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Wednesday, 1 March 2017

Chapter 30 Exercise 5, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

30.5 (Display a running fan) Rewrite Programming Exercise 15.28 using a thread to control the fan animation.


import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;

import javax.swing.*;

public class Exercise05 extends JApplet{

 private static final long serialVersionUID = 1L;

 public Exercise05() {
  add(new FanControl());
 }
 
 class FanControl extends JPanel {
  private static final long serialVersionUID = 1L;
  private Fan fan; 
  private JScrollBar jScrollBar = new JScrollBar(JScrollBar.HORIZONTAL, 5, 0, 1, 40);

  public FanControl() {
   setLayout(new BorderLayout());
   JPanel panel1 = new JPanel(new GridLayout(1, 3));
   JButton button1 = new JButton("Start");
   JButton button2 = new JButton("Stop");
   JButton button3 = new JButton("Reverse");
   button1.addActionListener(new ActionListener() {    
    @Override
    public void actionPerformed(ActionEvent e) {
     fan.start();
    }
   });
   button2.addActionListener(new ActionListener() {    
    @Override
    public void actionPerformed(ActionEvent e) {
     fan.stop();
    }
   });
   button3.addActionListener(new ActionListener() {    
    @Override
    public void actionPerformed(ActionEvent e) {
     fan.reverse();
    }
   });
   panel1.add(button1);
   panel1.add(button2);
   panel1.add(button3);
   add(panel1, BorderLayout.NORTH);
   
   fan = new Fan(41 - 5);
   add(fan, BorderLayout.CENTER);
   
   jScrollBar.addAdjustmentListener(new AdjustmentListener() {    
    @Override
    public void adjustmentValueChanged(AdjustmentEvent e) {
     fan.setSpeed(41 - jScrollBar.getValue());     
    }
   });
   add(jScrollBar, BorderLayout.SOUTH);
  }
 }
 
 class Fan extends JPanel implements Runnable{
  private static final long serialVersionUID = 1L;
  private Color color;
  private int arc = 0;
  private boolean reverseFan = false;
  private boolean isMoving = true;
  private int spead;
  
  public void setSpeed(int spead) {
   if (spead > 40) {
    spead = 40;
   } else if (spead < 1) {
    spead = 1;
   }
   this.spead = spead;
  }
  
  public void start() {
   isMoving = true;;
  }
  
  public void stop() {
   isMoving = false;
  }
  
  public void reverse() {
   reverseFan = (reverseFan ? false : true);
  }
  
  public Fan(int spead) {
   this.spead = spead;
   color = new Color((int) (Math.random() * 256), (int) (Math.random() * 256), (int) (Math.random() * 256));
   Thread thread = new Thread(this);
   thread.start();
  }
  
  @Override
  protected void paintComponent(Graphics g) {
   super.paintComponent(g);
   int width = getWidth();
   int height = getHeight();
   int diametr = (int) (Math.min(width, height) * 0.8);
   g.setColor(color);
   g.fillArc((width - diametr) / 2, (height - diametr) / 2, diametr, diametr, arc, 30);
   g.fillArc((width - diametr) / 2, (height - diametr) / 2, diametr, diametr, arc + 90, 30);
   g.fillArc((width - diametr) / 2, (height - diametr) / 2, diametr, diametr, arc + 180, 30);
   g.fillArc((width - diametr) / 2, (height - diametr) / 2, diametr, diametr, arc + 270, 30);
   g.drawOval((width - diametr) / 2 - (int) (diametr * 0.05), (height - diametr) / 2 - (int) (diametr * 0.05), (int) (diametr * 1.1), (int) (diametr * 1.1));
   if (reverseFan) {
    arc -= 5;
   } else {
    arc += 5;
   }
  }

  @Override
  public void run() {
   try {
    while (true) {
     Thread.sleep(spead);
     if(isMoving) {
      repaint();
     }
    }
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  }

 }

 public static void main(String[] args) {
  JFrame frame = new JFrame();
  frame.add(new Exercise05());
  frame.setTitle("Exercise05");
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setSize(500, 500);
  frame.setMinimumSize(new Dimension(frame.getWidth(), frame.getHeight()));
  frame.setLocationRelativeTo(null);
  frame.setVisible(true);
 }


}

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