user interface - How to display a value from children window to parent window in python tkinter? -

i have parent window text , button. on clicking button in parent window child window opens contains entry box , button. when enter in entry box of child window , click submit of child window data entered in entry box of child window should appear in text box of parent window, how can this? code below.

from tkinter import *   class application(frame):      def __init__(self,  master):         super(application,self).__init__(master)         self.grid()         self.create_widgets()      def create_widgets(self):         self.t1=text(self,width=10,height=2)         self.t1.grid(row=1,column=1)         self.b1=button(self,text="create",command=self.onclick)         self.b1.grid(row=2,column=1)      def onclick(self):         self.top = toplevel()         self.top.title("title")         self.top.geometry("300x150+30+30")         self.top.transient(self)         self.appc=demo(self.top)  class demo:      def __init__(self, master):         self.master = master         self.frame = frame(self.master)         self.widget()      def widget(self):         self.e1=entry(self.master)         self.e1.grid(row=1,column=1)         self.b1=button(self.master,text="submit",command=self.onsubmit)         self.b1.grid(row=2,column=1)      def onsubmit(self):         self.value=self.e1.get()         print(self.value)     root=tk()     app=application(root)     app.mainloop()` 

you have pass reference of text widget child window via constructor. after have full control of widget in demo class. in onsubmit method use insert method:

from tkinter import * class application(frame, object):     def __init__(self,  master):         super(application, self).\             __init__(master)         self.grid()         self.create_widgets()       def create_widgets(self):         self.t1=text(self,width=10,height=2)         self.t1.grid(row=1,column=1)         self.b1=button(self,text="create",command=self.onclick)         self.b1.grid(row=2,column=1)      def onclick(self):         self.top = toplevel()         self.top.title("title")         self.top.geometry("300x150+30+30")         self.top.transient(self)         self.appc=demo(self.top, self.t1)  class demo(object):     def __init__(self, master, t1):         self.master = master         self.frame = frame(self.master)         self.t1 = t1         self.widget()      def widget(self):         self.e1=entry(self.master)         self.e1.grid(row=1,column=1)         self.b1=button(self.master,text="submit",command=self.onsubmit)         self.b1.grid(row=2,column=1)      def onsubmit(self):         self.t1.insert(insert, self.e1.get())   root=tk() app=application(root) app.mainloop()