not getting radiobutton 'value' from other function(def) in tkinter, how to achieve this without using class?

Question

Not getting radiobutton 'value' from other function(def) in tkinter, how to achieve this without using class?

In this case a=a1.get() is not taking value from command (of sub1 button) in ques1() function.

from tkinter import *

global root
root=Tk()
root.geometry("500x500")
a1=StringVar()
ans1=StringVar()

def ans1():
    a=a1.get()  #not getting it from ques1()
    print(a)

def ques1():
    root.destroy()
    global window1
    window1=Tk()
    window1.geometry("500x500")
    question1=Label(window1, text="How many Planets are there in Solar System").grid()
    q1r1=Radiobutton(window1, text='op 1', variable=a1, value="correct").grid()
    q1r2=Radiobutton(window1, text='op 2', variable=a1, value="incorrect").grid()
    sub1=Button(window1, text="Submit", command=ans1).grid()
    next1But=Button(window1, text="Next Question", command=ques2).grid()

def ques2():
    window1.destroy()
    window2=Tk()
    window2.geometry("500x500")
    question2=Label(window2, text="How many Planets are there in Solar System").grid()
    next2But=Button(window2, text="Next Question")


button=Button(root,text="Start Test", command=ques1).grid()

Answer 1

This is a side effect from using Tk more than once in a program. Basically, "a1" is tied to the "root" window, and when you destroy "root", "a1" will no longer work.

You have a couple options:

1. Keep the same window open all the time, and swap out the Frames instead.
2. Use Toplevel() to make new windows instead of Tk .

Option 1 seems the best for you. Here it is:

from tkinter import *

root=Tk()
root.geometry("500x500")
a1=StringVar(value='hippidy')
ans1=StringVar()

def ans1():
    a=a1.get()  #not getting it from ques1()
    print(repr(a))

def ques1():
    global frame
    frame.destroy() # destroy old frame
    frame = Frame(root) # make a new frame
    frame.pack()

    question1=Label(frame, text="How many Planets are there in Solar System").grid()
    q1r1=Radiobutton(frame, text='op 1', variable=a1, value="correct").grid()
    q1r2=Radiobutton(frame, text='op 2', variable=a1, value="incorrect").grid()
    sub1=Button(frame, text="Submit", command=ans1).grid()
    next1But=Button(frame, text="Next Question", command=ques2).grid()

def ques2():
    global frame
    frame.destroy() # destroy old frame
    frame = Frame(root) # make a new frame
    frame.pack()

    question2=Label(frame, text="How many Planets are there in Solar System").grid()
    next2But=Button(frame, text="Next Question")

frame = Frame(root) # make a new frame
frame.pack()
button=Button(frame,text="Start Test", command=ques1).grid()

root.mainloop()

Also, don't be scared of classes. They are great.

Also, the way you have a widget initialization and layout on the same line is known to cause bugs. Use 2 lines always. So instead of this

button=Button(frame,text="Start Test", command=ques1).grid()

Use this:

button=Button(frame,text="Start Test", command=ques1)
button.grid()

Answer 2

You need to use a single instance of Tk . Variables and widgets created in one cannot be accessed from another.

Answer 3

Your code has some common mistakes. You are creating a new window on each question. It is not a good idea. You can use Toplevel but I will suggest you to use the root . You can destroy all of your previous widgets and place new ones. When the first question, both radiobuttons are unchecked and return 0 when none is selected. You are creating the buttons in Window1 so you will have to tie it with your var.

from tkinter import *
global root
root=Tk()
root.geometry("500x500")
a1=StringVar(root)
a1.set(0)  #unchecking all radiobuttons
ans1=StringVar()

def ans1():
    a=a1.get()
    print(a)

def ques1():
    for widget in root.winfo_children():
        widget.destroy() #destroying all widgets
    question1=Label(root, text="How many Planets are there in Solar System").grid()
    q1r1=Radiobutton(root, text='op 1', variable=a1, value="correct").grid()
    q1r2=Radiobutton(root, text='op 2', variable=a1, value="incorrect").grid()
    sub1=Button(root, text="Submit", command=ans1).grid()
    next1But=Button(root, text="Next Question", command=ques2).grid()
def ques2():
    for widget in root.winfo_children():
        widget.destroy()
    question2=Label(root, text="How many Planets are there in Solar System").grid()
    next2But=Button(root, text="Next Question")


button=Button(root,text="Start Test", command=ques1)
button.grid()