Python 2.7.2全局变量&x2B;特金特
我对全局变量有一些问题:Python 2.7.2全局变量&x2B;特金特,python,tkinter,global-variables,python-2.7,Python,Tkinter,Global Variables,Python 2.7,我对全局变量有一些问题: #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.Entr
#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()
当我点击按钮self.buttn=tk.button(master,text=“Done”,width=10,command=self.calc())时,我发现了这个问题。我想让self.result=tk.Label(self.master,text=globvar)
显示取自calc的globvar,但它显示在类globvar=0
之前设置的globvar。
我做错了什么
textvariable=self.globvar
,其中
self.globvar=tk.StringVar()
。通过调用self.globvar.set
更新标签文本command=self.calc()
更改为command=self.calc
(不带
括号)。使用括号时,将调用self.calc()
self.buttn
已定义。和命令设置为的返回值
self.calc()
,它是None
。按下按钮时不会发生任何事情
按下是因为命令
等于无
。没有括号,
命令
设置为函数对象self.calc
,并且
每当按下按钮时(正确地)调用函数Shuffle
实现自包含、更易于重用和导入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()