无法使用tkinter创建Entry窗口小部件

Question

I'm having some trouble creating an entry widget with tkinter. I've imported the necessary modules and have already created several buttons and check boxes. However I cannot figure out how to properly initialize the Entry. Here is my relevant code:

# Necessary Modules.------------------------------------------------------------
import win32com.client as win32
import re
from tkinter import *
from tkinter.filedialog import askopenfilename
import tkinter.messagebox


# Class for selecting the file.-------------------------------------------------
class FilenameClass():
    def __init__(self):
        self.location = 'User Import.txt'

    def getFile(self, identity):
        self.file_opt = options = {}
        options['defaultextension'] = '.txt'
        options['filetypes'] = [('Text Document (.txt)', '.txt'),
                                ('all files', '.*')]
        self.filename = askopenfilename(**self.file_opt)
        if self.filename:
            if 'User Import' in identity:
                self.location = self.filename
                app.get_txt_File['bg'] = '#0d0'
                user_file = open(self.filename, 'r')
                user_total = user_file.read()
                remove_lines = user_total.splitlines()
                for user in remove_lines:
                    regex_tab = re.compile('\\t')
                    user_info = regex_tab.split(user)
                    app.users.append(user_info)
            else:
                app.loadButton['bg'] = '#e10'


# Main Class.-------------------------------------------------------------------
class Application(Frame, Tk):
    def __init__(self, master=None):
        Frame.__init__(self, master)
        self.users = []
        self.fileOBJtxt = FilenameClass()
        self.createWidgets()

    def createWidgets(self):

        # Define the default values for the options for the buttons
        # Grid layout options
        self.rowconfigure(0, minsize=5)
        self.width = 54
        self.grid(padx=5)
        self.loadButton_gopt = {'row':1,'column':1,'padx': 2, 'pady': 5}
        self.loadButton_wopt = {'width': round(self.width),'bg':'#e10'}
        self.loadButton()
        self.trainingCheckBox()
        self.signatureInput()

    def loadButton(self):
        '''Button that calls the filename class which allows the user to select
        the text file they wish to use.'''

        self.get_txt_File = Button(self, text="Load User List", \
        command=lambda: self.fileOBJtxt.getFile('User Import'))
        for key, value in self.loadButton_wopt.items():
            self.get_txt_File[key] = value
        self.get_txt_File.grid(**self.loadButton_gopt)

    def trainingCheckBox(self):

        self.training_var = IntVar()
        self.training = Checkbutton(text="Include training video?", \
        variable=self.training_var).grid(row=2, sticky=W)

    def signatureInput(self):

        Label(text="Signature Name").grid(row=4, sticky=W)
        entry = Entry(bg='#fff', width=50)
        entry.grid(row=4, column=1, columnspan=4)     

# Initialization parameters.----------------------------------------------------
if __name__ == '__main__':
    app = Application()
    app.master.title('User Notification Tool')
    app.master.geometry('405x550+100+100')
    app.master.resizable(width=False, height=False)
    app.mainloop()

I'm not seeing any tracebacks, but I can't seem to get my Entry box to show up. What am I doing wrong?

EDIT: added entire code.

Answer 1

The problem with your entry field is you have not told it what frame/window to be placed in.

Change:

entry = Entry(bg='#fff', width=50)

To:

entry = Entry(self, bg='#fff', width=50)

Make sure you always provide the window/frame that a widget is going to be placed in as the first argument. In this case it is self as self refers to a frame.

Keep in mind that your program will not be able to get() the string inside of your entry field because you have not defined it as a class attribute. So most likely you will need to change

This:

entry = Entry(bg='#fff', width=50)
entry.grid(row=4, column=1, columnspan=4)    

To This:

self.entry = Entry(self, bg='#fff', width=50)
self.entry.grid(row=4, column=1, columnspan=4)     

This change will be necessary in order for the rest of your application to be able to read or write to the entry widget.

Answer 2

Change

entry = Entry(bg='#fff', width=50)

to

entry = tk.Entry(bg='#fff', width=50)