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; public class ToolTipComboBoxExample extends 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 MyComboBoxRenderer extends 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 ; } } public static 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() { public void windowClosing(WindowEvent e) { System.exit( 0 ); } }); frame.setSize( 200 , 140 ); frame.setVisible( true ); }}