ListSelectionListener怎么在Java中使用
ListSelectionListener怎么在Java中使用？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
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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的监听器；
(2)使用JList或selectionModel的addListSelectionListener添加监听器；
(3)在监听器的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
/*
* Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
*
* redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle or the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
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(" ");
} 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());
}
}
} 看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注创新互联行业资讯频道，感谢您对创新互联的支持。
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