The names dx and dy implies that those variables should be the change in x and change in y, not the new x and y values. For example is x is 100, and dx is 10, then the new x value would be 110. How would you do this in code, what change do you need to make?
Also, you make int x and int y as local variables. This means that when the method ends, those x and y values will no longer exist - they are local to the method. Instead, you need to save it in a class level variable so you can use it later. What class-level variables store the x and y location of the rectangle?