JListDemo

Tips:

（1）JList不能自动滚动，要想为列表框加上滚动条，必须将JList插入到一个JScrollPane中，然后将JScollPane而不是JList，插入到外围JPanel上

（2）ListSelectionListener
public void valueChanged(ListSelectionEvent event)
在用户选择了若干个选项的同时，将产生一系统列表选择事件。假如用户在一个新选项上单击，当鼠标按下的时候，就会有一个事件报告选项的改变。这是一种过渡型事件。在调用event.isAdjusting()时，如果该选择仍未最终结束则返回true.然后，当松开鼠标时，就产生另一事件，此时isAdjusting返回false.如果对过渡事件不感兴趣，那么可以等待isAdjusting调用返回false的事件。
不过，如果希望只要点击鼠标就给用户一个即时反馈，那么就需要处理所有的事件。

（3）JList不响应鼠标的双击事件。正如Swing设计者所构想的那样，使用列表选择一个选项，然后点击某个按钮执行某个动作。
如果想让JList对双击事件进行响应，必须对JList添加一个鼠标监听器，然后按照下面这样捕获鼠标事件：
eg:

        wordList.addMouseListener(new MouseListener() {

            @Override

            public void mouseReleased(MouseEvent e) {

                // TODO Auto-generated method stub

            }

            @Override

            public void mousePressed(MouseEvent e) {

            }

            @Override

            public void mouseExited(MouseEvent e) {

            }

            @Override

            public void mouseEntered(MouseEvent e) {

            }

            @Override

            public void mouseClicked(MouseEvent e) {

                if (e.getClickCount()==2) {

                    JList source=(JList) e.getSource();

                    Object[] selection=source.getSelectedValues();

                    doAction(selection);

                }

            }

        });

package swing.jlist;

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.ButtonGroup;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JList;

import javax.swing.JPanel;

import javax.swing.JRadioButton;

import javax.swing.JScrollPane;

import javax.swing.event.ListSelectionEvent;

import javax.swing.event.ListSelectionListener;

/*2015-7-8*/

public class JListTest {

    public static void main(String[] args) {

        ListFrame frame = new ListFrame();

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setVisible(true);

        frame.setLocationRelativeTo(null);

    }

}

class ListFrame extends JFrame {

    private static final long serialVersionUID = 1L;

    private static final int DEFAULT_WIDTH = 400;

    private static final int DEFAULT_HEIGHT = 300;

    private JPanel listPanel;

    private JList wordList;

    private JLabel label;

    private JPanel buttonPanel;

    private ButtonGroup group;

    private String prefix = "The ";

    private String suffix = "fox jumps over the lazy dog.";

    public ListFrame() {

        setTitle("ListTest");

        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        String[] words = { "quick", "brown", "hungry", "wild", "silent", "huge", "private", "abstract", "static", "final" };

        wordList = new JList(words);

        wordList.setVisibleRowCount(4);

        JScrollPane scrollPane = new JScrollPane(wordList);

        listPanel = new JPanel();

        listPanel.add(scrollPane);

        wordList.addListSelectionListener(new ListSelectionListener() {

            @Override

            public void valueChanged(ListSelectionEvent e) {

                Object[] values = wordList.getSelectedValues();

                StringBuilder text = new StringBuilder(prefix);

                for (int i = 0; i < values.length; i++) {

                    String word = (String) values[i];

                    text.append(word);

                    text.append("  ");

                }

                text.append(suffix);

                label.setText(text.toString());

            }

        });

        buttonPanel = new JPanel();

        group = new ButtonGroup();

        makeButton("Vertical", JList.VERTICAL);

        makeButton("VERTICAL_WRAP", JList.VERTICAL_WRAP);

        makeButton("HORIZONTAL_WRAP", JList.HORIZONTAL_WRAP);

        add(listPanel, BorderLayout.NORTH);

        label = new JLabel(prefix + suffix);

        add(label, BorderLayout.CENTER);

        add(buttonPanel, BorderLayout.SOUTH);

    }

    private void makeButton(String label, final int orientation) {

        JRadioButton button = new JRadioButton(label);

        buttonPanel.add(button);

        if (group.getButtonCount() == 0) {

            button.setSelected(true);

        }

        group.add(button);

        button.addActionListener(new ActionListener() {

            @Override

            public void actionPerformed(ActionEvent e) {

                wordList.setLayoutOrientation(orientation);

                listPanel.revalidate();

            }

        });

    }

}