Dragging Boxes

I can't drag my boxes using MouseMotionListener, helps are appreciated.

Code:

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class DragingBoxesPanel extends JPanel implements MouseListener, MouseMotionListener{
       
        private boolean dragging;
        private int whichBox;                        // 0: RED, 1: BLUE 2: NONE
        private int lastBox;
        private int redX;
        private int redY;
        private int blueX;
        private int blueY;
//...

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Code:

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public void paintComponent(Graphics g) {
// ...
                g.setColor(Color.RED);
                g.fillRect(redX,redY,50,50);
                g.setColor(Color.BLUE);
                g.fillRect(blueX,blueY,50,50);

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Code:

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        public void mousePressed(MouseEvent evt) {
               
                int x = evt.getX();
                int y = evt.getY();
               
                if(evt.isShiftDown()) {
                        redX = 5;
                        redY = 5;
                        blueX = 75;
                        blueY = 5;
                        repaint();
                }
               
                else {
                       
                        if((x>=redX && x<=redX+50 && y>=redY && y<=redY+50) && ((x<blueX || x>blueX+50) && (y<blueY || y>blueY+50))) {
                                whichBox = 0;
                                dragging = true;
                        }
                       
                        else if((x>=blueX && x<=blueX+50 && y>=blueY && y<=blueY+50) && ((x<redX || x>redX+50) && (y<redY || y>redY+50))) {
                                whichBox = 1;
                                dragging = true;
                        }
                       
                        else if(x>=redX && x<=redX+50 && y>=redY && y<=redY+50 && x>=blueX && x<=blueX+50 && y>=blueY && y<=blueY+50) {
                                whichBox = 0;
                                dragging = true;
                        }
                       
                        else {
                                whichBox = 2;
                        }
                }
        }

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Code:

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public void mouseReleased(MouseEvent evt) {
                dragging = false;
        }

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Code:

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public void mouseDragged(MouseEvent evt) {
               
                if(!dragging) return;
               
                int x = evt.getX();
                int y = evt.getY();
               
                if(whichBox == 0) {
                        redX = x;
                        redY = y;
                        repaint();
                }
                else if(whichBox == 1) {
                        blueX = x;
                        blueY = y;
                        repaint();
                }
                else { };
               

               
        }

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Code:

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public DragingBoxesPanel() {
                setBackground(Color.WHITE);
                addMouseListener(this);
                addMouseMotionListener(this);
                redX = 5;
                redY = 5;
                blueX = 75;
                blueY = 5;
                whichBox = 0;
                dragging = false;
        }

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You may wish to post a small compilable program so we can test it out and see what is not working.

If I were to do this, I'd create a class called Box or SimpleBox that encapsulates all the characteristics of a box. Something like:

Code:

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public class SimpleBox {
  private int x;
  private int y;
  private int width;
  private int height;
  private Color color;
 
  // constructors setters and getters go here

  // the box can paint itself
  public void paint(Graphics g) {
      g.setColor(color);
      g.fillRect(x, y, width, height);
  }

  // can check if it contains x & y.  Can also overload this and check
  // if it contains a Point
  public boolean contains(int x2, int y2) {
      // code to check if contains
  }
 
  public void move(int x, int y) {
      this.x = x;
      this.y = y;
  }

}

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Then the DragBoxPanel can contain a collection of SimpleBoxes, and its paintcomponent method
can simply ask the boxes to draw themselves:

Code:

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public class DragBoxPanel extends JPanel{
  private List<SimpleBox> boxes = new ArrayList<SimpleBox>();

  protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      for (SimpleBox box : boxes) {
        box.paint(g);
      }
  }

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Actually I'm learning java from web, and I don't know arrays yet.

Here's DragingBoxesPanel (yea, it shoud've been Dragging-)

rapidshare . com/files/276083966/DragingBoxesPanel.java

There's no error actually, just the boxes don't move.

Quote:

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Originally Posted by anilanar

Actually I'm learning java from web, and I don't know arrays yet.

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Don't you think that you may be getting the cart before the horse if you're trying to learn complex GUI programming before learning basic Java? You may be setting yourself up for much disappointment by doing this. Just a thought.

I've been reading and doing exercises from the start of this page: math.hws.edu/javanotes
You can check there and share your thoughts if you want :)

I'll be danged -- they list GUI programming before they talk about arrays! Well go for it, but I have to admit that it seems a bit backwards to me.

