mousemotioneventdemo.java

Java样例程序集合：2D

/*
 * MouseMotionEventDemo.java is a 1.2/1.3/1.4 example
 * that requires the following file:
 *   BlankArea.java
 */

import javax.swing.*;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;

import java.awt.event.MouseMotionListener;
import java.awt.event.MouseEvent;

public class MouseMotionEventDemo extends JPanel 
                                  implements MouseMotionListener {
    BlankArea blankArea;
    JTextArea textArea;
    static final String newline = "\n";

    public MouseMotionEventDemo() {
        super(new GridBagLayout());
        GridBagLayout gridbag = (GridBagLayout)getLayout();
        GridBagConstraints c = new GridBagConstraints();

        c.fill = GridBagConstraints.BOTH;
        c.gridwidth = GridBagConstraints.REMAINDER;
        c.weightx = 1.0;
        c.weighty = 1.0;

        c.insets = new Insets(1, 1, 1, 1);
        blankArea = new BlankArea(new Color(0.98f, 0.97f, 0.85f));
        gridbag.setConstraints(blankArea, c);
        add(blankArea);

        c.insets = new Insets(0, 0, 0, 0);
        textArea = new JTextArea();
        textArea.setEditable(false);
        JScrollPane scrollPane = new JScrollPane(textArea,
                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        scrollPane.setPreferredSize(new Dimension(200, 75));
        gridbag.setConstraints(scrollPane, c);
        add(scrollPane);

        //Register for mouse events on blankArea and panel.
        blankArea.addMouseMotionListener(this);
        addMouseMotionListener(this);

        setPreferredSize(new Dimension(450, 450));
        setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
    }

    public void mouseMoved(MouseEvent e) {
       saySomething("Mouse moved", e);
    }

    public void mouseDragged(MouseEvent e) {
       saySomething("Mouse dragged", e);
    }

    void saySomething(String eventDescription, MouseEvent e) {
        textArea.append(eventDescription 
                        + " (" + e.getX() + "," + e.getY() + ")"
                        + " detected on "
                        + e.getComponent().getClass().getName()
                        + newline);
        textArea.setCaretPosition(textArea.getDocument().getLength());
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        JFrame frame = new JFrame("MouseMotionEventDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new MouseMotionEventDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //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();
            }
        });
    }
}