Python check if textbox is not filled

Question

Currently I'm using Python tkinter to build a GUI that require user to enter the detail into the textbox(txt3)

How do I validate if the textbox is entered. If not entered, should show message "please enter textbox" . If entered, it will go through SaveInDB() to save in database.

def SaveInDB():
    subID=(txt3.get())
    if not (subID is None):
        ...my code here to save to db
    else:
        res = "Please enter textbox"
        message.configure(text= res)`

txt3 = tk.Entry(window,width=20)
txt3.place(x=1100, y=200)

saveBtn = tk.Button(window, text="Save", command=SaveInDB ,width=20 )
saveBtn .place(x=900, y=300)

This code above does not work for me..Please help

Answer 1

You can check if the entry has any value and if not use showinfo to display a popup message. If you don't want a popup you can simply set the focus like entry.focus() or highlight the background with a different color. A minimal example of what you are trying to accomplish.

import tkinter as tk
from tkinter.messagebox import showinfo

def onclick():
    if entry.get().strip():
        print("Done")
    else:
        showinfo("Window", "Please enter data!")
        #or either of the two below
        #entry.configure(highlightbackground="red")
        #entry.focus()

root = tk.Tk()
entry = tk.Entry(root)
entry.pack()
tk.Button(root, text='Save', command=onclick).pack()
root.mainloop()

Pop up version

Focus version

Background color version