Chapter 3. Hello, Again

Table of Contents
Running the Example
Details
More on widget references
More on widget names

When you write larger programs, it is usually a good idea to wrap your code up in one or more classes. The following example is adapted from the "hello world" program in Matt Conway's A Tkinter Life Preserver.

Example 3-1. Our Second Tkinter Program

# File: hello2.py

from Tkinter import *

class App:

    def __init__(self, master):

        frame = Frame(master)
        frame.pack()

        self.button = Button(frame, text="QUIT", fg="red", command=frame.quit)
        self.button.pack(side=LEFT)

        self.hi_there = Button(frame, text="Hello", command=self.say_hi)
        self.hi_there.pack(side=LEFT)

    def say_hi(self):
        print "hi there, everyone!"

root = Tk()

app = App(root)

root.mainloop()

Running the Example

When you run this example, the following window appears.

Figure 3-1. Running the sample program (using Tk 8.0 on a Windows 95 box)

If you click the right button, the text "hi there, everyone!" is printed to the console. If you click the left button, the program stops.

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