python - Tkinter Canvas create_window()

Question

I'm trying to use Tkinter Canvas (self._canvas) to create window using create_window function. The window field for that function is a Tkinter Frame (self._tableFrame). Can someone please help me out on how to make self._tableFrame to expand to size of self._canvas automatically (Even after the window size changed by user)?

Code:

from Tkinter import Scrollbar as tkScrollBar
from Tkinter import Frame as tkFrame
from Tkinter import Canvas as tkCanvas
from Tkinter import Entry as tkEntry
from Tkinter import StringVar as tkStringVar
from Tkinter import Tk, HORIZONTAL, N, S, E, W, RIGHT, LEFT, BOTTOM, X, Y, BOTH
from Tkinter import TOP


class Widget(tkFrame):
    def __init__(self, master=None):
        tkFrame.__init__(self, master)

        self._str    = tkStringVar()
        self._widget = tkEntry(self)

        self._widget.config(textvariable=self._str, borderwidth=1, width=0)
        self._widget.pack(expand=True, fill=X)

    def settext(self, str_):
        self._str.set(str_)

    def gettext(self):
        return self._str.get()


class Application(tkFrame):
    def __init__(self, rows, cols, master=None):
        tkFrame.__init__(self, master)

        yScroll = tkScrollBar(self)
        xScroll = tkScrollBar(self, orient=HORIZONTAL)

        self._canvas = tkCanvas(self,
                yscrollcommand=yScroll.set, xscrollcommand=xScroll.set)
        yScroll.config(command=self._canvas.yview)
        xScroll.config(command=self._canvas.xview)

        self._table      = [[0 for x in range(rows)] for x in range(cols)]
        self._tableFrame = tkFrame(self._canvas)

        for col in range(cols):
            self._tableFrame.grid_columnconfigure(col, weight=1)
            for row in range(rows):
                self._table[row][col] = Widget(master=self._tableFrame)
                self._table[row][col].settext("(%d, %d)" % (row, col))
                self._table[row][col].grid(row=row, column=col, sticky=E+W)

        # For debugging
        self._canvas.config(background="blue")
        self._tableFrame.config(background="red")

        yScroll.pack(side=RIGHT, fill=Y)
        xScroll.pack(side=BOTTOM, fill=X)

        self._canvas.create_window(0, 0, window=self._tableFrame, anchor=N+W)
        self._canvas.pack(side=LEFT, fill=BOTH, expand=True)


tkRoot  = Tk()

# Application Size and Center the Application
appSize = (800, 600)
w       = tkRoot.winfo_screenwidth()
h       = tkRoot.winfo_screenheight()

x = w / 2 - appSize[0] / 2
y = h / 2 - appSize[1] / 2
tkRoot.geometry("%dx%d+%d+%d" % (appSize + (x, y)))
tkRoot.update_idletasks() # Force geometry update

app = Application(5, 5, master=tkRoot)
app.pack(side=TOP, fill=BOTH, expand=True)
tkRoot.mainloop()

Answer 1

You can bind self._canvas with the event <Configure>, and then call itemconfig with the id of the frame added to the canvas (not directly the reference to the widget):

def __init__(self, rows, cols, master=None):
    # ...
    self._frame_id = self._canvas.create_window(0, 0, window=self._tableFrame, anchor=N+W)
    self._canvas.pack(side=LEFT, fill=BOTH, expand=True)
    self._canvas.bind("<Configure>", self.resize_frame)

def resize_frame(self, e):
    self._canvas.itemconfig(self._frame_id, height=e.height, width=e.width)

By the way, I recommend you to rewrite your import statements, which in my opinion are quite repetitive and unpythonic:

import Tkinter as tk
# Use tk.Tk, tk.Canvas, etc.