Anyway, I just found what's wrong:

Code:

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if((x>=redX && x<=redX+50 && y>=redY && y<=redY+50) && ((x<blueX || x>blueX+50) && (y<blueY || y>blueY+50))) {
                                whichBox = 0;
                                dragging = true;
                        }

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that was wrong I should've done :

Code:

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if((x>=redX && x<=redX+50 && y>=redY && y<=redY+50) && [B]((x<blueX || x>blueX+50) || (y<blueY || y>blueY+50))[/B]) {
                                whichBox = 0;
                                dragging = true;
                        }

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I'm just a 2-3 sections away from arrays, so I'll learn them soon. Thank you :)

You're welcome. Just for grins, here's an ArrayList way to do it:

SimpleBox.java

Code:

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import java.awt.Color;
import java.awt.Graphics;

public class SimpleBox {
  private int x;
  private int y;
  private int width;
  private int height;
  private Color color;
 
  public SimpleBox(int x, int y, int width, int height, Color color) {
      this.x = x;
      this.y = y;
      this.width = width;
      this.height = height;
      this.color = color;
  }
  public int getX() {
      return x;
  }
  public void setX(int x) {
      this.x = x;
  }
  public int getY() {
      return y;
  }
  public void setY(int y) {
      this.y = y;
  }
  public int getWidth() {
      return width;
  }
  public void setWidth(int width) {
      this.width = width;
  }
  public int getHeight() {
      return height;
  }
  public void setHeight(int height) {
      this.height = height;
  }
  public Color getColor() {
      return color;
  }
  public void setColor(Color color) {
      this.color = color;
  }
 
  public void paint(Graphics g) {
      g.setColor(color);
      g.fillRect(x, y, width, height);
  }
 
  public boolean contains(int x2, int y2) {
      if (x2 >= x && x2 <= x + width && y2 >= y && y2 <= y + height) {
        return true;
      } else {
        return false;
      }
  }
 
  public void deltaMove(int deltaX, int deltaY) {
      x += deltaX;
      y += deltaY;
  }
 
  public void move(int x, int y) {
      this.x = x;
      this.y = y;
  }

}

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DragBoxPanel.java

Code:

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import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.swing.*;

@SuppressWarnings("serial")
public class DragBoxPanel extends JPanel {
  private static final Color[] COLORS = {
      Color.black, Color.white, Color.red, Color.orange, Color.yellow,
      Color.green, Color.blue, Color.magenta
  };
  private static final int SIDE = 50;
  private static final int MAIN_SIDE = 600;
  private static final Dimension MAIN_SIZE = new Dimension(MAIN_SIDE, MAIN_SIDE);
  private List<SimpleBox> boxes = new ArrayList<SimpleBox>();
  private Random random = new Random();
 
  public DragBoxPanel() {
      setPreferredSize(MAIN_SIZE);
      setBackground(Color.darkGray);
      for (Color color : COLORS) {
        int x = random.nextInt(MAIN_SIDE - SIDE);
        int y = random.nextInt(MAIN_SIDE - SIDE);
        SimpleBox box = new SimpleBox(x, y, SIDE, SIDE, color);
        boxes.add(box);
      }
     
      MyMouseListener mymListener = new MyMouseListener();
      addMouseListener(mymListener);
      addMouseMotionListener(mymListener);
  }
 
  @Override
  protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      for (SimpleBox box : boxes) {
        box.paint(g);
      }
  }
 
  private class MyMouseListener extends MouseAdapter {
      private SimpleBox selectedBox = null;
      private Point delta = null;
     
      @Override
      public void mousePressed(MouseEvent e) {
        selectedBox = null;
        delta = null;
        for (int i = boxes.size() - 1; i >= 0; i--) {
            SimpleBox box = boxes.get(i);
            if (box.contains(e.getX(), e.getY())) {
              selectedBox = box;
              delta = new Point(e.getX() - box.getX(), e.getY() - box.getY());
              return;
            }
        }
      }
     
      @Override
      public void mouseReleased(MouseEvent e) {
        selectedBox = null;
        delta = null;
      }
     
      @Override
      public void mouseDragged(MouseEvent e) {
        if (selectedBox != null) {
            selectedBox.move(e.getX() - delta.x, e.getY() - delta.y);
            DragBoxPanel.this.repaint();
        }
      }
  }
 
  private static void createAndShowUI() {
      JFrame frame = new JFrame("DragBoxPanel");
      frame.getContentPane().add(new DragBoxPanel());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
  }

  public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            createAndShowUI();
        }
      });
  }
}

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