Python/Tkinter: why does the .get method of IntVar shows same value when clicking different radiobuttons?
Question: ## Brief overview of the program:

  1. When launching script, the dialog window is appearing and asking you to select directory path (class `MyApp`)
  2. When selected - one needs to push the "Start Monitoring" button. This action withdraws the main window (`root`) and initializes the container class `FrameContainer` consisting of two frames, namely `PageOne` and `PageTwo` (see corresponding classes). 
  3. Button `Back Home` on `Page One` should destroy the instance of the class `FrameContainer` and show the dialog window again. This action is achieved using methods `update()` and `deiconify()`.
  4. Selection of any of the radio buttons on `Page One` should change the value of variable `rb_indx` \- it is achieved using the `get()` method of `IntVar`. 

* * *

## Problems:

  * Radio buttons are initialized in wrong way. The `var.set(1)` should highlight the 'var1' button, however in my case are highlighted `var2` and `var3`.
  * The `get()` method of `IntVar` does not update the value of the variable `rb_indx` when selecting a radio button. `print rb_indx` always gives 1 
  * When closing `PageOne` window by the [x] (in corner of the screen), the dialog window is not appearing, however is expected... 

* * *

## The code:

    
    
    # -*- coding: utf-8 -*-
    
    try:
        # Python2
        import Tkinter as Tk
        from Tkinter import IntVar
        from tkFileDialog import askdirectory
    
    except ImportError:
        # Python3
        import tkinter as Tk
        from tkinter import IntVar
        from tkinter.filedialog import askdirectory
    
    LARGE_FONT=("Verdana", 12)
    
    ########################################################################
    
    class FrameContainer(Tk.Tk):
    
        def __init__(self, parent):
    
            self.original_frame = parent   
    
            Tk.Tk.__init__ (self)
            container = Tk.Frame(self)
    
            container.pack(side="top", fill="both", expand = True)
            container.grid_rowconfigure(0, weight=1)
            container.grid_columnconfigure(0, weight =1)
    
            self.frames = {}
    
            for F in (PageOne, PageTwo): 
    
                frame = F(container, self)
                self.frames[F] = frame
                frame.grid(row=0, column=0, sticky="nsew")
    
            self.show_frame(PageOne)
    
        def show_frame (self, cont):
    
            frame=self.frames[cont]
            frame.tkraise()
    
        def onClose(self):
    
            self.destroy()
            self.original_frame.show()  
    
    class PageOne(Tk.Frame):
    
        def __init__(self, parent, controller):
    
            Tk.Frame.__init__(self, parent)
    
            label = Tk.Label(self, text="Page One", font=LARGE_FONT)
            label.pack(pady=10, padx=10)
    
            button1=Tk.Button(self, text="Back to Home", command=lambda: controller.onClose())
            button1.pack()
    
            button2=Tk.Button(self, text="Page Two", command=lambda: controller.show_frame(PageTwo))
            button2.pack()
    
            def get_button_indx(): 
    
                global rb_indx
                rb_indx=var.get()
                print rb_indx
    
            var.set(1)
    
            names_tuple = ('var1', 'var2', 'var3')
    
            for col_numb in range (1,len(names_tuple)+1):
                radio = Tk.Radiobutton(self, text=names_tuple[col_numb-1], variable=var, value=col_numb, command=get_button_indx)
                radio.pack()
    
    class PageTwo(Tk.Frame):
    
        def __init__(self, parent, controller):
    
            Tk.Frame.__init__(self, parent)
    
            label = Tk.Label(self, text="Page Two", font=LARGE_FONT)
            label.pack(pady=10, padx=10)
    
            button1=Tk.Button(self, text="Back to Home", command=lambda: controller.onClose())
            button1.pack()
    
            button2=Tk.Button(self, text="Page One", command=lambda: controller.show_frame(PageOne))
            button2.pack()
    
    class MyApp(object):
    
        def __init__(self, parent):
    
            self.root = parent
            self.root.title("Start page")
            self.frame = Tk.Frame(parent)
            self.frame.pack()
    
            def choosedir():   
    
                global path_usr_var 
                path_usr_var = askdirectory()
                print path_usr_var
    
            button1 = Tk.Button(self.frame, text="Select Directory", command=choosedir)
            button1.pack(pady=10, padx=10)
    
            button2 = Tk.Button(self.frame, text="Start Monitoring", command=self.openFrame)
            button2.pack(pady=10, padx=10)
    
        def hide(self):
            self.root.withdraw()
    
        def openFrame(self):
            self.hide()
            firstFrame = FrameContainer(self)
    
        def show(self):
            self.root.update()
            self.root.deiconify()
    
    ########################################################################
    
    if __name__ == "__main__":
    
        root = Tk.Tk()
        root.geometry("800x600")
        var = IntVar()
        app = MyApp(root)
        root.mainloop()
    


Answer: The problem is that you're creating more than one instance of `Tk`. An app
must have exactly one instance of `Tk`.What is happening is that `var` belongs
to the first instance, but you are associating it with radio buttons that
belong to the second instance.

If you need multiple windows, create a single root window and then create
instances of `Toplevel` for all additional windows.

