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Local variable referenced before assignment (TKINTER)

I'm getting an UnboundLocalError
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.1264.0_x64__qbz5n2kfra8p0\lib\tkinter\__init__.py", line 1921, in __call__
return self.func(*args)
File "C:\Users\Ya Bish\Projects\Obracun Sati\main.py", line 249, in item_selected
app = EmpWindow(top,record)
UnboundLocalError: local variable 'record' referenced before assignment
when asking for filename and
def __init__(self,master):
self.master = master
self.openButton = Button(self.frame, text="Open",
command=self.openFile)
...
self.tree = Treeview(self.master, columns=self.columns, show="headings")
...
self.tree.bind('<<TreeviewSelect>>', self.item_selected)
def openFile(self):
...
self.tree.delete(*self.tree.get_children())
filename = filedialog.askopenfilename()
calc(filename)
for e in emps:
self.tree.insert('', END, values=e.treeValues)
while this Toplevel() window is either active or have been previously active.
def item_selected(self, event):
for selected_item in self.tree.selection():
item = self.tree.item(selected_item)
record = item['values'][0]
top = Toplevel()
app = EmpWindow(top,record)
top.mainloop()
EmpWindow is just a notebook class with two tabs defined and couple of labels so I don't think that code is necessary.
This may be an error with event and Bind but I don't understand that part at all so I don't even know how to approach it.

This might be happening because your for-loop in item_selected is not even getting a single iteration in which case record will never be defined. A simplified version of this is the following
def f():
for x in range(0):
print(x)
print(x)
f()
This gives the exact same error as your code. This kind of error occurs whenever you reference a variable before you assign it inside functions.

Calling an object method using a function

I am playing around tkinter, and I was wondering if I had declared a method within an object, can I call it using the 'protocol' method of tkinter? or any function to be exact ie.
class Notepad():
...
...
def exit_func():
#Messagebox command warning 'You are exiting'
root = tk.Tk()
notepad = Notepad(root)
root.geometry("800x500")
root.mainloop()
#Problem is here
root.protocol("WM_DELETE_WINDOW", app.exit_func())
I tried this with my program, where my 'exit_func' had a 'get' function from tkinter and i got this error:
Traceback (most recent call last):
File "Notepad_with_console.py", line 204, in <module>
root.protocol("WM_DELETE_WINDOW", notepad.exit_file())
File "Notepad_with_console.py", line 175, in exit_file
if self.text.get(1.0,tk.END) != '' and self.current_file_dir == '':
File "C:\Anaconda\lib\tkinter\__init__.py", line 3246, in get
return self.tk.call(self._w, 'get', index1, index2)
_tkinter.TclError: invalid command name ".!text"
Is there a reason for this? Thanks!

root.protocol requires a reference to a function. Instead, you're immediately calling a function and then passing in the result.
Consider this code:
root.protocol("WM_DELETE_WINDOW", app.exit_func())
That code is functionally identical to this:
result = app.exit_func()
root.protocol("WM_DELETE_WINDOW", result)
Instead, you need to pass in a reference to the function:
root.protocol("WM_DELETE_WINDOW", app.exit_func)

Python tkinter trace error

I'm trying to write a GUI for my code. My plan is to use tkinter's StringVar, DoubleVar, etc. to monitor my input in real time. So I found out the DoubleVar.trace('w', callback) function. However, every time I make the change I get an exception:
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\Anaconda2\lib\lib-tk\Tkinter.py", line 1542, in __call__
return self.func(*args)
TypeError: 'NoneType' object is not callable
I have no idea what's going wrong. I'm using python 2.7
My code is as follows:
from Tkinter import *
class test(Frame):
def __init__(self,master):
Frame.__init__(self,master=None)
self.main_frame = Frame(master);
self.main_frame.pack()
self.testvar = DoubleVar()
self.slider_testvar = Scale(self.main_frame,variable = self.testvar,from_ = 0.2, to = 900, resolution = 0.1, orient=HORIZONTAL,length = 300)
self.slider_testvar.grid(row = 0, column = 0, columnspan = 5)
self.testvar.trace('w',self.testfun())
def testfun(self):
print(self.testvar.get())
root = Tk()
root.geometry("1024x768")
app = test(master = root)
root.mainloop()

Consider this line of code:
self.testvar.trace('w',self.testfun())
This is exactly the same as this:
result = self.testfun()
self.testvar.trace('w', result)
Since the function returns None, the trace is going to try to call None, and thus you get 'NoneType' object is not callable
The trace method requires a callable. That is, a reference to a function. You need to change that line to be the following (notice the missing () at the end):
self.testvar.trace('w',self.testfun)
Also, you need to modify testfun to take arguments that are automatically passed by the tracing mechanism. For more information see What are the arguments to Tkinter variable trace method callbacks?

