Open kivy popup before continuing

问题

My kivy popup does not appear on the screen until the rest of the code in my method finishes running. I am trying to display a progress bar so it is worthless in it's current state.

I have tried to thread the process to open the popup and tried without threading.

from kivy.uix.progressbar import ProgressBar
from kivy.uix.popup import Popup
import threading

def submit():
    popup = Popup(title='Submit Progress', content=ProgressBar())
    thread_object = threading.Thread(target=popup.open)
    thread_object.start()
    perform some iterable actions 
       increment progress bar value

    if progress_bar.value == progress_bar.max:
        popup.auto_dismiss = True
        # This is when the popup finally appears

I need the open function of my popup to actually take effect before performing the iterable actions so the user can watch the progress

回答1:

This is based on member 'inclement's' answer. I am not 100% what you are attempting to do but here is some code I tested that kicks off a long-running task in its own thread and holds the popup open until that task completes.

Kivy .kv file entry

Button:
    text: "do..."
    on_release: app.root.info_popup(self)  # your app may need root.info_popup(self)

In the app, the target method

def info_popup(self, _button: Button):
    print(str(type(_button)))
    popup_content = ProgressBar(max=10)

    popup = Popup(title="Countdown",
                  size_hint=(None, None), size=(400, 180),
                  content=popup_content,
                  auto_dismiss=False)
    print("starting a new thread to do the countdown")
    threading.Thread(target=partial(self.update_progress, an_object=popup_content,
                                    the_popup=popup), daemon=True).start()
    popup.open()

which starts this function as its own thread

def update_progress(self, an_object, the_popup: Popup):
    for i in range(10, -1, -1):
        time.sleep(1.0)
        print("progress: {}".format(i))
        an_object.value = i
    the_popup.dismiss()
    print("I have dismissed the popup")

回答2:

I solved the issue by using the Clock.schedule_once() function to schedule my other threaded updates.

来源：https://stackoverflow.com/questions/57732400/open-kivy-popup-before-continuing