change the mouse cursor - crosshair cursor

[cassysumandak]

I developed a program to draw polygon triangles. The triangles were drawn using mouse drag. The coordinate of the triangles were stored in array list. Every times the mouse cursor, mouse over on the existing drawn triangles(within the area of triangles), the mouse cursor should turns to "CROSSHAIR_CURSOR", however this was not happened. Help :-(

...
    public class DrawingBoardWithMatrix extends JFrame {
      public static void main(String[] args) {
        new DrawingBoardWithMatrix();
      }

    public DrawingBoardWithMatrix(){  
      this.add(new PaintSurface(), BorderLayout.CENTER);
      ... 
    }

    private class PaintSurface extends JComponent {
      java.util.List<Polygon> triangles = new LinkedList<Polygon>();
      Point startDrag, endDrag, midPoint;
      Polygon triangle;

      public PaintSurface() {   
      ... 
      this.addMouseListener(new MouseAdapter() {
        public void mousePressed(MouseEvent e) {
          startDrag = new Point(e.getX(), e.getY());
          endDrag = startDrag;
          repaint();
        }//end mousePressed   

        public void mouseReleased(MouseEvent e) {
          if (startDrag.x > endDrag.x)
            midPoint = new Point((endDrag.x +(Math.abs(startDrag.x - endDrag.x)/2)),e.getY());
          else 
           midPoint = new Point((endDrag.x -(Math.abs(startDrag.x - endDrag.x)/2)),e.getY()); 

          int[] xs = { startDrag.x, endDrag.x, midPoint.x };
          int[] ys = { startDrag.y, startDrag.y, midPoint.y };      
          triangles.add( new Polygon(xs, ys, 3));    

          startDrag = null;
          endDrag  = null;
          repaint();
        }//end mouseReleased              
      });//end addMouseListener

      this.addMouseMotionListener(new MouseMotionAdapter() {
        public void mouseDragged(MouseEvent e) {
          endDrag = new Point(e.getX(), e.getY());
          repaint();
        }//end mouseDragged     

    //THIS CODE DOESNT WORK - AND I AM STUCK :-(       
    public void mouseMoved(MouseEvent e) {
      startDrag = new Point(e.getX(), e.getY());
      if (triangles.contains(startDrag))
         setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
      else
         setCursor(Cursor.getDefaultCursor());
    }// end mouseMoved

      });//end this.addMouseMotionListener
    }//end paintSurface       

     private void paintBackground(Graphics2D g2){
     ...
     }

     public void paint(Graphics g) {
     ...
     }

    }//end private class PaintSurface

    }//end public class DrawingBoardMatrix

[cassysumandak]

Never mind, the problem has been solved.

    		public void mouseMoved(MouseEvent e) {
    		      startDrag = new Point(e.getX(), e.getY());
    		      Cursor cursor = Cursor.getDefaultCursor();
    		      //you have a List<Polygon>, so you can use this enhanced for loop
    		      for (Polygon p : triangles) { 
    		        if (p.contains(startDrag)) {//Polygon has a 'contains(Point)' method
    		           cursor = Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
    		           break; //you've found a hit, break from the loop 
    		        }
    		      }
    		      setCursor(cursor);
    		}