按下按钮时 Ttk 不确定进度条

Question

我正在尝试创建一个运行的进度条，只要我的功能是运行向用户显示事情正在发生，而不仅仅是冻结。我的函数 (generate_reports) 查询数据库并写入 CSV 文件。这是我的代码的抽象版本：

from tkinter import *
from tkinter import ttk
from billing import generate_reports

class app:
  def __init__(self, root):
    self.mainframe = ttk.Frame(root, padding = '4 4 12 12')
    self.mainframe.grid(column = 0, row = 0, sticky = (N, W, E, S))
    ttk.Button(self.mainframe, text = "Generate Billing Reports", command = self.do_reports).grid(column = 2, row = 3, sticky = (W, E))
  
  def do_reports(self, *args):
     pbar = ttk.Progressbar(self.mainframe, orient = HORIZONTAL, mode = 'indeterminate')
     pbar.grid(row = 4, column = 3, sticky = (W, E))
     t1 = threading.Thread(target = generate_reports, args = [start, end])
     t1.start()
     pbar.start()
     t1.join()
     pbar.stop()
     return

root = Tk()
BillingApp(root)
root.mainloop()

使用这段代码，进度条直到generate_reports线程完成后才会弹出，并且是不动的。如果我删除连接，一切正常，但它永远不会停止加载。我怎样才能使加载栏运行仅在 generate_reports 线程的持续时间内？

Answer 1

嘿，欢迎来到事件驱动编程的有趣世界:)。您不能在这里使用 join，该函数的要点是阻塞直到线程完成，而使用线程的全部要点是避免阻塞主循环。您有 2 个选择：要么将 GUI 设置为不断轮询线程以查看它是否仍然运行，要么将线程设置为在完成时将消息发送回 GUI。后一个选项可能是最干净的，并且通常使用 tkinter 的事件机制来完成。

from tkinter import *
from tkinter import ttk
import threading
import time

def generate_reports(start, end):
    print("provide a mcve next time!")
    time.sleep(5)

def run_report(root, *args):
    generate_reports(*args)
    root.event_generate("<<PhishDoneEvent>>") # yes, this is using tkinter in a thread, but some tkinter methods are ok to use in threads

class BillingApp:
  def __init__(self, root):
    self.mainframe = ttk.Frame(root, padding = '4 4 12 12')
    self.mainframe.grid(column = 0, row = 0, sticky = (N, W, E, S))
    ttk.Button(self.mainframe, text = "Generate Billing Reports", command = self.do_reports).grid(column = 2, row = 3, sticky = (W, E))
    root.bind("<<PhishDoneEvent>>", self.report_done)

  def do_reports(self, *args):
    # note this makes a new widget with every click ... this is bad. Refactor to reuse the widget. 
    self.pbar = ttk.Progressbar(self.mainframe, orient = HORIZONTAL, mode = 'indeterminate')
    self.pbar.grid(row = 4, column = 3, sticky = (W, E))
    start, end = 4,5
    t1 = threading.Thread(target = run_report, args = [root, start, end])
    t1.start()
    self.pbar.start()

  def report_done(self, event=None):
    self.pbar.stop()
    Label(self.mainframe, text="report done").grid(row = 4, column = 3)

root = Tk()
BillingApp(root)
root.mainloop()

Answer 2

我看到你已经接受了上面的答案。但是，我会 post 我的答案，因为它不是基于线程的，我认为线程更简单，可能更合适：

from tkinter import *
from tkinter.ttk import *
import os



root = Tk()

# I set the length and maximum as shown to demonstrate the process in the 
# proceeding function
progress = Progressbar(root, orient = HORIZONTAL,
            length = 200/5, maximum=200/5, mode = 'determinate')

# Function 


def my_func():
    t=0
    r= 1/5   
    for i in range(200):
        print(i)
        t=t+r
        progress['value'] = t
        root.update_idletasks()
  

progress.pack()

# Button
Button(root, text = 'Start', command = bar).pack(pady = 10)


mainloop()

按下按钮时 Ttk 不确定进度条

Ttk Indeterminate progress bar on button press

python

tkinter

python-multithreading

ttk