Python中的Tkinter-条目小部件不显示

Question

I am trying to make an entry widget display beneath a Label using the .grid() function; however, it is simply not showing up. Here is my code:

#demonstrates how to use a class with Tkinter

from Tkinter import *
import tkMessageBox

class Application(Frame):

    def __init__(self, master):
        """ Initializes the Frame"""
        Frame.__init__(self, master)
        self.grid()
        self.create_widgets()

    def create_widgets(self):
        self.previous_trans = Text(width = 100, height = 5, wrap = WORD)
        self.previous_trans.grid(row = 0, column = 0, columnspan = 2)

        self.items = Text(width = 50, height = 16, wrap = WORD)
        self.items.grid(row = 1, column = 1, rowspan = 14, sticky = E)

        self.additem = Label(text = "Add Item")
        self.additem.grid(row = 1)

        self.myentry = Entry(self)
        self.myentry.grid(row = 2)

root = Tk();
root.title("Work In Progress")
app = Application(root)

root.mainloop();

Answer 1

The reason is because:

1. you don't specify a row or column for app , so it defaults to 0,0
2. you don't specify a parent for self.previous_trans so it defaults to the root window -- the same as for the application frame
3. you explicitly put self.previous_trans in row zero, column zero, which overwrites the label

You need to be giving an explicit parent of self to all of the widgets inside of Application :

    self.previous_trans = Text(self, ...)
    self.items = Text(self, ...)
    self.additem = Label(self, ...)
    self.myentry = Entry(self, ...)