import java.awt.Point;
import javax.swing.*;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.swing.JPanel;
public class painttest extends JPanel {
private int pointCount = 0;
private Point[] points = new Point[1000];
public painttest(){ addMouseMotionListener(new MouseMotionAdapter()
{public void MouseDragged(MouseEvent event){
if(pointCount<points.length)
{points[ pointCount ] = event.getPoint(); // find point
++pointCount; // increment number of points in array
repaint();
}}});}
public void paintComponent( Graphics g )
{
super.paintComponent( g ); // clears drawing area
// draw all points in array
for ( int i = 0; i < pointCount; i++ )
g.fillOval( points[i].x,points[i].y , 4, 4 );
} // end method paintComponent
}
Hello.
This is my first class. I pretty much copied from the book word for word. I renamed some classes, such as the class method, but other than that, the names are note for note. Here is the initialization class:
import javax.swing.JFrame;
import java.awt.BorderLayout;
import javax.swing.JLabel;
public class run {
public static void main (String[] args){
JFrame application=new JFrame("Paint");
painttest paint= new painttest();
application.add(paint, BorderLayout.CENTER);
application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
application.setVisible(true);
application.setSize(500,500);
application.add(new JLabel("Profits"));
}}
Again, nothing special. I understand the basics of jframe, buttons, etc. . But I am wondering why this won't paint? That is what the book says. Perhaps the brackets or such? I had some issues with the brackets in this book, but it seems like everything is in place. Any thoughts? Here is the code from the book:
1 // Fig. 14.34: PaintPanel.java
2 // Using class MouseMotionAdapter.
3 import java.awt.Point;
4 import java.awt.Graphics;
5 import java.awt.event.MouseEvent;
6 import java.awt.event.MouseMotionAdapter;
7 import javax.swing.JPanel;
89
public class PaintPanel extends JPanel
10 {
11 private int pointCount = 0; // count number of points
12
13
14
15
16 // set up GUI and register mouse event handler
17 public PaintPanel()
18 {
19 // handle frame mouse motion event
20 addMouseMotionListener(
new MouseMotionAdapter(){
// store drag coordinates and repaint
public void mouseDragged( MouseEvent event )
{
if ( pointCount < points.length )
{
points[ pointCount ] = event.getPoint(); // find point
++pointCount; // increment number of points in array
repaint(); // repaint JFrame
} // end if
}
34 } // end anonymous inner class
35 ); // end call to addMouseMotionListener
36 } // end PaintPanel constructor
37
38 // draw ovals in a 4-by-4 bounding box at specified locations on window
39 public void paintComponent( Graphics g )
40 {
41 super.paintComponent( g ); // clears drawing area
42
43 // draw all points in array
44 for ( int i = 0; i < pointCount; i++ )
45 g.fillOval( points[ i ].x ,points[ i ].y, 4, 4 );
46 } // end method paintComponent
47 } // end class PaintPanel
That and the code snippet below are from Deitel's Java book.
1 // Fig. 14.35: Painter.java
2 // Testing PaintPanel.
3 import java.awt.BorderLayout;
4 import javax.swing.JFrame;
5 import javax.swing.JLabel;
67
public class Painter
8 {
9 public static void main( String[] args )
10 {
11 // create JFrame
12 JFrame application = new JFrame( "A simple paint program" );
13
14
15 application.add( paintPanel, BorderLayout.CENTER ); // in center
16
17 // create a label and place it in SOUTH of BorderLayout
18 application.add( new JLabel( "Drag the mouse to draw" ),
19 BorderLayout.SOUTH );
20
21 application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
application.setSize( 400, 200 ); // set frame size
23 application.setVisible( true ); // display frame
24 } // end main
25 } // end class Painter
