
            }
            setting = true;
            String newText = (item == null) ? "" : item.toString();
            text.setText(newText);
            setting = false;
        }        public Object getItem() {
            return text.getText();
        }        public void selectAll() {
            text.selectAll();
        }        public void addActionListener(ActionListener l) {
            text.addActionListener(l);
        }        public void removeActionListener(ActionListener l) {
            text.removeActionListener(l);
        }        public void insertUpdate(DocumentEvent e) {
            try {
                handleChange();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }        public void removeUpdate(DocumentEvent e) {
            try {
                handleChange();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }        public void changedUpdate(DocumentEvent e) {}        protected void handleChange() {
            if (setting) {
                return;
            }
            filtering = true;            Filter filter = null;
            if (text.getText().length() > 0) {
                filter = new StartsWithFilter(text.getText());
            }            ( (FilterableComboBoxModel) getModel()).setFilter(filter);
            // A bit nasty but it seems to get the popup validated properly
            setPopupVisible(false);
            setPopupVisible(true);
            filtering = false;
        }
    }
}