HSPalm HSPalm - 4 months ago 11
Python Question

'Gui' object has no attribute 'after'

I took my working tkinter code (which only drew window/buttons and so on) and tried to add some code from the approved answer here: python code for serial data to print on window.

The approved answer works by itself with very small modifications, but added to my code I get the error "'Gui' object has no attribute 'after'"

What I don't understand is why the attribute "after" is looked for in class Gui instead of in method process_serial.


from tkinter import *
from tkinter import ttk

import serial
import threading
import queue

class SerialThread(threading.Thread):
def __init__(self, queue):
threading.Thread.__init__(self)
self.queue = queue
def run(self):
s = serial.Serial('COM11',115200)
while True:
if s.inWaiting():
text = s.readline(s.inWaiting())
self.queue.put(text)

class Gui():
def __init__(self, master):
###MAIN FRAME###
mainFrame = Frame(master, width=50000, height=40000)
mainFrame.pack(fill = BOTH, expand = 1)

###LIST FRAME###
listFrame = Frame(mainFrame)
listFrame.pack(side = TOP, fill = BOTH, expand = 1)

self.sensorList = ttk.Treeview(listFrame)

self.sensorList["columns"]=("MAC","Type","Value","Voltage","Firmware","Rate","RSSI")
self.sensorList.column("MAC", width=200, minwidth=200)
self.sensorList.column("Type", width=100, minwidth=100)
self.sensorList.column("Value", width=100, minwidth=100)
self.sensorList.column("Voltage", width=100, minwidth=100)
self.sensorList.column("Firmware", width=100, minwidth=100)
self.sensorList.column("Rate", width=100, minwidth=100)
self.sensorList.column("RSSI", width=100, minwidth=100)
self.sensorList.heading("MAC", text="MAC")
self.sensorList.heading("Type", text="Type")
self.sensorList.heading("Value", text="Value")
self.sensorList.heading("Voltage", text="Voltage")
self.sensorList.heading("Firmware", text="Firmware")
self.sensorList.heading("Rate", text="Rate")
self.sensorList.heading("RSSI", text="RSSI")

self.sensorList.pack(fill = BOTH, expand = 1, pady=5, padx=5)

###TEXT AREA FRAME###
textAreaFrame = Frame(mainFrame)
textAreaFrame.pack(side = TOP, fill = BOTH, expand = 1)

self.textArea = Text(textAreaFrame)
self.textArea.pack(fill = BOTH, expand = 1, pady=5, padx=5)

###INPUT FRAME###
inputFrame = Frame(mainFrame)
inputFrame.pack(side = BOTTOM, fill = X, expand = 0)

self.input = Entry(inputFrame)
self.input.pack(side=LEFT, fill = X, expand = 1, pady=5, padx=5)

self.comboAction = ttk.Combobox(inputFrame)
self.comboAction.pack(side = LEFT, pady=5, padx=5)

self.comboDevice = ttk.Combobox(inputFrame)
self.comboDevice.pack(side = LEFT, pady=5, padx=5)

self.sendButton = Button(
inputFrame, text="SEND", command=mainFrame.quit
)

self.sendButton.pack(side=LEFT,pady=5, padx=5)

#self.button = Button(
# mainFrame, text="QUIT", fg="red", command=mainFrame.quit
#)
#self.button.pack(side=LEFT)

#self.hi_there = Button(mainFrame, text="Hello", command=self.say_hi)
#self.hi_there.pack(side=LEFT)

###AFFIX MINIMUM SIZE OF MAIN WINDOW TO PREVENT POOR SIZING###
master.update()
master.minsize(root.winfo_width(), root.winfo_height())
master.minsize(master.winfo_width(), master.winfo_height())

###SERIAL PORT###
self.queue = queue.Queue()
thread = SerialThread(self.queue)
thread.start()
self.process_serial()

def process_serial(self):
while self.queue.qsize():
try:
self.textArea.delete(1.0, 'end')
self.textArea.insert('end', self.queue.get())
except Queue.Empty:
pass
self.after(100, self.process_serial)



def say_hi(self):
s = self.input.get()
print ("hi there, everyone!" + s)

root = Tk()

gui = Gui(root)

root.mainloop()
root.destroy() # optional; see description below

Answer

The culprit is in this line in the process_serial function:

self.after(100, self.process_serial)

The self variable that is in here refers to the Gui object, not to a tkinter object that has the 'after' function.

There is a mismatch between your code and the code from the linked question. Your class does not extend a tkinter object. The class in the answer extended the tkinter Tk object like so:

class App(tk.Tk):

Thereby inheriting functions from the Tk class.

To solve this for your code, replace self in the process_serial function with a tkinter object, like self.textArea.

self.textArea.after(100, self.process_serial)

Alternatively, you could subclass tk.Tk just like in the linked answer. But I do not see the added benefit here.

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