How to terminate a tkinter loop and use a returned value

Question

I’ve setup a GUI to collect a file location. I then went to terminate the tkinter loop so I can use the submitted value to generate a file. With my current setup below the loop is not terminating.

I’ve had a few goes at moving around where root.mainloop() line is being called but not had any success.

from tkinter import *
from tkinter import filedialog

class InputForm:
    
    def __init__(self, master):
        
        # Cashflows 1 Input
        self.file_path1 = StringVar()
        Label(master, text="Input path 1:", fg='black', font=("Helvetica", 12)).place(x=10, y=10)
        self.file_path1 = Entry(master, text="Input path 1", bd=5, textvariable = self.file_path1)
        self.file_path1.place(x=120, y=10)
        Button(master, text = "Select", command = self.get_file_path1).place(x= 260, y = 10)

        master.title('Cashflow Summariser')
        master.geometry("310x160+10+20")
    
    #This needs to be simplified -> work out how to pass ByRef
    def get_file_path1(self):    
        self.file_path = filedialog.askopenfilename()
        self.file_path1.set(self.file_path)
    

    
    def submit(self):

        path1 = self.file_path1.get()

        paths = [path1]

        while("" in paths):
            paths.remove("")
        
        self.file_paths = paths

        self.master.destroy

class CashflowCombiner:
    def __init__(self, file_path):
        print(file_path)


        
def main():
    root = Tk()
    inputForm = InputForm(root)
    root.mainloop()

    file_paths = inputForm.file_paths

    print(file_paths)


if __name__ == '__main__': main()

Asked By: Rock1432

||

Source

Answer 1

You can terminate a tkinter loop by exiting the application either manually or by the user clicking the exit button.

You also have an issue with overwriting the self.file_path1 variable which will raise an exception when you try to set the value in the get_file_path1 method.

Here is an example of how you could do it.

from tkinter import *
from tkinter import filedialog

class InputForm:

    def __init__(self, master):
        self.master = master  # set master as an instance attribute
        self.file_path_var = StringVar()  # renamed this so it doesn't get overwritten
        Label(master, text="Input path 1:", fg='black', font=("Helvetica", 12)).place(x=10, y=10)
        self.file_path1 = Entry(master, text="Input path 1", bd=5, textvariable = self.file_path_var)
        self.file_path1.place(x=120, y=10)
        Button(master, text = "Select", command = self.get_file_path1).place(x= 260, y = 10)
        self.master.title('Cashflow Summariser')
        self.master.geometry("310x160+10+20")
        self.file_paths = []  # set the self.file_paths attribute to empty list

    #This needs to be simplified -> work out how to pass ByRef
    def get_file_path1(self):
        self.file_path = filedialog.askopenfilename()
        self.file_path_var.set(self.file_path)
        self.file_paths.append(self.file_path)  # append the path to self.file_paths
        #self.master.quit()  
        # uncommenting the above line will exit the mainloop after getting 
        # the file path from the user  or you can leave it commented and 
        # wait for the user to exit the window manually.


def main():
    root = Tk()
    inputForm = InputForm(root)
    root.mainloop()
    file_paths = inputForm.file_paths
    print(file_paths)

if __name__ == '__main__': main()

Most of the above seems rather unnecessary though… If all you want to do is use the file dialog, then you could probably just do something like this:

from tkinter import *
from tkinter import filedialog

def main():
    Tk()
    file_path = filedialog.askopenfilename()
    print(file_path)

if __name__ == '__main__': main()

Answered By: Alexander

How to terminate a tkinter loop and use a returned value

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