Python \\ Tkinter：使用存储在类之外的类函数中的变量

Question

I'm trying to make a GUI version of my program. This is the first time I use a GUI manager, specifically Tkinter. Basically the user insert a text (url) in an Entry widget, click a button and then the program does things. Consider the following code:

import Tkinter as tk
import urllib2

class Application(tk.Frame): 
    def __init__(self, master=None):
        tk.Frame.__init__(self, master) 
        self.grid() 
        self.createWidgets()
    def createWidgets(self):
        self.EntryText = tk.Entry(self, bg='red') 
        self.GetButton = tk.Button(self, text='Print',
                                command=self.GetURL) 
        self.GetButton.grid(row=0, column=1)
        self.EntryText.grid(row=0, column=0)

    def GetURL(self):
         url_target = ("http://www." + self.EntryText.get())
         req = urllib2.urlopen(url_target)
         print req.getcode()


app = Application() 
app.master.title('App') 
app.mainloop()

when I enter a valid url and click the button, I can get the text inserted and create the real url to pass to urllib2. However, how can I use the variable "req" anywhere in my program outside the function and the class?

Answer 1

Store the variable in the Application object:

def GetURL(self):
  url_target = ("http://www." + self.EntryText.get())
  self.req = urllib2.urlopen(url_target)

So you can use it in other methods of the class, for example

def do_something_with_req(self):
  print self.req.getcode()

How the method do_something_with_req is invoked is up to you (perhaps via another event listener callback).

Answer 2

Use a global variable (or if you want persistent storage the pickle or shelve modules):

""" main.py """

import Tkinter as tk
import urllib2
from testreq import fromTestreq, fromTestreq2

reqtext = ""                # Declaration of global variable

class Application(tk.Frame): 
    def __init__(self, master=None):
        tk.Frame.__init__(self, master) 
        self.grid() 
        self.createWidgets()
    def createWidgets(self):
        self.EntryText = tk.Entry(self, bg='red')
        self.EntryText.insert(0,"google.com")
        self.GetButton = tk.Button(self, text='Print', command=self.GetURLApp) 
        self.GetButton.grid(row=0, column=1)
        self.EntryText.grid(row=0, column=0)

    def GetURLApp(self):
        global reqtext       # Declaration of local variable as the global one
        url_target = "http://www." + self.EntryText.get()
        req = urllib2.urlopen(url_target)
        print req.geturl()
        print req.getcode()
        reqUrlStr = str(req.geturl())
        reqCodeStr = str(req.getcode())
        reqtext = reqUrlStr
        #reqtext = reqCodeStr
        fromTestreq(reqtext)
        #print reqtext


if __name__ == '__main__':
    app = Application() 
    app.master.title('App') 
    app.mainloop()
    fromTestreq2(reqtext)


""" testreq.py """

def fromTestreq(text):
    print("From testreq: " + text)

def fromTestreq2(text):
    print("From testreq2: " + text)