Python-сообщество

 directory = "C:\Folder1\Folder2\Folder3"
self.QDir(directory).direcrion.entryList().countChanged.connect(self.MyFunction)

 import sys
from PyQt5 import QtWidgets
from PyQt5.QtCore import QDir, QTimer
import Testwin_1
folder = r"C:\######\########\#########\Myfolder"
list = []
class Testing_1(QtWidgets.QMainWindow, Testwin_1.Ui_MainWindow):
    def __init__(self):
        super().__init__()
        self.setupUi(self)
        self.setWindowTitle("Testing")
        self.init_UI()
    def init_UI(self):
        global list
        direcrion = QDir(folder)
        templist = direcrion.entryList()
        for file in templist:
            if "." in file:
                if file.split(".")[len(file.split("."))-1].lower() == "xls":
                    list.append(file)
        self.timer = QTimer()
        self.timer.timeout.connect(self.Refresh)
        self.timer.start(5000)
    def Refresh(self):
        global list
        direcrion = QDir(folder)
        templist = direcrion.entryList()
        for file in templist:
            if "." in file:
                if file.split(".")[len(file.split("."))-1].lower() == "xls":
                    if not file in list:
                        print("Новый XML: ",file)#########Вместо этой функции будут функции обработки данного файла
                        list = templist
                        break
        self.timer.start(5000)
def main():
    app = QtWidgets.QApplication(sys.argv)
    window = Testing_1()
    window.show()
    sys.exit(app.exec_())
if __name__ == "__main__":
    main()

 fs_watcher = QFileSystemWatcher(['C:\\Folder'])
fs_watcher.directoryChanged.connect(self.directory_changed)

 import sys
from PyQt4 import QtGui
from PyQt4 import QtCore
folder = 'd:\\TEMP'
def folder_event(string):
    print(string)
app = QtGui.QApplication(sys.argv)
mw= QtGui.QWidget()
mw.show()
fs_watcher = QtCore.QFileSystemWatcher([folder,])
fs_watcher.directoryChanged.connect(folder_event)
sys.exit(app.exec_())

 import sys
from PyQt5 import QtCore
from PyQt5.QtWidgets import QApplication, QWidget
folder = 'd:\\TEMP'
def folder_event(string):
    print(string)
app = QApplication(sys.argv)
mw = QWidget()
mw.show()
fs_watcher = QtCore.QFileSystemWatcher([folder,])
fs_watcher.directoryChanged.connect(folder_event)
sys.exit(app.exec_())