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Thread: Balloon Applet Help [Simple for non-novice]

  1. #1
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    Default Balloon Applet Help [Simple for non-novice]

    The applet allows you to move the balloon in a few directions, keeping the string in the bottom middle of the screen, which works fine. The problem started when I implimented the increase width/height buttons. When I increase the width and height, the balloon then falls through the south and east of the window about 1/2way when you try and push it up against the walls, and I cannot figure out why. Ty for the help.

    Here is the full code:

    package Balloon;
     
    import java.awt.*;
    import java.applet.*;
    import java.awt.event.*;
     
    public class balloon extends Applet
     
    implements ActionListener{   
     
        private static final long serialVersionUID = 1L; 
     
        Button north, west, south, east, northeast, northwest, southeast, southwest, center;
        Button increaseWidth, decreaseWidth, increaseHeight, decreaseHeight;
     
        public int displayWidth = 600;
        public int displayHeight = 600;
        public int boundX = displayWidth-50;
        public int boundY = displayHeight-76;
        public int startX = boundX/2;
        public int startY = boundY/2;
     
        public static final boolean CONSOLE_LOGGING = true;
     
        public void init(){
     
            west = new Button ("West");
            add (west);
            west.addActionListener (this); 
     
            northwest = new Button ("Northwest");
            add (northwest);
            northwest.addActionListener (this); 
     
            northeast = new Button ("Northeast");
            add (northeast);
            northeast.addActionListener (this); 
     
            north = new Button ("North");
            add (north);
            north.addActionListener (this); 
     
            center = new Button ("Center");
            add (center);
            center.addActionListener (this);
     
            south = new Button ("South");
            add (south);
            south.addActionListener (this); 
     
            southwest = new Button ("Southwest");
            add (southwest);
            southwest.addActionListener (this);
     
            southeast = new Button ("Southeast");
            add (southeast);
            southeast.addActionListener (this); 
     
            east = new Button ("East");
            add (east);
            east.addActionListener (this); 
     
            increaseWidth = new Button ("Increase Width");
            add (increaseWidth);
            increaseWidth.addActionListener (this); 
     
            decreaseWidth = new Button ("Decrease Width");
            add (decreaseWidth);
            decreaseWidth.addActionListener (this); 
     
            increaseHeight = new Button ("Increase Height");
            add (increaseHeight);
            increaseHeight.addActionListener (this); 
     
            decreaseHeight = new Button ("Decrease Height");
            add (decreaseHeight);
            decreaseHeight.addActionListener (this); 
     
        } // end Init 
     
        public void paint(Graphics g){
     
        	resize(displayWidth, displayHeight);
            setBackground(Color.BLACK);
            g.setColor(Color.WHITE);
            g.fillOval(startX,startY,50,70);
            g.drawLine(startX+25,startY+70,displayWidth/2, displayHeight);
     
        } //end Paint
     
        public void actionPerformed(ActionEvent click){
     
        		if (click.getSource()== west)
                doWest();
                else if (click.getSource()== northwest)
                doNorthwest();
                else if (click.getSource()== northeast)
                doNortheast();
                else if (click.getSource()== north)
                doNorth();
                else if (click.getSource()== center)
                doCenter();
                else if (click.getSource()== south)
                doSouth();
                else if (click.getSource()== southwest)
                doSouthwest();
                else if (click.getSource()== southeast)
                doSoutheast();
                else if (click.getSource()== east)
                doEast();
                else if (click.getSource()== increaseWidth)
                doincreaseWidth();
                else if (click.getSource()== decreaseWidth)
                dodecreaseWidth();
                else if (click.getSource()== increaseHeight)
                doincreaseHeight();
                else if (click.getSource()== decreaseHeight)
                dodecreaseHeight();
     
        		repaint();
     
        		if (CONSOLE_LOGGING)
                    System.out.println(startX + " " + startY);
     
        } //end ActionPerformed
     
        public void doNorth(){
     
            if (startY-10 >= 0)
                startY-=10;
            else
                startY -= Math.abs(0+startY);
        }
        public void doWest(){
     
        	if (startX-10 >= 0)
                startX-=10;
            else
                startX -= Math.abs(0+startX);
        }
        public void doEast(){
     
            if (startX+10 <= boundX)
                startX+=10;
            else
                startX += Math.abs(boundX-startX);
        }
        public void doSouth(){
     
        	if (startY+10 <= boundY)
        		startY+=10;
        	else
        		startY += Math.abs(boundY-startY);
        }
        public void doNorthwest(){
     
        	doNorth();
            doWest();
        }
        public void doNortheast(){
     
            doNorth();
            doEast();
        }
        public void doSouthwest(){
     
            doSouth();
            doWest();
        }
        public void doSoutheast(){
     
            doSouth();
            doEast();
        }
        public void doincreaseWidth(){
     
        	displayWidth += 25;
        	boundX = displayWidth - 25;
     
        }
        public void dodecreaseWidth(){
     
        	displayWidth -= 25;
        	boundX = displayWidth - 25;
     
        }
        public void doincreaseHeight(){
     
        	displayHeight += 25;
        	boundY = displayHeight - 25;
     
        }
        public void dodecreaseHeight(){
     
        	displayHeight -= 25;
        	boundY = displayHeight - 25;
     
        }
        public void doCenter(){
     
        	startX=boundX/2;
            startY=boundY/2;
     
        }
    } //end ActionList


    --- Update ---

    I'm thinking the problem may lie within the increase/decrease height/width methods, but I've tried changing some numbers around and it hasn't helped.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Balloon Applet Help [Simple for non-novice]

    Is this the same problem:
    Simple Balloon Applet [Help!!!]
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Balloon Applet Help [Simple for non-novice]

    Quote Originally Posted by Norm View Post
    Is this the same problem:
    Simple Balloon Applet [Help!!!]
    Same program, different problem. Another thing I noticed is that when you increase or decrease the width or height, and you try and re center the balloon with the center button, the balloon is slightly off to the right.

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Balloon Applet Help [Simple for non-novice]

    Can you add some println statements for debugging that shows the problem?
    For example print out the balls position when it is centered then compare those values with what they should be for the ball to be where you want it to be. You should have manually computed the correct position so you can compare it to what the program computes.
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: Balloon Applet Help [Simple for non-novice]

    Fixed it, the problem was here:
     public void doincreaseWidth(){
     
        	displayWidth += 25;
        	boundX = displayWidth - 25;
     
        }
        public void dodecreaseWidth(){
     
        	displayWidth -= 25;
        	boundX = displayWidth - 25;
     
        }
        public void doincreaseHeight(){
     
        	displayHeight += 25;
        	boundY = displayHeight - 25;
     
        }
        public void dodecreaseHeight(){
     
        	displayHeight -= 25;
        	boundY = displayHeight - 25;

    I had to change the 25's to match the width and height of the balloon, like this:
     public void doincreaseWidth(){
     
        	displayWidth += 25;
        	boundX = displayWidth - 50;
     
        }
        public void dodecreaseWidth(){
     
        	displayWidth -= 25;
        	boundX = displayWidth - 50;
     
        }
        public void doincreaseHeight(){
     
        	displayHeight += 25;
        	boundY = displayHeight - 70;
     
        }
        public void dodecreaseHeight(){
     
        	displayHeight -= 25;
        	boundY = displayHeight - 70;
     
        }

    Thank's for your help though guys!

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