JTree事件

package com.wf;

import javax.swing.*;

import javax.swing.event.TreeSelectionEvent;

import javax.swing.event.TreeSelectionListener;

import javax.swing.tree.DefaultMutableTreeNode;

import javax.swing.tree.TreePath;

import java.awt.*;

class  PaintUserData

{

    public static Color _color = Color.BLACK;

}

class ProjectTree extends JTree implements TreeSelectionListener

{

    private JPanel _panel;

    public ProjectTree(JPanel panel) {

        addTreeSelectionListener(this);

        _panel = panel;

    }

    @Override

    public void valueChanged(TreeSelectionEvent e) {

        TreePath path = e.getNewLeadSelectionPath();

        DefaultMutableTreeNode node = (DefaultMutableTreeNode)path.getLastPathComponent();

        if (node.getUserObject().equals("red"))

        {

            PaintUserData._color = Color.red;

        }

        else if (node.getUserObject().equals("blue"))

        {

            PaintUserData._color = Color.blue;

        }

        else if (node.getUserObject().equals("yellow"))

        {

            PaintUserData._color = Color.yellow;

        }

        else if (node.getUserObject().equals("violet"))

        {

            PaintUserData._color = Color.CYAN;

        }

        else

        {

            PaintUserData._color = Color.black;

        }

        _panel.repaint();

    }

}

class PaintPanel extends JPanel

{

    public PaintPanel() {

    }

    @Override

    public void paint(Graphics g) {

        super.paint(g);

        g.setColor(PaintUserData._color);

        g.drawLine(0, 0, 400, 400);

    }

}

class MainWidget extends JComponent

{

    private GridBagConstraints _gbScrollPane;

    private GridBagConstraints _gbPaintPanel;

    private GridBagLayout _layout;

    private JScrollPane _scrollPane;

    private ProjectTree _projectTree;

    private PaintPanel _paintPanel;

    public MainWidget() {

        _gbScrollPane = new GridBagConstraints();

        _gbPaintPanel = new GridBagConstraints();

        _gbScrollPane.weightx = 0.1;

        _gbScrollPane.weighty = 1;

        _gbScrollPane.gridx = 0;

        _gbScrollPane.gridy = 0;

        _gbScrollPane.fill = GridBagConstraints.BOTH;

        _gbPaintPanel.weightx = 0.9;

        _gbPaintPanel.weighty = 0;

        _gbPaintPanel.gridx = 1;

        _gbPaintPanel.gridy = 0;

        _gbPaintPanel.fill = GridBagConstraints.BOTH;

        _layout = new GridBagLayout();

        setLayout(_layout);

        _scrollPane = new JScrollPane();

        _paintPanel = new PaintPanel();

        _projectTree = new ProjectTree(_paintPanel);

        _scrollPane.getViewport().add(_projectTree);

        add(_scrollPane, _gbScrollPane);

        add(_paintPanel, _gbPaintPanel);

    }

}

public class Test01 extends JFrame

{

    private MainWidget _mainWidget;

    public Test01() {

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        _mainWidget = new MainWidget();

        getContentPane().add(_mainWidget);

    }

    public static void main(String[] args) throws Exception{

        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

        SwingUtilities.invokeLater(new Runnable() {

            @Override

            public void run() {

                Test01 f = new Test01();

                f.setSize(1024, 800);

                f.setLocationRelativeTo(null);

                f.setVisible(true);

            }

        });

    }

}