On 07/27/2016 03:12 AM, Peter Otten wrote:
Jim Byrnes wrote:
OOP has always driven me crazy. I read the material and follow the
examples until I feel I understand them, but when I try to implement it
I end up with an error filled mess.
So I decided to give it another try. When I got to the chapter on
tkinter I decided to solve all the exercises using OOP even though the
book solutions did not use OOP. The first one went fine:
No, it didn't. The Goodbye.quit() method is missing the self argument and
uses the inexistent self.window attribute.
You don't see these bugs when you run the script because there is a global
quit()... let's say function... that is called instead of the method.
You can put a print() into Goodbye.quit() to verify the above.
OK right. I ended up concentrating on exer2 when the problem was in
exer1. I should have known better than using quit() as a name.
#exer1.py
import tkinter
class Goodbye:
def __init__(self):
self.frame = tkinter.Frame(window)
self.frame.pack()
self.goodbye_button = tkinter.Button(self.frame, text='Goodbye',
#command=quit)
command=lambda: quit() )
The lambda is superfluous -- command=quit will already invoke the global
quit(). But what you actually intended is achieved with command=self.quit.
self.quit is called "bound method".
Ok, thanks.
self.goodbye_button.pack()
def quit():
print("you'll never see this")
self.window.destroy()
if __name__=='__main__':
window = tkinter.Tk()
myapp = Goodbye()
window.mainloop()
Regards, Jim
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