无按钮填充进度条

Question

我正在尝试制作一个进度条，想让它在窗口打开时自动开始填充。
所以我没有做一个按钮来触发填充进度条的功能，而是直接调用这个填充的函数。结果让我意外的是，窗口一开始是空的，过了5秒（填充进度条的时间）后，进度条才显示为填满。
问题是，当我用按钮替换这个填充函数时，它就能正常工作。那么，为什么直接调用这个函数不行呢？我该如何让它在没有按钮的情况下也能填充呢？
我的代码：

from tkinter import *
from tkinter import ttk as ttk
from time import *

def fill():
    t = 100
    x = 0
    s = 1
    while x <= t:
        bar['value'] += s
        x += s
        sleep(0.05)
        window2.update_idletasks()


def read():

    global window2
    window2 = Tk()

    global bar
    bar = ttk.Progressbar(window2,orient=HORIZONTAL,length=300)
    bar.pack(pady=15)

    fill()       # here I replace the function with a button calling it and it works well but I don't want a button

    window2.mainloop()

read()

Answer 1

你的问题是因为在 tkinter 中使用了 time.sleep。

应该改用 after 调度器。

下面的代码修改和注释展示了一种实现方法。

from tkinter import *
from tkinter import ttk as ttk

def fill(s, c):
    c = c + 1
    # Update progressbar
    bar['value'] = c
    # Test for exit conditions
    if c <= s:
        # Repeat action recursively by passing current values back to itself
        window2.after(50, fill, s, c)
    else:
        bar.destroy()
        # Ready to continue creating other widgets

def read():

    global window2
    window2 = Tk()

    global bar

    delay, steps, count = 50, 100, 0

    # Include the maximum step value `steps` for given length
    bar = ttk.Progressbar(window2, orient = HORIZONTAL, length = 300, maximum = steps)
    bar.pack(pady=15)
    # Begin by using `after` scheduler with `delay` to pass `steps` and `count` to `fill` function
    window2.after(delay, fill, steps, count)

    window2.mainloop()

read()