title: how to create folder view in pyqt inside main window
body: <p>I'm trying to implement a folder viewer to view the structure of a specific path. and this folder view should look like a the tree widget in PyQT , i know that the file dialog can help , but i need to have it inside my main window.
  <br>
  i tried to implement this using QTreeWidget and i used a recursed function to loop inside folders, but this is too slow. since it needs to recurse around huge number of folders.
  is this the right way to do it? or there is a ready qt solution for this problem.
  <br>
  Check the figure below.</p>
  
  <p><br>
  <img src="https://i.stack.imgur.com/ULi6C.jpg" alt="enter image description here"></p>