Name: el35337 Date: 05/13/98


Create a canvas that implements MouseMotionListener.
In the method mouseMoved add an if-statement that checks
to see if any of the buttons are pressed. If so, display
a message.
  Here is a code sample, just add this component to
a frame and drag the mouse inside it.

import java.awt.*;
import java.awt.event.*;

public class DragTest extends Canvas implements MouseListener, MouseMotionListener {

  Point now_at, was_at;

  public DragTest () {
    now_at = new Point(100,100);
    was_at = null;
    setBackground(Color.lightGray);
    addMouseListener(this);
    addMouseMotionListener(this);
  }

  private void drawHandle(Graphics g, Point where_at) {
    g.setXORMode(getBackground());
    g.drawLine(where_at.x, where_at.y-5, where_at.x, where_at.y+5);
    g.drawLine(where_at.x-5, where_at.y, where_at.x+5, where_at.y);
    g.drawOval(where_at.x-3, where_at.y-3, 6, 6);
  }
    

  public Dimension getMinimumSize() {
    return getPreferredSize();
  }

  public Dimension getPreferredSize() {
    return new Dimension (300,300);
  }

  public void mouseClicked(MouseEvent ev) {}
  public void mouseDragged(MouseEvent ev) {
    now_at.x = ev.getX();
    now_at.y = ev.getY();
    repaint();
  }
  public void mouseEntered(MouseEvent ev) {}
  public void mouseExited(MouseEvent ev) {}
  public void mouseMoved(MouseEvent ev) {
    if ( ((ev.getModifiers() & MouseEvent.BUTTON1_MASK) > 0) ||
((ev.getModifiers() & MouseEvent.BUTTON1_MASK) > 0) ||
((ev.getModifiers() & MouseEvent.BUTTON1_MASK) > 0) )
      System.out.println("Mouse 'moved' with a button pressed! Ain't that a 'drag'?");
  }
  public void mousePressed(MouseEvent ev) {}
  public void mouseReleased(MouseEvent ev) {}

  public void paint(Graphics g) {

    if (was_at != null)
      drawHandle(g, was_at);
    else
      was_at = new Point(0,0);

    drawHandle(g, now_at);
    was_at.x = now_at.x;
    was_at.y = now_at.y;
  }

  public void update(Graphics g) {
    paint(g);
  }
}


  I compiled this program with JDK 1.1.6 on Solaris 2.6
Sparc. Here are the results of running this program
on various platforms:
Solaris 2.6 Solaris 2.6 WinNT 4.0
Sparc Sparc Intel
OpenWindows CDE Pentium II
------------------------------------------------------------
Java 1.1.6 Bad Bad (not tested)
 JRE 1.1.6 Bad Bad Good
Java 1.1.2 Good Good Good
(Review ID: 29478)
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