Java Swing中JList选择事件 * ListSelectionListener用法示例

本文实例讲述了Java Swing中JList选择事件 * ListSelectionListener用法。分享给大家供大家参考，具体如下：

当JList中的元素被选中时，选择事件将被触发。对于JTable也是一样，你可以把它看做是多个并列的JList。那么，如果程序需要对该事件做出响应，需要以下步骤：

(1)创建一个实现了 ListSelectionListener的 * ；
(2)使用JList或selectionModel的addListSelectionListener添加 * ；
(3)在 * 的valueChanged方法添加响应代码。

在响应代码中需要注意的是getValueIsAdjusting值的判断。测试表明，每当我们进行选择时，valueChanged方法都会被激活多次，其中，在最后的鼠标操作中，getValueIsAdjusting值为false，而在一系列中间操作中，该值均为true。比如说，用鼠标连续划过一串元素时，会有一系列getValueIsAdjusting为true的valueChanged方法激活，且最后一次为false。而我们对选择事件的判定一般是以最后接触为准，因此这里对getValueIsAdjusting值进行一个判断。

常用方法如下：

getLeadSelectionIndex()
返回当前选中的元素的index。

getMinSelectionIndex()
返回选中的多个元素中index的最小值，如果选择为空在返回-1。

getMaxSelectionIndex()
原理同上。

isSelectedIndex(int index)
判断指定index是否被选中。

clearSelection()
清除选中。

getSelectedIndex()
返回被选中的所有元素中最小的index。

getSelectedIndices()
返回一个整型数组，包含被选中的所有index。

getSelectedValue()
返回被选中的，index最小的元素值。

getSelectedValues()
返回一个object数组，包含被选中的所有元素对象。

getSelectedValuesList()
返回一个objectList，包含被选中的所有元素对象。

下面的demo来自于ListSelectionDemo.java

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package awtDemo;
/*
* ListSelectionDemo.java requires no other files.
*/
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
@SuppressWarnings("serial")
public class ListSelectionDemo extends JPanel {
 JTextArea output;
 @SuppressWarnings("rawtypes")
JList list;
 JTable table;
 String newline = "\n";
 ListSelectionModel listSelectionModel;
 @SuppressWarnings({ "unchecked", "rawtypes" })
public ListSelectionDemo() {
   super(new BorderLayout());
   String[] listData = { "one", "two", "three", "four",
              "five", "six", "seven" };
   @SuppressWarnings("unused")
String[] columnNames = { "French", "Spanish", "Italian" };
   list = new JList(listData);
   listSelectionModel = list.getSelectionModel();
   listSelectionModel.addListSelectionListener(
       new SharedListSelectionHandler());
   JScrollPane listPane = new JScrollPane(list);
   JPanel controlPane = new JPanel();
   String[] modes = { "SINGLE_SELECTION",
             "SINGLE_INTERVAL_SELECTION",
             "MULTIPLE_INTERVAL_SELECTION" };
   final JComboBox comboBox = new JComboBox(modes);
   comboBox.setSelectedIndex(2);
   comboBox.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       String newMode = (String)comboBox.getSelectedItem();
       if (newMode.equals("SINGLE_SELECTION")) {
         listSelectionModel.setSelectionMode(
           ListSelectionModel.SINGLE_SELECTION);
       } else if (newMode.equals("SINGLE_INTERVAL_SELECTION")) {
         listSelectionModel.setSelectionMode(
           ListSelectionModel.SINGLE_INTERVAL_SELECTION);
       } else {
         listSelectionModel.setSelectionMode(
           ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
       }
       output.append("----------"
              + "Mode: " + newMode
              + "----------" + newline);
     }
   });
   controlPane.add(new JLabel("Selection mode:"));
   controlPane.add(comboBox);
   //Build output area.
   output = new JTextArea(1, 10);
   output.setEditable(false);
   JScrollPane outputPane = new JScrollPane(output,
            ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
   //Do the layout.
   JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
   add(splitPane, BorderLayout.CENTER);
   JPanel topHalf = new JPanel();
   topHalf.setLayout(new BoxLayout(topHalf, BoxLayout.LINE_AXIS));
   JPanel listContainer = new JPanel(new GridLayout(1,1));
   listContainer.setBorder(BorderFactory.createTitledBorder(
                       "List"));
   listContainer.add(listPane);
 topHalf.setBorder(BorderFactory.createEmptyBorder(5,5,0,5));
   topHalf.add(listContainer);
   //topHalf.add(tableContainer);
   topHalf.setMinimumSize(new Dimension(100, 50));
   topHalf.setPreferredSize(new Dimension(100, 110));
   splitPane.add(topHalf);
   JPanel bottomHalf = new JPanel(new BorderLayout());
   bottomHalf.add(controlPane, BorderLayout.PAGE_START);
   bottomHalf.add(outputPane, BorderLayout.CENTER);
   //XXX: next line needed if bottomHalf is a scroll pane:
   //bottomHalf.setMinimumSize(new Dimension(400, 50));
   bottomHalf.setPreferredSize(new Dimension(450, 135));
   splitPane.add(bottomHalf);
 }
 /**
  * Create the GUI and show it. For thread safety,
  * this method should be invoked from the
  * event-dispatching thread.
  */
 private static void createAndShowGUI() {
   //Create and set up the window.
   JFrame frame = new JFrame("ListSelectionDemo - www.jb51.net");
   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   //Create and set up the content pane.
   ListSelectionDemo demo = new ListSelectionDemo();
   demo.setOpaque(true);
   frame.setContentPane(demo);
   //Display the window.
   frame.pack();
   frame.setVisible(true);
 }
 public static void main(String[] args) {
   //Schedule a job for the event-dispatching thread:
   //creating and showing this application's GUI.
   javax.swing.SwingUtilities.invokeLater(new Runnable() {
     public void run() {
       createAndShowGUI();
     }
   });
 }
 class SharedListSelectionHandler implements ListSelectionListener {
   public void valueChanged(ListSelectionEvent e) {
     ListSelectionModel lsm = (ListSelectionModel)e.getSource();
     //System.out.printf("LeadSelectionIndex is ％s％n",lsm.getLeadSelectionIndex());
     output.append("LeadSelectionIndex is " + lsm.getLeadSelectionIndex() + "\n");
     int firstIndex = e.getFirstIndex();
     int lastIndex = e.getLastIndex();
     boolean isAdjusting = e.getValueIsAdjusting();
     output.append("Event for indexes "
            + firstIndex + " - " + lastIndex
            + "; isAdjusting is " + isAdjusting
            + "; selected indexes:");
     if (lsm.isSelectionEmpty()) {
       output.append(" <none>");
     } else {
       // Find out which indexes are selected.
       int minIndex = lsm.getMinSelectionIndex();
       int maxIndex = lsm.getMaxSelectionIndex();
       for (int i = minIndex; i <= maxIndex; i++) {
         if (lsm.isSelectedIndex(i)) {
           output.append(" " + i);
         }
       }
     }
     output.append(newline);
     output.setCaretPosition(output.getDocument().getLength());
   }
 }
}

运行效果：

希望本文所述对大家java程序设计有所帮助。

来源：http://www.cnblogs.com/pzy4447/p/4912584.html