Solved

buttons to increase and decrease variables at runtime

Posted on 2000-03-26
5
252 Views
Last Modified: 2006-11-17
Bellow is my code which shows the movement of the ball. Its bouncing with the parameters of gravity.

I want to add a button that should increase its movement and another button to decrease its movement.

==> to summarize, place two buttons: one should increase the value of gravity and another should decrease the value of gravity



import java.applet.Applet;
import java.applet.*;
import java.lang.*;
import java.awt.*;

//Creating a Main class Moving Ball
public class BouncingBall extends Applet implements Runnable {
 

   //Variable Initialization  
   int Direction_On_X = 0;  
   int Direction_On_Y = 0;
   int x_position     = 0;    
   int y_position     = 0;
   int oldx_position  = 0;  
   int oldy_position  = 0;
   int Squashed      = 0;       
   //For movemnt Calculation
   double gravity         = 9.83;
   double dist            = 0.0;
   double velocity        = 0.0;  
   double BouncingFactor  = 0.4;  
   double Temporaray;
   Double Doublenum;
   String bname;
   //Initializing a thread
   Thread thread_Instance;
 
   
//Method to squashed the ball
public void SquashedTheBall()
{
  Squashed = 1;
  repaint();  
}

//Method to beginthe animation , calling by start method
 public void Begin()
  {
     if (thread_Instance == null)
     {
      //
      thread_Instance = new Thread(this);
      thread_Instance.start();
     }
  }


//It will satrt the animation
  public void start()  
  {
      Begin();      
  }
   
  public void run()  
  {
     Thread.currentThread().setPriority(Thread.NORM_PRIORITY);
     while (true)
     {  
      motion();  
      try {
      Thread.sleep(50);  
     }
    catch (Exception sleepProblem)
     {}
 }
}

//Painting the ball , normaly and Squashed
public void paint(Graphics g)  
 {      

     g.setColor(getBackground());  
     g.fillOval(oldx_position,oldy_position,40,40);
     g.setColor(Color.red);       
     if(Squashed == 1 )
     {
      g.fillOval(x_position, y_position, 33, 25);
      Squashed = 0;
     }
     else
     {
      g.fillOval(x_position, y_position, 40, 40);
     }
 }

 //It will display the ball motion
private void motion()  
   {      
     //Variables updation
     oldx_position = x_position;      
     oldy_position = y_position;      
 
        if (Direction_On_Y == 0)
       {      
        //calculate the distance
        dist = velocity + (1/2)*gravity;    
        //Calculate the velocity      
        velocity = velocity + gravity;      
        //Calculate Y posiiton
         y_position+=(int)dist/10;
        //If ball reached bottom
        if (y_position > 300)
         {
           SquashedTheBall();
           Direction_On_Y = 1;                         
          //Adjust for going below 390...  
         dist = y_position - 300;      
         velocity = Math.sqrt((velocity*velocity) -  2*gravity*dist);
           Temporaray = velocity * (BouncingFactor/50);  //Calculate the new velocity because of collision.    
           velocity = velocity - Temporaray;      
         y_position = 300;
        }
     }
      //If Ball is bouncing up, do calculations and adjust y_position accordingly      
      
      else      
      {
        
      if(velocity <= 0)
       {
            Direction_On_Y = 0;
         }
      else
       {
             dist = velocity + (1/2)*(gravity);
             velocity = velocity - gravity;           
             y_position -= dist/20;
         }       
            
               
      if(y_position <= 0)      
      {
      Direction_On_Y = 0;
      y_position = 0;
      }

  }            
       //If ball is moving on right hand
       if (Direction_On_X == 0)
          {  
            //Move the ball by the factor of 2
            x_position+=2;
         
      if (x_position > 800)
         {
           // If it is opposite
           Direction_On_X = 1;
             x_position = 390;
         }
       }
      else
          {
          x_position-=2;

         if (x_position <= 0)
         {  
            Direction_On_X = 0;
              x_position = 0;
         }
        }
       repaint();  
     }
 
   
 
 }







0
Comment
Question by:redgreenred
  • 2
  • 2
5 Comments
 
LVL 16

Expert Comment

by:heyhey_
ID: 2660074
so - add two buttons, add ActionListeners and increase / decrease the 'gravity' variable value on button press.
0
 

Author Comment

by:redgreenred
ID: 2661734
Code required
0
 
LVL 16

Expert Comment

by:heyhey_
ID: 2663282
:)

I won't post code.
'no homework zone'.
0
 

Accepted Solution

by:
aniket040700 earned 100 total points
ID: 2693266
well i have done a little modification ie. used the actionListener interface in ur code.

see if this is what u wanted or anything else.



import java.applet.Applet;
import java.awt.event.*;
import java.applet.*;
import java.lang.*;
import java.awt.*;

