Frame in canvas will not expand to fit canvas

问题

I am not sure why this will not work. I must be missing something because I can make a single frame expand to fit the canvas but I cannot make a frame inside a frame expand to fit the canvas.

I have been fighting with this for hours and I feel like its something obvious.

I am expecting the label inside of the NoteFrame to expand to fill the frame and that NoteFrame expand to fill the canvas.

Here is the minimum code to reproduce the behavior code:

import tkinter as tk


class NoteFrame(tk.Frame):
    def __init__(self, container):
        super().__init__(container)
        self.config(background='white')
        for i in range(20):
            tk.Label(self, text='test').grid(row=i, column=0, sticky='nsew')


class GCMain(tk.Tk):
    def __init__(self):
        super().__init__()
        self.columnconfigure(0, weight=1)
        self.rowconfigure(0, weight=1)

        self.main_canvas = tk.Canvas(self, background="bisque")
        self.main_canvas.columnconfigure(0, weight=1)
        self.main_canvas.rowconfigure(0, weight=1)
        self.frame_n_canvas = tk.Frame(self.main_canvas)
        self.frame_n_canvas.grid(row=0, column=0, sticky='nsew') # tried with and without this
        self.frame_n_canvas.columnconfigure(0, weight=1)
        self.main_canvas.config(scrollregion=self.main_canvas.bbox("all"), highlightthickness=0)
        scrollbar = tk.Scrollbar(self, orient='vertical')
        scrollbar.grid(row=0, column=1, sticky='nsw')
        scrollbar.config(command=self.main_canvas.yview)
        self.main_canvas.config(yscrollcommand=scrollbar.set)
        self.main_canvas.grid(row=0, column=0, sticky='nsew')
        self.main_canvas.create_window(0, 0, window=self.frame_n_canvas, anchor='nw')
        self.main_canvas.bind("<Configure>", self.update_scrollregion)

        nf = NoteFrame(self.frame_n_canvas)
        nf.grid(row=0, column=0, sticky='nsew') # tried with and without this

    def on_resize(self, event):
        w, h = event.width, event.height
        self.main_canvas.configure(width=w, height=h)
        self.frame_n_canvas(width=w, height=h) # tried with and without this

    def update_scrollregion(self, event):
        self.main_canvas.configure(scrollregion=self.main_canvas.bbox("all"))


if __name__ == '__main__':
    GCMain().mainloop()

回答1:

Comment: Dynamic solution

Allow your Label to be sticky='ew' use .grid_columnconfigure(0, weight=1).

class NoteFrame(tk.Frame):
    def __init__(self, container):
        super().__init__(container)
        self.grid_columnconfigure(0, weight=1)

You need the item iid of the Canvas(..., window= object.
No parameter width=200, height=200 are needed!

self.main_canvas.fram_n_canvas_iid =\
        self.main_canvas.create_window(0, 0, window=self.frame_n_canvas, anchor='nw')

Bind to "<Configure> as known.

self.main_canvas.bind("<Configure>", self.canvas_configure)

Resize .frame_n_canvas width in sync with .main_canvas width.

def canvas_configure(self, event):
    canvas = event.widget
    canvas.itemconfigure(canvas.fram_n_canvas_iid, width=canvas.winfo_width())

Question: Frame in canvas will not expand to fit canvas

A widget, here your Frame self.frame_n_canvas, looses the ability to expand, if placed with .create_window(... in a Canvas.

This, .grid(..., is useless, as you later place the same Frame with .create_window(...:

self.frame_n_canvas.grid(row=0, column=0, sticky='nsew') # tried with and without this
...
self.main_canvas.create_window(0, 0, window=self.frame_n_canvas, anchor='nw')

To give your NoteFrame place to expand, use parameter width=200, height=200.

self.main_canvas.create_window(0, 0, window=self.frame_n_canvas, anchor='nw',
                               width=200, height=200)

To allow your Label to be sticky='ew', you have to do .grid_columnconfigure(...:

class NoteFrame(tk.Frame):
    def __init__(self, container):
        super().__init__(container)
        self.grid_columnconfigure(0, weight=1)

Result:

来源：https://stackoverflow.com/questions/54794843/frame-in-canvas-will-not-expand-to-fit-canvas

标签

python

canvas

tkinter