Composing widgets to display information

It is difficult to build large applications if all the code is contained in a single class. By splitting the GUI code into specific classes, we can modularize the structure of our program and create widgets with well-defined purposes.

Getting ready

Apart from importing the Tkinter package, we will import the Contact class from the preceding recipe:

import tkinter as tk
import tkinter.messagebox as mb

from chapter5_01 import Contact

Verify that the chapter5_01.py file is in the same directory; otherwise, this import-from statement will raise ImportError.

How to do it...

We will create a scrollable list that will show all contacts. To represent each item in the list as a string, we will display the contact's last and first names:

class ContactList(tk.Frame):
    def __init__(self, master, **kwargs):
        super().__init__(master)
        self.lb = tk.Listbox(self, **kwargs)
        scroll = tk.Scrollbar(self, command=self.lb.yview)

        self.lb.config...