root.after unable to find function_name

I am trying to put together a GUI that would read from a continuously updated TXT file and updated every once in a while. So far I succeeded with the first part and I am failing to use 'root.after()' to loop the whole thing but it results in NameError:
import tkinter as tk
root = tk.Tk()
class App:
def __init__(self, root):
frame = tk.Frame(root)
frame.pack()
iAutoInEN = 0
iAvailableEN = 0
self.tkAutoInEN = tk.StringVar()
self.tkAutoInEN.set(iAutoInEN)
self.tbAutoInEN = tk.Label(root, textvariable=self.tkAutoInEN)
self.tbAutoInEN.pack(side=tk.LEFT)
self.button = tk.Button(frame, text="Start", fg="red",
command=self.get_text)
self.button.pack(side=tk.LEFT)
def get_text(self):
fText = open("report.txt") #open a text file in the same folder
sContents = fText.read() #read the contents
fText.close()
# omitted working code that parses the text to lines and lines
# to items and marks them with numbers based on which they are
# allocated to a variable
if iLineCounter == 1 and iItemCounter == 3:
iAutoInEN = int(sItem)
self.tkAutoInEN.set(iAutoInEN)
root.after(1000,root,get_text(self))
app = App(root)
root.mainloop()
try:
root.destroy() # optional; see description below
except:
pass
The first instance runs without any problems and updates the value from 0 to the number in the TXT file but is accompanied with an error
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\...\Python35\lib\tkinter\__init__.py", line 1549, in __call__
return self.func(*args)
File "C:/.../pythonlab/GUI3.py", line 117, in get_text
self.after(1000,root,get_text())
NameError: name 'get_text' is not defined
EDIT:
When changed to the recommended "self.after(1000,self.get_text)"
class App:
...
def get_text(self):
fText = open("report.txt") #open a text file in the same folder
sContents = fText.read() #read the contents
fText.close()
# omitted code
if iLineCounter == 1 and iItemCounter == 3:
iAutoInEN = int(sItem)
self.tkAutoInEN.set(iAutoInEN)
self.after(1000,self.get_text)
Error changes
Traceback (most recent call last):
File "C:/.../pythonlab/GUI3.py", line 6, in <module>
class App:
File "C:/.../pythonlab/GUI3.py", line 117, in App
self.after(1000, self.get_text)
NameError: name 'self' is not defined
Also please consider this is my very first programme (not only) in Python, so I would appreciate if you are a little bit more explicit with your answers (e.g. when pointing out an indentation error, please refer to an exact line of code).

Because get_text is a method of App class you should call it as self.get_text.
After is a tkinter method. In that case you should call it as root.after. And self refers to the class you are in. So because get_text is a method of current class you should call is with self which is like this in other programming languages like Java.
...
root.after(1000, self.get_text)
...

Firstly, like James commented, you should fix your indentation so that the functions are a part of the class.
Then, change this line
root.after(1000,root,get_text(self))
to this
root.after(1000, self.get_text)
Check out the answer to the following question, which uses the code I just gave you:
Tkinter, executing functions over time

global name 'display' is not found

I'm currently designing a code for a troubleshooter. My problem is that when I press "other", there should be a data entry form label, which there is. But when i type something into it and press continue, it shows an error that says "
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python33\lib\tkinter\__init__.py", line 1482, in __call__
return self.func(*args)
File"R:\ICT\ControlledAssessment_15_17\Computing\Unit3\RiddhiSharma\FinalTroubleshooter.py", line 15, in click
display.insert(END, key)
NameError: global name 'display' is not defined
I think the problem in my actual code is here:
def click():
display.insert(END, key)
output.delete(0.0, END)
try:
entered_text=entry.get()
definition = my_glossary[entered_text]
except:
definition = "There is no entry for this word."
output.insert(END, definition)

Apparently display is not part of the tkinter module or it is not defined altogether. So when you try to use it, it raises an error because you have not defined display as a variable, function, class etc. So define display is a function that takes two arguments, END and key.
When defining display. You could do something like this:
display = 123
You could also make it a ENTRY, or whatever display is supposed to be. In your case, display doesn't have to be equal to 123. It could be equal to a class:
display = Display()
Just define Display() first... but display can be anything you want, as long you define it and use it correctly.

#PythonMaster thanks a lot for your help. To solve my problem I replaced the display function and wrote the code out like this:
def click():
entered_text = entry.get()
output.delete(0.0, END)
try:
definition = my_glossary[entered_text]
except:
definition = "There is no entry for this word."
output.insert(END, definition)