Drag and drop of a 2D diagram ??

Question

Hello
Iam using JPanel for the drawing area container.I want the following functionality:
When I click and release a button I must be able to draw a diagram ( circle ,square etc)
How can I do this
Thanks in advance

Answer 1

I am working on a similar project.
Using canvas instead of a JPanel might be a more proper choice.
You add a mouse listener to the canvas, which returns the coordinates of the click occured. See the documentation,
the code goes something like this:
yourCanvas.addMouseListener(new MouseAdapter(Event evt)
                            public void mouseClicked(MouseEvent e)
                        System.out.println("Mouse click occured");
                          });MouseAdapter is an interface, see the docs, which methods it declares. One of the methods is mouseClicked(), which you have to override to perform actions you wish.
To draw a rectangle, you got to use:
Graphics g = yourCanvas.getGraphics();
g.drawRect(int x,int y,int width, int height);See Graphics or Graphics2D in the docs to be aware what possibilities for drawing you have.
For better understanding use the tutorials, e.g. BufferedShapeMover.java on http://java.sun.com.
I hope this helped a little.
I have similar proble with MOVING the objects I have drawn, I still use to repaint or updated the canvas, together with the mouse listeners. This seem not very clever to me, but I didn't find any component, which could be placed to a container and dragged with a mouse.
good luck