JAVA SWING 下拉列表

 import java.awt.Component;import java.awt.FlowLayout;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JList;import javax.swing.UIManager;import javax.swing.plaf.basic.BasicComboBoxRenderer;publicclass ToolTipComboBoxExampleextends JFrame { String[] items= { "jw","ja","la" }; String[] tooltips= { "Javanese ","Japanese ", "Latin" }; public ToolTipComboBoxExample() {super("ToolTip ComboBox Example"); JComboBox combo= new JComboBox(items); combo.setRenderer(new MyComboBoxRenderer()); getContentPane().setLayout(new FlowLayout()); getContentPane().add(combo); }class MyComboBoxRendererextends BasicComboBoxRenderer {public Component getListCellRendererComponent(JList list, Object value,int index, boolean isSelected,boolean cellHasFocus) {if (isSelected) { setBackground(list.getSelectionBackground()); setForeground(list.getSelectionForeground());if (-1< index) { list.setToolTipText(tooltips[index]); } }else { setBackground(list.getBackground()); setForeground(list.getForeground()); } setFont(list.getFont()); setText((value== null)? "" : value.toString());return this; } } publicstatic void main(String args[]) {try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception evt) {} ToolTipComboBoxExample frame= new ToolTipComboBoxExample(); frame.addWindowListener(new WindowAdapter() { publicvoid windowClosing(WindowEvent e) { System.exit(0); } }); frame.setSize(200,140); frame.setVisible(true); }}