title: I want to create a drag and drop application in flutter
body: <p>I have posted a GIF that's states my problem.
  I want to place any draggable at any dragTarget.
  I don't know how to do it. I know the problem lying in this code. This was simply done while experimenting i don't know how to fix this. Please Help.</p>
  <p><a href="https://i.stack.imgur.com/fSRAi.gif" rel="nofollow noreferrer">Here is the gif for refrence</a></p>