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Need help with collision

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Joined: 2011-01-22
Points: 0

Hello, I am roughly new to java only working with it for a couple months or so and have started my first major program. It is basically a Ragdoll avalanche type game where you dodge falling objects to win. My trouble is I cant seem to get the Collision working between the falling objects, which are JLabels btw, and the character, which I drew.

The character moves with the mouse and is drawn in its own class. I tried to use a rectangle method where I made a rectangle around the Objects falling and the characters head, which is a rectangle, but I just cant get it to work properly. I am hoping someone can help me figure out this collision problem with my application. I will be posting the classes which i use and hope someone can help me figure this out. Also any suggestions would be helpful.

Also I cant upload all the pictures used but I used 50x50 Png pictures for the falling objects and a png for the background. Once again thanks for any help or advice

The following is the class where the falling objects are created and are moved down the screen with a timer.


// Date    : January, 2011

import javax.swing.*;
import java.awt.*;
import java.util.Random;
import java.awt.event.*;

public class PlayDodgeEm
Random number = new Random();
JFrame Gameframe = new JFrame("Dodge Em Game");
Icon ObjectPicture;
//Creates the array of falling objects.
Icon[] FallingObjects = new Icon[4];
//creates the array that holds how many objects will fall.
JLabel[] CurrentObject = new JLabel[30];
JLabel Score = new JLabel("");
//decleration of multiple varialbes that will be used.
int XPos, YPos;
int ScoreCounter;
int counter = 0;
boolean collide, IsHead;
public Rectangle Head;
public Rectangle Object;
int x1, y1, x2, y2;

PlayDodgeEmPanel pane = new PlayDodgeEmPanel();

public PlayDodgeEm() {

      //Sets the layout of the panel to null.

//Adds the pictures to the array
FallingObjects[0] = new ImageIcon(getClass().getResource("FlowerPot.png"));
FallingObjects[1] = new ImageIcon(getClass().getResource("Anvil.png"));
FallingObjects[2] = new ImageIcon(getClass().getResource("Computer.png"));
FallingObjects[3] = new ImageIcon(getClass().getResource("ToolBox.png"));

//Sets the default operation to close.
Gameframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE  );
//Sets the size of teh screen.
Gameframe.setSize(720, 640);
//Sets resizable to false.
      //Packs the screen to fit.
//Sets the visibility to true.
      //sets gameover to false.
      //Calls the method pick Picture
      //Calls the method XPOsition
//Creates a time with 70 miliseconds intervals and uses the actionListener MovingObjects
Timer t = new Timer (10, MovingObjects);
//starts the timer.


public void AddPicture (){
//This method is used to add the picture to the pane with a randomly set X value.
//Adds the picteur to the pane.
//A try catch statement is used in case of an Index out of bounds exception in the array
}catch(ArrayIndexOutOfBoundsException exception){



//This action listener is called with every tick of the timer which is set to 10 milisecond intervals

ActionListener MovingObjects = new ActionListener()
      public void actionPerformed(ActionEvent evt)

//If the YPos is greater than 600...
         if(YPos > 600){
         //Increment counter
         counter ++;
         //if counter equals 31 ...
         if (counter == 31){
//the frame visibility is set to false
//calls the GAmeoverFrame class;
GameoverFrame GameOver = new GameoverFrame();
         }else {
         //Ypos is reset to -20
         YPos = -20;
         //CAlls method PIck Picture
        //calls method XPosition

//Calsl method AddPicture
//Calls method YPosition

//calls method PictureMove.

PlayDodgeEmDraw SendCords = new PlayDodgeEmDraw(XPos, YPos);


public void PickPicture(){
//This method is used to randomly choose the image of the next falling object
//A ramdom number is generated between 4 and 1
int PicNum = number.nextInt(3 - 0 + 1) + 0;
//ObjectPicture stores the picture randomly chosen
ObjectPicture = FallingObjects[PicNum];
//Adds the chosen picture into the array CurrentObject.
//A try catch statement is used in case of an Index out of bounds exception in the array
CurrentObject[counter] = new JLabel (ObjectPicture);
}catch(ArrayIndexOutOfBoundsException exception){


public void YPosition(){
//This method is used to continuelly change the YPos variable which is used to for the Y Position of the picture
//Increments the YPos variable by 10.
YPos = YPos + 20;
public void XPosition(){
//This method is used to randomly assigne the XPos variable with a value.
//XPos is set to a random value between 700 and 1.
XPos = number.nextInt(600 - 1 + 1) + 1;
//Xpos is then added by 20 to create a space.
XPos = XPos + 20;

public void PictureMove(){
//This method is used to move the picture on the screen with teh specified Xpos and YPos variables.

//Sets the new bounds of the current picture.
//A try catch statement is used in case of an Index out of bounds exception in the array
try {
CurrentObject[counter].setBounds(XPos, YPos, 50, 50);
}catch (ArrayIndexOutOfBoundsException exception){


public void AddScore(){
//This method is used to add the users score each time an object goes off the screen.
//Removes the previous score label to be replaced with the new updated one.
//The score counter is incremented.
ScoreCounter ++;
//tempScore takes the string value of the scoreCOunter to be used in a JLabel.
String tempScore = String.valueOf(ScoreCounter);
//Makes the JLAbel that will show the user their score.
Score = new JLabel ("SCORE : " + ScoreCounter );
//Sets the font of the score label.
Score.setFont(new Font("Comic Sans MS", Font.BOLD,20));
//Sets teh colore of teh score label.
//Sets the bounds of the label to be in the upper right corner.
Score.setBounds(600, 10, 200, 100);
//Adds the score the the panel.
//calls repaint method for the score.


