Python3 Tkinter底部框架pack不显示问题求助（限用pack方法，无报错）

Alright, let's figure out why your bottom frame isn't showing up in Tkinter (using pack layout, no errors) — I've dealt with this exact quirk a few times before. Here are the most common causes and fixes tailored for Python 3.5:

1. You didn't pin the frame to the bottom with side=BOTTOM #

By default, pack() stacks widgets from top to bottom. If your top frame is set to fill the entire window, a bottom frame without side=BOTTOM will get pushed off the visible area of the window.

Fix: Explicitly set the bottom frame's pack side to bottom, and use fill=X to make it span the full width of the window:

from tkinter import *

root = Tk()
root.geometry("400x300")

# Top frame that takes up remaining space
top_frame = Frame(root, bg="red")
top_frame.pack(fill=BOTH, expand=True)

# Bottom frame fixed to the window's bottom
bottom_frame = Frame(root, bg="blue", height=50)
bottom_frame.pack(side=BOTTOM, fill=X)  # Critical: side=BOTTOM and fill=X

root.mainloop()

2. The bottom frame has no content or fixed dimensions #

Tkinter Frames shrink to the minimum size needed for their content. If your bottom frame is empty and you haven't set a height or width, it'll collapse to a 0x0 pixel box — invisible, even if it's correctly positioned.

Fix: Either add content to the frame, or set a fixed height/width:

# Option 1: Add content (e.g., a label)
bottom_frame = Frame(root, bg="blue")
bottom_frame.pack(side=BOTTOM, fill=X)
Label(bottom_frame, text="This is the bottom bar").pack(padx=10, pady=5)

# Option 2: Set a fixed height
bottom_frame = Frame(root, bg="blue", height=50)
bottom_frame.pack(side=BOTTOM, fill=X)
# Note: Use `pack_propagate(False)` if you don't want content to override the fixed size
bottom_frame.pack_propagate(False)

3. Your top frame is taking all available space without leaving room #

If your top frame uses fill=BOTH and expand=True without accounting for the bottom frame, it might stretch to fill the entire window, pushing the bottom frame out of view.

Fix: Ensure the bottom frame is packed before the top frame (pack order matters!), or keep using side=BOTTOM for the bottom frame (this takes priority regardless of pack order).

For example, packing bottom first works too:

bottom_frame.pack(side=BOTTOM, fill=X)
top_frame.pack(fill=BOTH, expand=True)

Quick Troubleshooting Tip #

Add a temporary background color to your bottom frame (like bg="yellow") — this makes it easier to see if it's actually present but just hidden or collapsed.

内容的提问来源于stack exchange，提问作者Fake