I'm having some problems with the global variables:
#Dev by Mkee
import Tkinter as tk
import sys, random
globvar = 0
class Shuffle(object):
def __init__(self,master=None):
self.master=master
self.text=tk.Label(master, text="Type in something:")
self.box=tk.Entry(master)
self.buttn = tk.Button(master, text="Done", width=10, command=self.calc())
self.result = tk.Label(self.master, text=globvar)
def hide(self):
self.text.pack_forget()
self.box.pack_forget()
self.buttn.pack_forget()
self.result.pack_forget()
def show(self):
self.text.pack(padx=2, pady=2)
self.box.focus_set()
self.box.pack(side=tk.TOP, padx=3, pady=3)
self.buttn.pack(side=tk.TOP, padx=3, pady=3)
self.result.pack(side=tk.TOP, padx=3, pady=3)
def calc(self):
word = self.box.get()
while len(word) != 0:
i = random.randrange(0, len(word))
global globvar
globvar = word[i]
word = word[0:i] + word[i+1:]
class MainApp(object):
def __init__(self,master=None):
self.master=master
app=self.app=tk.Tk()
app.title("Mkee's Tools")
app.geometry('500x500')
menubar=tk.Menu(app)
self.shuffle=Shuffle(master)
self.current=self.shuffle
program_menu=tk.Menu(menubar)
program_menu.add_command(label='Shuffle',command=self.show_shuffle)
menubar.add_cascade(label='Programs', menu=program_menu)
app.config(menu=menubar)
def show_shuffle(self):
self.current.hide()
self.current=self.shuffle
self.shuffle.show()
def show_buttons(self):
self.current.hide()
self.current=self.buttons
self.buttons.show()
def main():
m=MainApp()
m.app.mainloop()
if __name__=='__main__':
main()
I get the problem when I click the button self.buttn = tk.Button(master, text="Done", width=10, command=self.calc())
. I want to make the self.result = tk.Label(self.master, text=globvar)
show the globvar taken from calc, but instead it shows the globvar that is set before the class globvar = 0
. What am I doing wrong?
textvariable=self.globvar
, where self.globvar = tk.StringVar()
. The Label text is updated by calling self.globvar.set
. command=self.calc()
to command=self.calc
(without parentheses). With parentheses, self.calc()
is called at the time self.buttn
is defined. And command gets set to the return value of self.calc()
, which is None
. Nothing happens when the button is pressed because command
equals None
. Without parentheses, command
is set to the function object self.calc
, and the function is called (correctly) whenever the button is pressed. Shuffle
to be self-contained, more easily reusable and importable. import Tkinter as tk
import sys, random
class Shuffle(object):
def __init__(self,master=None):
self.master=master
self.text=tk.Label(master, text="Type in something:")
self.box=tk.Entry(master)
self.buttn = tk.Button(master, text="Done", width=10, command=self.calc)
self.globvar = tk.StringVar()
self.globvar.set(0)
self.result = tk.Label(self.master, textvariable=self.globvar)
def hide(self):
self.text.pack_forget()
self.box.pack_forget()
self.buttn.pack_forget()
self.result.pack_forget()
def show(self):
self.text.pack(padx=2, pady=2)
self.box.focus_set()
self.box.pack(side=tk.TOP, padx=3, pady=3)
self.buttn.pack(side=tk.TOP, padx=3, pady=3)
self.result.pack(side=tk.TOP, padx=3, pady=3)
def calc(self):
word = self.box.get()
while len(word) != 0:
i = random.randrange(0, len(word))
self.globvar.set(word[i])
word = word[0:i] + word[i+1:]
class MainApp(object):
def __init__(self,master=None):
self.master=master
app=self.app=tk.Tk()
app.title("Mkee's Tools")
app.geometry('500x500')
menubar=tk.Menu(app)
self.shuffle=Shuffle(master)
self.current=self.shuffle
program_menu=tk.Menu(menubar)
program_menu.add_command(label='Shuffle',command=self.show_shuffle)
menubar.add_cascade(label='Programs', menu=program_menu)
app.config(menu=menubar)
def show_shuffle(self):
self.current.hide()
self.current=self.shuffle
self.shuffle.show()
def show_buttons(self):
self.current.hide()
self.current=self.buttons
self.buttons.show()
def main():
m=MainApp()
m.app.mainloop()
if __name__=='__main__':
main()
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.