Python PySimpleGUI：如何等待条件满足且不冻结GUI？

我正在学习用Python制作GUI，目标是用其操控实验室设备，目前遇到了让GUI等待条件满足的问题。

最初尝试使用如下while循环（实际代码中会定期向测量设备发送查询，例如判断是否完成测量）：

while i < some_limit:
    time.sleep(1)
    print(i) 
    i+=1

查阅资料后发现time.sleep()会导致GUI冻结，解决方法之一是使用线程，于是编写了如下示例代码：

import threading
import time
import PySimpleGUI as sg

def side_thread(limit):
    i=0
    while i<=limit:
        time.sleep(1)
        print(i)
        i+=1
    return 

layout = [
            [sg.Text('current state:'), sg.Text(key='-STATE_OUT-')],
            [sg.Text('limit'), sg.Input(key='-LIMIT-', s=5)],
            [sg.Button('start counting')]
        ]

window = sg.Window('thread and GUI testing',layout)

while True:
    event, values = window.read()
    
    if event == sg.WIN_CLOSED:
        break

    if event == 'start counting':
        timelimit = float(values['-LIMIT-'])
        
        window['-STATE_OUT-'].update('count starting')

        c_thread = threading.Thread(target=side_thread, kwargs={'limit': timelimit})
        c_thread.start()
        
        # if side thread has returned then continue
        
        c_thread.join()
        window['-STATE_OUT-'].update('count finished')

期望流程 #

• 点击“start counting”按钮；
• 显示文本“current state: count starting”；
• 程序开始计数至设定上限，且GUI不冻结；
• 显示文本“current state: count finished”。

但实际情况是点击按钮后GUI立即冻结（“count starting”不显示），直到循环结束才显示“count finished”。

之后尝试使用window.TKroot.after()：

window = sg.Window('thread and GUI testing',layout)

while True:
    event, values = window.read()
    
    if event == sg.WIN_CLOSED:
        break
    if event == 'start counting':
        timelimit = float(values['-LIMIT-'])
        window['-STATE_OUT-'].update('count starting')
        
        i=0
        while i<timelimit:
            window.TKroot.after(1000)
            print(i)
            i+=1
        
        window['-STATE_OUT-'].update('count finished')

但问题依旧。

后续疑问：能否在for循环中实现write_event_value？ #

示例代码如下：

import threading
import time
import PySimpleGUI as sg

layout = [
            [sg.Text('Counting Sequence')],
            [sg.Text('current progress'), sg.Text(key='-PR_OUT-')],
            [sg.Text('repeat count'), sg.Text(key='-RC_OUT-')],
            [sg.Text('set repeat count'), sg.Input(key='-Set_RC-', s=10)],
            [sg.Button('start sequence')]
        ]


def sequence_thread(limit):
    i=0
    while i<=limit:
        time.sleep(1)
        print(i)
        i+=1
    return

window = sg.Window('thread and GUI testing',layout)

while True:
    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break

    
    if event == 'start sequence':
        endpoint = int(values['-Set_RC-'])
        window['-PR_OUT-'].update('sequence starting')

        for i in range(endpoint):
            c_thread = threading.Thread(target=sequence_thread, args=(3,))
            c_thread.start()
            c_thread.join()
            rep_count = i+1
            window['-RC_OUT-'].update(str(rep_count))
        
        window['-PR_OUT-'].update('sequence finished')


window.close()

内容的提问来源于stack exchange，提问作者user1121