Java Swing中JList选择事件监听器ListSelectionListener用法示例

Java Swing中JList选择事件监听器ListSelectionListener用法示例

本文实例讲述了java Swing中JList选择事件监听器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iCovZst。

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 andiCovZst 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 OTHEhttp://RWISE) 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 - 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());

}

}

}

运行效果：

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