glasspanedemo.java

java应用开发详解

import javax.swing.*;
import javax.swing.event.MouseInputAdapter;
import java.awt.*;
import java.awt.event.*;

public class GlassPaneDemo 
{
    //声明一个自定义的glass pane类
    static private MyGlassPane myGlassPane;

    public static void main(String[] args) 
    {
    	//声明一个JFrame顶级容器，并添加关闭窗口方法
        JFrame frame = new JFrame("GlassPaneDemo");
        frame.addWindowListener(new WindowAdapter() 
        {
            public void windowClosing(WindowEvent e) 
            {
                System.exit(0);
            }
        });

        //添加一个选择框
        JCheckBox changeButton = 
                new JCheckBox("Glass pane \"visible\"");
        //默认为未选状态
        changeButton.setSelected(false);
        
        //规定其选取触发事件
        changeButton.addItemListener(new ItemListener() 
        {
            public void itemStateChanged(ItemEvent e) 
            {
            	//使glass Pane显示
                myGlassPane.setVisible(e.getStateChange() 
                                       == ItemEvent.SELECTED);
            }
        });

	//得到content pane并布局可视化组件
        Container contentPane = frame.getContentPane();
        //设置布局管理器，添加按钮
        contentPane.setLayout(new FlowLayout());
        contentPane.add(changeButton);
        contentPane.add(new JButton("Button 1"));
        contentPane.add(new JButton("Button 2"));

        //示例化一个菜单栏
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Menu");
        menu.add(new JMenuItem("Do nothing"));
        menuBar.add(menu);
        
        //添加菜单栏到frame
        frame.setJMenuBar(menuBar); 

        //构造自己的glass pane，
        myGlassPane = new MyGlassPane(changeButton, menuBar,
                                      frame.getContentPane());
        //设置glass pane
        frame.setGlassPane(myGlassPane);

        frame.pack();
        frame.setVisible(true);
    }
}


//自己的glass pane类
class MyGlassPane extends JComponent 
{
    //声明一个点类
    Point point;

    //组件的paint方法
    public void paint(Graphics g) 
    {
        if (point != null) 
        {
            g.setColor(Color.red);
            g.fillOval(point.x - 10, point.y - 10, 20, 20);
        }
    }

    public void setPoint(Point p) 
    {
        point = p;
    }

    //构造方法
    public MyGlassPane(AbstractButton aButton, 
                       JMenuBar menuBar,
                       Container contentPane) 
    {
        //实例化一个自己定义的监听器
        CBListener listener = new CBListener(aButton, menuBar,
                                             this, contentPane);
        //添加鼠标监听
        addMouseListener(listener);
        //添加鼠标移动监听
        addMouseMotionListener(listener);
    }
}


//生成自己的适配器类，处理鼠标事件
class CBListener extends MouseInputAdapter 
{
    Toolkit toolkit;
    Component liveButton;
    JMenuBar menuBar;
    MyGlassPane glassPane;
    Container contentPane;
    boolean inDrag = false;

    //构造方法，实例化适配器
    public CBListener(Component liveButton, JMenuBar menuBar,
                      MyGlassPane glassPane, Container contentPane) 
    {
        toolkit = Toolkit.getDefaultToolkit();
        this.liveButton = liveButton;
        this.menuBar = menuBar;
        this.glassPane = glassPane;
        this.contentPane = contentPane;
    }

    //鼠标移动事件
    public void mouseMoved(MouseEvent e) 
    {
        redispatchMouseEvent(e, false);
    }

    //鼠标拖动事件
    public void mouseDragged(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    //鼠标点击事件
    public void mouseClicked(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    //鼠标进入事件
    public void mouseEntered(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    //鼠标移出事件
    public void mouseExited(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    //鼠标按下事件
    public void mousePressed(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    //鼠标释放事件
    public void mouseReleased(MouseEvent e) {
        redispatchMouseEvent(e, true);
        inDrag = false;
    }

    private void redispatchMouseEvent(MouseEvent e,boolean repaint) 
    {
        boolean inButton = false;
        boolean inMenuBar = false;
        Point glassPanePoint = e.getPoint();
        Component component = null;
        Container container = contentPane;
        Point containerPoint = SwingUtilities.convertPoint(
                                        glassPane,
                                        glassPanePoint, 
                                        contentPane);
        int eventID = e.getID();

        if (containerPoint.y < 0) 
        {
            inMenuBar = true;
            container = menuBar;
            containerPoint = SwingUtilities.convertPoint(
                                        glassPane,
                                        glassPanePoint,
                                        menuBar);
            testForDrag(eventID);
        } 

        component = SwingUtilities.getDeepestComponentAt(
                                        container,
                                        containerPoint.x,
                                        containerPoint.y);

        if (component == null) 
        {
            return;
        }

        if (component.equals(liveButton)) 
        {
            inButton = true;
            testForDrag(eventID);
        }

        if (inMenuBar || inButton || inDrag) 
        {
            Point componentPoint = SwingUtilities.convertPoint(
                                        glassPane,
                                        glassPanePoint, 
                                        component);
            component.dispatchEvent(new MouseEvent(component,
                                                 eventID,
                                                 e.getWhen(),
                                                 e.getModifiers(),
                                                 componentPoint.x,
                                                 componentPoint.y,
                                                 e.getClickCount(),
                                                 e.isPopupTrigger()));
        }

        if (repaint) 
        {
            toolkit.beep();
            glassPane.setPoint(glassPanePoint);
            glassPane.repaint();
        }
    }

    private void testForDrag(int eventID) 
    {
        if (eventID == MouseEvent.MOUSE_PRESSED) {
            inDrag = true;
        }
    }
}