unable to run PyQt4 example

Question

I am trying to run a pyqt4 example through Notepad++. I asked this question earlier ( Nothing happens when running PyQt4 example code ), and ended up uninstalling Enthought Canopy and all remnants of python and installing cygwin. Now, when I run the example code I get the following error from npp's console. nppExec command --> C:\\cygwin\\bin\\python2.7.exe -i "$(FULL_CURRENT_PATH)" . The example code is shown all the way at the bottom.

The closest I can get is to start cygwin x (type startx from the bash shell) where I can get the example window to come up, although I am unable to exit out of the window.

I feel like I am in over my head here, I just want to create some simple GUI's and I am struggling just to get an example to work. Does Cygwin's python installation lack the classic IDLE?

C:\cygwin\bin\python2.7.exe -i "C:\Users\Brian\Dropbox\Python\PYqt_practice.py"
Process started >>>
cygwin warning:
  MS-DOS style path detected: C:\Users\Brian\Dropbox\Python\PYqt_practice.py
  Preferred POSIX equivalent is: /cygdrive/c/Users/Brian/Dropbox/Python/PYqt_practice.py
  CYGWIN environment variable option "nodosfilewarning" turns off this warning.
  Consult the user's guide for more details about POSIX paths:
    http://cygwin.com/cygwin-ug-net/using.html#using-pathnames
C:\Users\Brian\Dropbox\Python\PYqt_practice.py: cannot connect to X server 
<<< Process finished. (Exit code 1)
================ READY ================

PyQt4 example code

import sys
from PyQt4 import QtGui


def main():

    app = QtGui.QApplication(sys.argv)

    w = QtGui.QWidget()
    w.resize(250, 150)
    w.move(300, 300)
    w.setWindowTitle('Simple')
    w.show()

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

Answer 1

PyQT4 and PyQT5 installed with Cygwin emulate directly what their equivalent Linux packages do, meaning they do expect you to run an X server. Packages dedicated to Windows obviously don't.

Basically you have two choices:

1. Give up on Cygwin and use packages dedicated to Windows, that don't need X server. (You could also run non-Cygwin python in Cygwin environment, but that's going to cause you some headaches, for example with Unicode.)

2. Install X server for Cygwin like this:

   1. Get xorg-server package
   2. Run startx

   If this causes you problems, try:

   2. Run xwin -multiwindow instead of startx

   Now an icon should appear in your tray.

   3. Click it with right mouse button
   4. Hover to "applications"
   5. Click xterm .

   Congratulations! You just ran an xterm shell in X environment. See if your application works now.