如何在Java中移动矩形？

Question

I am trying to move a rectangle but I am not sure how to do it, I know it something to do with 'mouseClicked(MouseEvent e)` but don't know how to use it. This is the code I have so far:

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class MovRect extends Applet implements MouseMotionListener, MouseListener {
Color color = Color.green;
int x=30,y=30,w=150,l=150;
String MouseMotion ="";

public void init()
{
    addMouseListener(this);
    addMouseMotionListener(this);
}
public void paint(Graphics g)
{
    super.paint(g);

    g.setColor(color);
    g.drawRect(x, y, w, l);

}
public void mouseClicked(MouseEvent e)
{
    String clickDesc;
    if (e.getClickCount() == 2)
        clickDesc = "double";
    else
        clickDesc = "single";

    System.out.println("Mouse was " + clickDesc + "-clicked at location (" +
        e.getX() + ", " + e.getY() + ")");

        int mouseX = e.getX();
        int mouseY = e.getY();

    if( mouseX >= x && mouseX <= x+w && mouseY >= y && mouseY <= y+l )
    {

    }
    else
    {

    }
        this.repaint();
}

public void mouseDragged(MouseEvent e)
{
    System.out.println("mouse is being dragged at location (" + e.getX() + ", " +      e.getY() + ")");
    MouseMotion ="mouseDragged";
    repaint();
}
public void mouseMoved(MouseEvent e)
{
    System.out.println("mouse is being moved at location (" + e.getX() + ", " + e.getY() + ")");
    MouseMotion ="mouseMoved";
    repaint();
}


public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
 }

Answer 1

New answer If you want to be able to click and drag the rectangle you just basically update the x and y of the rectangle and have a mouse listener change those values to the mouses current position on click.

Old Answer

Your question is a little confusing. You mention using mouseClicked(MouseEvent e) yet that hasing nothing to do with actually moving the rectangle that deals with a event where the mouse is clicked.

If you just want to move your rectangle you could have a variable and add to the x or y. For Example:

 int x = 100; int y = 100; g.fillRect(x,y,100,100); 

Then in your public void run you could do:

  try { Thread.sleep(100); }catch(Exception e) { } x = x + 2; y = y +2; repaint(); 

Or for if the mouse was clicked basically you'd be using the mouse event and when it's clicked you would just set that x and y to the mouse's position.

Answer 2

If you want to be able to 'paint' rectangles this snipet works nicely.

public int XVal = 0 , YVal = 0;

public void paint(Graphics g) {

    g.fillRect(XVal, YVal, 20, 20);

    addMouseMotionListener(
            new MouseMotionAdapter() {

                public void mouseDragged(MouseEvent e) {

                    XVal = e.getX();
                    YVal = e.getY();
                    repaint();
                }
            });
} 

Answer 3

In order to have it move sequentially, you need to get the relative position which is always currentPosition - LastPosition. You could store the current position using mouseMove.

public void mouseMoved(MouseEvent e)
{
  _relativePosition.x = e.getX() - _currentPosition.x;
  _relativePosition.y = e.getX() - _currentPosition.y;
  _currentPosition.x = e.getX();
  _currentPosition.y = e.getY();
}

Answer 4

你只需要在tick方法（）中增加x或y变量;

Answer 5

You need to add the mouse listener to the object you want to listen. Check out http://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html it will get you started on how to set up the mouse listener.
Also where are you actually stuck? Getting the listener to work? Or getting the rectangle to move?