The following is the class where I draw the charachter


// Data : January, 2011

// imports java package
import java.awt.*;

// public clas PlayDodgeEmDraw
public class PlayDodgeEmDraw
// declares variables
   public int x, y, PicX, PicY;
Rectangle ObjRect;
Rectangle Head;
boolean collide = false;
   public final int WIDTH = 40, HEIGHT = 20;
// open constructor
public PlayDodgeEmDraw(){

// constructor that takes in paramaters
public PlayDodgeEmDraw(int PicXRec,int PicYRec){
// variable "PicX" = parameter
PicX = PicXRec;
      // variable "PicY" = parameter
      PicY = PicYRec;
// creates new rectangle with the x and y parameters
ObjRect = new Rectangle(PicX, PicY, 50,50);


   public void move(int xPos, int yPos)
    // finds x position of mouse
      x = xPos;
  // finds y position of mouse
      y = yPos;


// draw method for the avatar ( stick man)
   public void draw(Graphics OBJ, int screenWidth)
// creates new variable named "baseX" which will equal the x coordinate from another method - variable "WIDTH"
      int baseX = x - WIDTH;
// creates new variable named "baseY" which will equal the y coordinate from another method - variable "HEIGHT" / 2
      int baseY = y - HEIGHT/2;

// creates a new rectangle with the head coordinates
Head = new Rectangle(baseX - 10, baseY, 75,50);

//sends head (rectangle) to collision method

// draws head
OBJ.fillRect(baseX - 10, baseY, 75,50);
// color set to yellow
// draws left eye
OBJ.fillOval(baseX + 12, baseY + 10, 10 ,10);
// draws right eye
OBJ.fillOval(baseX + 32, baseY + 10, 10 ,10);
// draws smile
OBJ.fillArc(baseX + 13, baseY + 30,  25,  8,  170, 190);
// color set to black
// draws stick body
OBJ.drawLine(baseX + 25, baseY + 50, baseX + 25, baseY + 70);
// draws left leg
OBJ.drawLine(baseX +24, baseY + 70, baseX + 10, baseY + 90);
// draws right leg
OBJ.drawLine(baseX +38, baseY + 90, baseX + 24, baseY + 70);
// draws arms (with one line)
OBJ.drawLine(baseX +10, baseY + 60, baseX + 40, baseY + 60);


// our collision  method (which doesn't work properly)
   public void Collision(Rectangle Head) {

collide = Head.intersects(ObjRect);

if (Head.intersects(ObjRect)) {

System.out.println("Collision : true");




And finally the panel for the game and also the MouseListeners to move the charachter


// Data : January, 2011

// imports java packages
import java.awt.*;

import javax.swing.*;

import java.awt.event.*;
// public class "PlayDodgeEmPanel" extends the JPanel
public class PlayDodgeEmPanel extends JPanel
// calls public PlayDodgeemDraw
public PlayDodgeEmDraw PlayDodgeEmDraw;
// private Image variables are declared.
    private Image image1;
private Image currentImage;

   public PlayDodgeEmPanel()
    // variable "Image1" will equal background picture
     image1 = (new ImageIcon("GameBackground1.png")).getImage();
    // variable "currentimage" will equal "Image1"
    currentImage = image1;
     PlayDodgeEmDraw = new PlayDodgeEmDraw();
// declares new listener called "monitor"
      AvatarListener monitor = new AvatarListener();
      // Mouse motion listner is added to our listener named "monitor"
      // Mouse listner is added to our listener named "monitor"

//Background color will be black if no picture is displayed
      setBackground (;
     // Preferred size of panel is 800 x 600
      setPreferredSize(new Dimension(800, 600));

// calls graphical paint component method
   public void paintComponent(Graphics page)
    // uses super class
     // panel will draw the background image
      page.drawImage(currentImage, 0, 0, null);
     // sends information to the draw method of "PlayDodgeEmDraw"
      PlayDodgeEmDraw.draw(page, getWidth());


// public class avatar listner will implement bouth the mouse motion and mouse listneners (monitor)
   public class AvatarListener implements MouseMotionListener, MouseListener
// public method for when the mouse is moved declared
      public void mouseMoved(MouseEvent event)
       // calls and sends info to PlayDodgeEmDraw (x and y coords)
         PlayDodgeEmDraw.move(event.getX(), event.getY());
       // repaints

// public method for when the mouse is dragged
      public void mouseDragged(MouseEvent event)
        // calls and sends info to PlayDodgeEmDraw (x and y coords)
        PlayDodgeEmDraw.move(event.getX(), event.getY());
       // repaints
// unused mouse method
public void mousePressed(MouseEvent event)

// unused mouse method
public void mouseReleased(MouseEvent event)

// unused mouse method
public void mouseClicked(MouseEvent event)


// unused mouse method
      public void mouseEntered(MouseEvent event) {}
// unused mouse method
  public void mouseExited(MouseEvent event) {}


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Joined: 2008-04-17
Points: 0

Unfortunately I was not able to compile and run your code straight away (for example, it doesn't seem to have a main method) However, it seems to me that the problem is the way that you've organised your objects. PlayDodgeEmDraw is (or I think that's what you intend) the player object, so it should know where itself is (this is your variable Head), then you need to call your Collision method from PlayDodgeEm, passing in the rectangles of all the falling objects. i.e in pseudo code
for all falling objects {
playdodgemdraw.Collision(falling object);
and Collision looks like

void Collision(Rectangle other)
if (Head.intersects(other)) {

Also, you don't need to destroy and recreate the Score label every time(create and position it at the start , then call setText() on it) And, I would recommend not using labels for the falling objects, just make your own class with an Image and a Rectangle and draw these when you draw the player.
Hope that helps, Pete