如何应对tkinter事件？

Question

I'm doing some work with GUI in python. I'm using the Tkinter library.

I need a button, which will open a .txt file and do this bit of processing:

frequencies = collections.defaultdict(int)    # <-----------------------
with open("test.txt") as f_in:                  
    for line in f_in:
        for char in line:
            frequencies[char] += 1
total = float(sum(frequencies.values()))      #<-------------------------

I started with:

from Tkinter import *               
import tkFileDialog,Tkconstants,collections

root = Tk()
root.title("TEST")
root.geometry("800x600")

button_opt = {'fill': Tkconstants.BOTH, 'padx': 66, 'pady': 5}
fileName = ''
def openFile():
    fileName = tkFileDialog.askopenfile(parent=root,title="Open .txt file", filetypes=[("txt file",".txt"),("All files",".*")])
Button(root, text = 'Open .txt file', fg = 'black', command= openFile).pack(**button_opt)



frequencies = collections.defaultdict(int)    # <-----------------------
with open("test.txt") as f_in:                  
    for line in f_in:
        for char in line:
            frequencies[char] += 1
total = float(sum(frequencies.values()))      #<-------------------------



root.mainloop()

Now I don't know how to assemble my code so it runs when the button is pressed.

Answer 1

The main problem was tkFileDialog.askopenfile() returns an open file rather than a file name. This following seemed to be more-or-less working for me:

from Tkinter import *
import tkFileDialog, Tkconstants,collections

root = Tk()
root.title("TEST")
root.geometry("800x600")

def openFile():
    f_in = tkFileDialog.askopenfile(
                            parent=root,
                            title="Open .txt file",
                            filetypes=[("txt file",".txt"),("All files",".*")])

    frequencies = collections.defaultdict(int)
    for line in f_in:
        for char in line:
            frequencies[char] += 1
    f_in.close()
    total = float(sum(frequencies.values()))
    print 'total:', total

button_opt = {'fill': Tkconstants.BOTH, 'padx': 66, 'pady': 5}
fileName = ''
Button(root, text = 'Open .txt file',
       fg = 'black',
       command= openFile).pack(**button_opt)

root.mainloop()

For quickly creating simple GUI programs I highly recommend EasyGUI , a fairly powerful yet simple Tk --based Python module for doing such things.

Answer 2

Try something laid out a bit like this:

class my_app():
    def __init__():
        self.hi_there = Tkinter.Button(frame, text="Hello", command=self.say_hi)
        self.hi_there.pack(side=Tkinter.LEFT)

    def say_hi():
        # do stuff

You also may want to read:

This tutorial on Tkinter,

And this one.

EDIT: The OP wanted an example with his code (I think) so here it is:

from Tkinter import *               
import tkFileDialog,Tkconstants,collections

class my_app:
    def __init__(self, master):
        frame = Tkinter.Frame(master)
        frame.pack()

        self.button_opt = {'fill': Tkconstants.BOTH, 'padx': 66, 'pady': 5}
        self.button = Button(frame, text = 'Open .txt file', fg = 'black', command= self.openFile).pack(**button_opt)

        self.calc_button = Button(frame, text = 'Calculate', fg = 'black', command= self.calculate).pack()

        self.fileName = ''

    def openFile():
        fileName = tkFileDialog.askopenfile(parent=root,title="Open .txt file", filetypes=[("txt file",".txt"),("All files",".*")])

    def calculate():
        ############################################### *See note
        frequencies = collections.defaultdict(int)    # <-----------------------
        with open("test.txt") as f_in:                  
            for line in f_in:
               for char in line:
                   frequencies[char] += 1
        total = float(sum(frequencies.values()))      #<-------------------------
        ################################################

root = Tk()

app = App(root)

root.title("TEST")
root.geometry("800x600")

root.mainloop()

*Note: Nowhere in your code did I see where collections came from so I wasn't quite sure what to do with that block. In this example I have set it to run on the

Answer 3

在您的openFile()函数中，在您询问用户文件名之后，放上您的代码！