How to display something after an Entry widget is filled in another area of the GUI?-CodePudding

I'm building a GUI to write to an excel spreadsheet. However, before I do the writing to spreadsheet, the user will input data in the GUI. What I want to do is when the user puts in a release number in the first entry and "tab" to the next entry, I want the date to automatically populate.

import tkinter
from tkinter import ttk
from tkinter import messagebox
import os
import openpyxl
from datetime import datetime


window = tkinter.Tk()
window.title("Truck Log Entry Form")

frame = tkinter.Frame(window)
frame.pack()

#saving truck logs
truck_info_frame = tkinter.LabelFrame(frame, text="Truck Information")
truck_info_frame.grid(row= 0, column=0, padx=20, pady=10)

release_number_label = tkinter.Label(truck_info_frame, text="Release Number")
release_number_label.grid(row=0,column=0)
truck_name_label = tkinter.Label(truck_info_frame, text="Truck Name")
truck_name_label.grid(row=0, column=1)
tare_info_label = tkinter.Label(truck_info_frame, text="Tare Weight")
tare_info_label.grid(row=0, column=2)
date_info_label = tkinter.Label(truck_info_frame, text="Date/Time")
date_info_label.grid(row=0, column=3)
gross_info_label = tkinter.Label(truck_info_frame, text = "Gross Weight")
gross_info_label.grid(row=0, column=4)


date_info_result_str = tkinter.StringVar()

release_number_entry = tkinter.Entry(truck_info_frame, textvariable=date_info_result_str)
truck_name_entry = tkinter.Entry(truck_info_frame)
tare_info_entry = tkinter.Entry(truck_info_frame)
#date_info_result = tkinter.Label(truck_info_frame, text='')
date_info_result = tkinter.Label(truck_info_frame)
date_info_result.grid(row=1, column=3)
date_info_result_str.trace('w', lambda *args: auto_date(release_number_entry.get()) )
release_number_entry.grid(row=1, column=0)
truck_name_entry.grid(row=1, column=1)
tare_info_entry.grid(row=1, column=2)


for widget in truck_info_frame.winfo_children():
    widget.grid_configure(padx=10, pady=5)

def auto_date(release_filled):

    print("in auto_date function "   release_filled)
    #release_filled = release_number_entry.get()

    if len(release_filled) >= 6:
        print("in len area")
        #datetime object containing current date and time
        now = datetime.now()

        #format date and time to dd/mm/YY H:M:S
        dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
        return dt_string
    else:
        print("made in error")
        #tkinter.messagebox.showwarning(title="Error", message="Please check release number")

window.mainloop()

I created a function for it to be called then tried to do a .trace method but that doesn't seem to work. Furthermore, I tried messing around with validate but it only returns true or false and I'm not sure how to get that and I suppose call another function to display the time under the data_info_label. I would appreciate any help on this.

Update (1/12/23): I was able to call on the function and get it to trace successfully but how do I return the date and time from the function into the label?

CodePudding user response：

What I want to do is when the user puts in a release number in the first entry and "tab" to the next entry, I want the date to automatically populate.

If you want to do something when the user presses the tab key, you can bind a function to the event <Tab>. You don't want to do it on a trace associated with a stringvar since that would be called every time the user inserts or deletes a single character.

Here's a very simple example showing one way to do it:

import tkinter as tk
from datetime import datetime

def insert_date(entry):
    now = datetime.now()
    label.configure(text=now.strftime("%c"))

root = tk.Tk()

entry = tk.Entry(root)
label = tk.Label(root)
entry.pack(side="top")
label.pack(side="top")

entry.bind("<Tab>", lambda event: insert_date(label))

root.mainloop()

When you run the above example and press the tab key while the first entry has keyboard focus, it will insert the date and time into the second entry.

CodePudding user response：

Thanks to @Brian Oakley, I was able to figure out the rest! Huge help and here's the code below to see how I did it.

import tkinter
from tkinter import ttk
from tkinter import messagebox
import os
import openpyxl
from datetime import datetime


window = tkinter.Tk()
window.title("Truck Log Entry Form")

frame = tkinter.Frame(window)
frame.pack()

#saving truck logs
truck_info_frame = tkinter.LabelFrame(frame, text="Truck Information")
truck_info_frame.grid(row= 0, column=0, padx=20, pady=10)

release_number_label = tkinter.Label(truck_info_frame, text="Release Number")
release_number_label.grid(row=0,column=0)
truck_name_label = tkinter.Label(truck_info_frame, text="Truck Name")
truck_name_label.grid(row=0, column=1)
tare_info_label = tkinter.Label(truck_info_frame, text="Tare Weight")
tare_info_label.grid(row=0, column=2)
date_info_label = tkinter.Label(truck_info_frame, text="Date/Time")
date_info_label.grid(row=0, column=3)
gross_info_label = tkinter.Label(truck_info_frame, text = "Gross Weight")
gross_info_label.grid(row=0, column=4)


#date_info_result_str = tkinter.StringVar()

#release_number_entry = tkinter.Entry(truck_info_frame, textvariable=date_info_result_str)
release_number_entry = tkinter.Entry(truck_info_frame)
truck_name_entry = tkinter.Entry(truck_info_frame)
tare_info_entry = tkinter.Entry(truck_info_frame)
#date_info_result = tkinter.Label(truck_info_frame, text='')
date_info_result = tkinter.Label(truck_info_frame)
date_info_result.grid(row=1, column=3)
#date_info_result_str.trace('w', lambda *args: auto_date(release_number_entry.get()) )
release_number_entry.grid(row=1, column=0)
truck_name_entry.grid(row=1, column=1)
tare_info_entry.grid(row=1, column=2)

release_number_entry.bind("<Tab>", lambda event: auto_date(release_number_entry.get()))


for widget in truck_info_frame.winfo_children():
    widget.grid_configure(padx=10, pady=5)

def auto_date(release_filled):

    print("in auto_date function "   release_filled)
    #release_filled = release_number_entry.get()

    if len(release_filled) >= 6:
        print("in len area")
        #datetime object containing current date and time
        now = datetime.now()

        #format date and time to dd/mm/YY H:M:S
        dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
        date_info_result.config(text = dt_string)
    else:
        print("made in error")
        #tkinter.messagebox.showwarning(title="Error", message="Please check release number")

window.mainloop()