Update Labels in tkinter

Question

I am adding a "select file section" to my code. I would like to have two options, first choosing file path and second entering the file path.

Another feature I couldn't implement is that if the user choose the file path, that path appears in the entry section.

This is the section of the code that I am talking about:

from tkinter import filedialog
import tkinter as tk

class open_file:
    def __init__(self, master):
        self.master = master
        self.file_path = ''

        self.b1 = tk.Button(master,
               text = 'Open',
               command = self.open_file).grid(row=0, column=1)

        v = tk.StringVar(root, value = self.file_path)
        self.l1 = tk.Entry(master, width=24, textvariable=v).grid(row=0, column=0)


    def open_file(self):
        self.file_path = filedialog.askopenfilename(filetypes = (("Python Files", "*.py")
                                                             ,("All files", "*.*") ))

root = tk.Tk()
app = open_file(root)
root.mainloop()

Answer 1

Since you have a StringVar linked to the text, you'll need to use StringVar.set() in order to set the text of the entry.

From http://effbot.org/tkinterbook/variable.htm:

The set method updates the variable, and notifies all variable observers. You can either pass in a value of the right type, or a string.

You've set the contents on the StringVar, but they won't update dynamically whenever self.file_path changes. In your case you'll have to make the StringVar (v) a class member in the __init__ function

 self.v = tk.StringVar(root, value = self.file_path)

Additionally, when you want to update the file path set it via self.v.set(String)

def open_file(self):
        self.file_path = filedialog.askopenfilename(filetypes = (("Python Files", "*.py")
                                                            ,("All files", "*.*") ))
        if self.file_path:  #check if file path is not None or empty
                self.v.set(self.file_path)