Python Programming for the Absolute Beginner, 3rd Edition

Now that you've seen a nice variety of widgets used in isolation, it's time to combine them in one, larger GUI. I don't introduce any new concepts in the Mad Lib program, so I don't comment too much on the code.

Importing the Tkinter Module

As you probably know by now, you have to import the Tkinter module before you can use it:

# Mad Lib # Create a story based on user input # Michael Dawson 6/10/03 from Tkinter import *

The Application Class's Constructor Method

Like all other Application class constructors before it, this one initializes the newly created Application object and invokes its create_widgets() method:

class Application(Frame): """ GUI application that creates a story based on user input. """ def __init__(self, master): """ Initialize Frame. """ Frame.__init__(self, master) self.grid() self.create_widgets()

The Application Class's create_widgets() Method

This class creates all of the widgets in the GUI. The only new thing I do is create all three radio buttons in a loop, by moving through a list of strings for each radio button's text and value options:

def create_widgets(self): """ Create widgets to get story information and to display story. """ # create instruction label Label(self, text = "Enter information for a new story" ).grid(row = 0, column = 0, columnspan = 2, sticky = W) # create a label and text entry for the name of a person Label(self, text = "Person: " ).grid(row = 1, column = 0, sticky = W) self.person_ent = Entry(self) self.person_ent.grid(row = 1, column = 1, sticky = W) # create a label and text entry for a plural noun Label(self, text = "Plural Noun:" ).grid(row = 2, column = 0, sticky = W) self.noun_ent = Entry(self) self.noun_ent.grid(row = 2, column = 1, sticky = W) # create a label and text entry for a verb Label(self, text = "Verb:" ).grid(row = 3, column = 0, sticky = W) self.verb_ent = Entry(self) self.verb_ent.grid(row = 3, column = 1, sticky = W) # create a label for adjectives check buttons Label(self, text = "Adjective(s):" ).grid(row = 4, column = 0, sticky = W) # create itchy check button self.is_itchy = BooleanVar() Checkbutton(self, text = "itchy", variable = self.is_itchy ).grid(row = 4, column = 1, sticky = W) # create joyous check button self.is_joyous = BooleanVar() Checkbutton(self, text = "joyous", variable = self.is_joyous ).grid(row = 4, column = 2, sticky = W) # create electric check button self.is_electric = BooleanVar() Checkbutton(self, text = "electric", variable = self.is_electric ).grid(row = 4, column = 3, sticky = W) # create a label for body parts radio buttons Label(self, text = "Body Part:" ).grid(row = 5, column = 0, sticky = W) # create variable for single body part self.body_part = StringVar() # create body part radio buttons body_parts = ["bellybutton", "big toe", "medulla oblongata"] column = 1 for part in body_parts: Radiobutton(self, text = part, variable = self.body_part, value = part ).grid(row = 5, column = column, sticky = W) column += 1 # create a submit button Button(self, text = "Click for story", command = self.tell_story ).grid(row = 6, column = 0, sticky = W) self.story_txt = Text(self, width = 75, height = 10, wrap = WORD) self.story_txt.grid(row = 7, column = 0, columnspan = 4)

The Application Class's tell_story() Method

In this method, I get the values the user has entered and use them to create the one, long string for the story. Then, I delete any text in the text box and insert the new string to show the user the story he or she created.

def tell_story(self): """ Fill text box with new story based on user input. """ # get values from the GUI person = self.person_ent.get() noun = self.noun_ent.get() verb = self.verb_ent.get() adjectives = "" if self.is_itchy.get(): adjectives += "itchy, " if self.is_joyous.get(): adjectives += "joyous, " if self.is_electric.get(): adjectives += "electric, " body_part = self.body_part.get() # create the story story = "The famous explorer " story += person story += "had nearly given up a life-long quest to find The Lost City of " story += noun.title() story += "when one day, the " story += noun story += "found " story += person + ". " story += "A strong, " story += adjectives story += "peculiar feeling overwhelmed the explorer. " story += "After all this time, the quest was finally over. A tear came to " story += person + "'s " story += body_part + ". " story += "And then, the " story += noun story += "promptly devoured " story += person + ". " story += "The moral of the story? Be careful what you " story += verb story += "for." # display the story self.story_txt.delete(0.0, END) self.story_txt.insert(0.0, story)

The Main Part of the Program

You've seen this code more than a few times before. I create a root window and an Application instance. Then, I start the whole GUI up by invoking root's mainloop() method.

# main root = Tk() root.title("Mad Lib") app = Application(root) root.mainloop()