gistfile1.py

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.Qsci import QsciScintilla, QsciLexerPython
import os
import os.path

class Editor(QsciScintilla):

    def __init__(self, parent=None):
        super(Editor, self).__init__(parent)
        self.mtime = 0

        font = QFont()
        font.setFamily('Courier')
        font.setFixedPitch(True)
        font.setPointSize(10)
        self.setFont(font)
        self.setMarginsFont(font)
        
        lexer = QsciLexerPython()
        lexer.setDefaultFont(font)
        self.setLexer(lexer)
        self.SendScintilla(QsciScintilla.SCI_STYLESETFONT, 1, 'Courier')
        self.SendScintilla(QsciScintilla.SCI_SETHSCROLLBAR, 0)
        self.setMinimumSize(600, 450)

    def focusInEvent(self, e):
        if (not os.path.exists(self.path)) or
            (self.mtime == os.path.getmtime(self.path)):
            return

        self.printStuff(pathfile)

        QsciScintilla.focusInEvent(self, e)

    def printStuff(self, path):
        self.path = path
        self.mtime = os.path.getmtime(self.path)
        self.setText(open(self.path).read())
        print 'File reloaded'

if __name__ == "__main__":
    app = QApplication(sys.argv)
    editor = Editor()
    editor.printStuff(r'C:\Temp\test.py').read())
    editor.show()
    app.exec_()