//Creating a Main class Moving Ball
public class BouncingBall extends Applet implements Runnable, ActionListener
{
      //Variable Initialization  
      int Direction_On_X = 0;    
      int Direction_On_Y = 0;
      int x_position     = 0;      
      int y_position     = 0;
      int oldx_position  = 0;  
      int oldy_position  = 0;
      int Squashed      = 0;
      
      //For movemnt Calculation
      Button B1;
      Button B2;
      double gravity         = 9.83;
      double dist            = 0.0;
      double velocity        = 0.0;  
      double BouncingFactor  = 0.4;  
      double Temporaray;
      Double Doublenum;
      String bname;
      
      //Initializing a thread
      Thread thread_Instance;
      
      //Method to squashed the ball
      public void SquashedTheBall()
      {
            Squashed = 1;
            repaint();  
      }

      //Method to beginthe animation , calling by start method
      public void Begin()
      {
            if (thread_Instance == null)
            {
                  thread_Instance = new Thread(this);
                  thread_Instance.start();
            }
      }


      //It will satrt the animation
      public void start()    
      {
            Begin();        
      }
      
      public void run()    
      {
            B1=new Button("+ gravity");
            B2=new Button("- gravity");
            
            add(B1);
            B1.addActionListener(this);
            
            add(B2);
            B2.addActionListener(this);
            
            Thread.currentThread().setPriority(Thread.NORM_PRIORITY);
            while (true)
            {    
                  motion();    
                  try
                  {
                        Thread.sleep(50);    
                  }
                  catch (Exception sleepProblem)
                  {}
            }
      }
      
      public void actionPerformed(ActionEvent e)
      {
            System.out.println("u r in");
            if(e.getSource()==B1)
            {
                  if(gravity>1)
                  {
                  System.out.println("u r in 1");      
                  gravity=gravity+10;
                  }
                  else
                  {
                        gravity=9.81;
                  }
            }
            
            if(e.getSource()==B2)
            {
                  if(gravity>1)
                  {
                        System.out.println("u r in 2");
                        gravity=gravity-10;
                  }
                  else
                  {
                        gravity=9.81;
                  }
            }
      }

      //Painting the ball , normaly and Squashed
      public void paint(Graphics g)  
      {
            g.setColor(getBackground());    
            g.fillOval(oldx_position,oldy_position,40,40);
            g.setColor(Color.red);
            if(Squashed == 1 )
            {
                  g.fillOval(x_position, y_position, 33, 25);
                  Squashed = 0;
            }
            else
            {
                  g.fillOval(x_position, y_position, 40, 40);
            }
      }

      //It will display the ball motion
      private void motion()  
      {
            //Variables updation
            oldx_position = x_position;
            oldy_position = y_position;        
            
            if (Direction_On_Y == 0)
            {
                  //calculate the distance
                  dist = velocity + (1/2)*gravity;    
                  
                  //Calculate the velocity
                  velocity = velocity + gravity;      
                  //Calculate Y posiiton
                  y_position+=(int)dist/10;
                  //If ball reached bottom
                  if (y_position > 300)
                  {
                        SquashedTheBall();
                        Direction_On_Y = 1;                    
                        
                        //Adjust for going below 390...  
                        dist = y_position - 300;
                        velocity = Math.sqrt((velocity*velocity) -  2*gravity*dist);
                        Temporaray = velocity * (BouncingFactor/50);  //Calculate the new velocity because of collision.      
                        velocity = velocity - Temporaray;        
                        y_position = 300;
                  }
            }

            //If Ball is bouncing up, do calculations and adjust y_position accordingly

            else
            {
                  
                  if(velocity <= 0)
                  {
                        Direction_On_Y = 0;
                  }
                  else
                  {
                        dist = velocity + (1/2)*(gravity);
                        velocity = velocity - gravity;      
                        y_position -= dist/20;
                  }

                  
                  if(y_position <= 0)
                  {
                        Direction_On_Y = 0;
                        y_position = 0;
                  }

            }
            //If ball is moving on right hand
            if (Direction_On_X == 0)
            {  
                  //Move the ball by the factor of 2
                  x_position+=2;
                  
                  if (x_position > 800)
                  {
                        // If it is opposite
                        Direction_On_X = 1;
                        x_position = 390;
                  }
            }
            else
            {
                  x_position-=2;

                  if (x_position <= 0)
                  {  
                        Direction_On_X = 0;
                        x_position = 0;
                  }
            }
            repaint();  
      }
      
      
      
}

//from redgreenred
0
 

Author Comment

by:redgreenred
ID: 2696701
thanks
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

For beginner Java programmers or at least those new to the Eclipse IDE, the following tutorial will show some (four) ways in which you can import your Java projects to your Eclipse workbench. Introduction While learning Java can be done with…
Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
Viewers learn about the “while” loop and how to utilize it correctly in Java. Additionally, viewers begin exploring how to include conditional statements within a while loop and avoid an endless loop. Define While Loop: Basic Example: Explanatio…
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Down…

895 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

19 Experts available now in Live!

Get 1:1 Help Now