Update GUI from event in python + QT

Question

on a raspberry PI running raspbian i am using python + QT (PyQt4)

i am trying to display a value from an interrupt event when a gpio input change his state. Here is the python code :

#!/usr/bin/env python
import RPi.GPIO as GPIO
import time
import os
import random
import datetime
import sys
from threading import Thread

from PyQt4 import QtCore, QtGui, uic


qtCreatorFile = "form.ui" # Enter file here.
global Ui_MainWindow, QtBaseClass 
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)
GPIO.setmode(GPIO.BCM)

GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

global Start

Tmp = datetime.datetime(2000,12,14) 
Start = Tmp.today()   
print str(Start)

def my_Start(channel): #Interrupt 18

   Tmp = datetime.datetime(2000,12,14)  
   Start = Tmp.today()   


def my_Stop(channel): #Interrupt 24
    Tmp = datetime.datetime(2000,12,14)
    Stop = Tmp.today()   
    print str(Stop-Start)
    self.label.setText(str(Stop-Start))





GPIO.add_event_detect(18, GPIO.FALLING, callback=my_Start,bouncetime=2000)
GPIO.add_event_detect(24, GPIO.RISING, callback=my_Stop,bouncetime=2000)
class MyApp(QtGui.QMainWindow, Ui_MainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        Ui_MainWindow.__init__(self)
        self.setupUi(self)
        self.lcdNumber.display(10.1)





if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    window = MyApp()
    window.show()
    sys.exit(app.exec_())

The problem and that self isn't recognize in my_stop callback. So my question : How can i update my GUI from this callback.

Thanks

EDIT

With the answer below it works The only things to modify are :

• Move the Def my_start and my_stop to the GUI class

• define them like that :

  def my_Start(self,channel): 
  def my_Stop(self,channel):
  

• Declare the event like that :

  if __name__ == "__main__":
      app = QtGui.QApplication(sys.argv)
      window = MyApp()
      GPIO.add_event_detect(18, GPIO.FALLING, callback=window.my_Start,bouncetime=2000)
      GPIO.add_event_detect(24, GPIO.RISING, callback=window.my_Stop,bouncetime=2000)
      window.show()
      sys.exit(app.exec_())
  

Thanks to helpers

Answer 1

You are calling self in a non-member function. There is no self to reference in that context. my_Start and my_Stop should be members of myApp:

class MyApp ...
    def my_Stop(self, channel):
        ...