虽然我的示例代码不是最短的示例之一，但它是显示我的App内部工作的最小代码。
我的目标是要有一个保存弹出对话框，以更新进度条（在此示例中不是，不是问题）。 如果您尝试运行此代码，则将看到“保存”按钮-单击该按钮后，将弹出显示窗口。
但是我突然在 progress_bar（）方法中显示更新循环，突然不再显示弹出窗口-为什么？
我正在互联网上寻找解决方案。起初，我认为这与我在实际将文件保存到另一个线程时更新弹出窗口有关，但是此示例没有线程，并且注释了实际方法，因此问题必须在其他地方。
import kivy
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from time import sleep
# Main app with save method
class MainApp(App):
def build(self):
sm = ScreenManager()
self.save = save(app=self, name='save')
sm.add_widget(self.save)
self.saved_percent = 0.0
return sm
def save_file(self,file_path):
for i in range(0,10):
sleep(1)
self.saved_percent = i * 10.0
print("saved",i)
self.save_finnished = True
return 256 # check for written bytes
# one of many screens - this one is for saving
class save(Screen):
def __init__(self, app, **kwargs):
super(Screen,self).__init__(**kwargs)
self.app = app
lyo = BoxLayout(orientation='vertical')
btn = Button(text="Save", size=(10,10))
btn.bind(on_press=self.begin_save)
lyo.add_widget(btn)
self.add_widget(lyo) # basic layout to init the save
def begin_save(self,*args):
self.app.save_finnished = False
self.cancel_save = False
file_path = 'foo.txt' # debug static
self.progress_bar(file_path) # TODO put in separate thread and continue
#save_file(self,file_path)
def progress_bar(self, file_path):
btn = Button(text="Cancel")
btn.bind(on_press=self.btn_cancel_save)
pop = Popup(title="Saving", content=btn, auto_dismiss=False)
pop.open() # does not open
# this loop is somehow causing the Popup not to display
#while (not self.app.save_finnished and not self.cancel_save):
# pass # progres bar is being updated here
#pop.dismiss() # dismiss after exiting the loop
def btn_cancel_save(self, *args):
print("Cancel clicked")
self.cancel_save = True
if __name__ == "__main__":
top=MainApp()
top.run()
#
#import kivy
#from kivy.app import App
#from kivy.uix.screenmanager import ScreenManager, Screen
#from kivy.uix.boxlayout import BoxLayout
#from kivy.uix.progressbar import ProgressBar
#from kivy.uix.popup import Popup
#import threading
#from kivy.uix.label import Label
#from kivy.uix.button import Button
#from kivy.uix.boxlayout import BoxLayout
#from time import sleep
#from kivy.lang import Builder
#import queue
#
## Main app with save method
#class MainApp(App):
# def build(self):
# sm = ScreenManager()
# self.save = save(app=self, name='save')
# sm.add_widget(self.save)
# self.saved_percent = 0.0
# return sm
#
# def save_file(self,file_path):
# for i in range(0,10):
# sleep(1)
# self.saved_percent = i * 10.0
# print("saved",i)
# return 256 # check for written bytes
#
## one of many screens - this one is for saving
#class save(Screen):
# def __init__(self, app, **kwargs):
# super(Screen,self).__init__(**kwargs)
# self.app = app
# lyo = BoxLayout(orientation='vertical')
# btn = Button(text="Save", size=(10,10))
# btn.bind(on_press=self.begin_save)
# lyo.add_widget(btn)
# self.add_widget(lyo) # basic layout to init the save
#
# def begin_save(self,*args):
# self.save_finnished = False
# self.cancel_save = False
# file_path = 'foo.txt' # debug static
# #written = self.poi.save_file(file_path)
# #self.progress_bar(file_path)
#
# # some black magic with threads to get ret value
# # https://www.edureka.co/community/31966/how-to-get-the-return-value-from-a-thread-using-python
# #que = queue.Queue()
# #t = threading.Thread(target=lambda q, arg1: q.put(self.app.save_file(arg1)), args=(que, file_path))
# #t.start()
# self.progress_bar(file_path)
# #progress_bar_thread = threading.Thread(target=self.progress_bar, args=(file_path,))
# #progress_bar_thread.start()
# #t.join()
# #written = que.get()
#
## self.save_finnished = True
## size = os.path.getsize(file_path)
## if(not self.btn_cancel_save):
## if(written == size):
## print("OK")
## self.ok_dialog(True)
## else:
## print("Error saving to POI")
## self.ok_dialog(False)
#
# def progress_bar(self, file_path):
# print("progress bar fnc ")
# #lyo = BoxLayout(orientation='vertical')
# #pb = ProgressBar(max=100.0)
# #lbl = Label(text='0 %')
# btn = Button(text="Cancel")
# btn.bind(on_press=self.btn_cancel_save)
# #lyo.add_widget(Label(text=file_path))
# #lyo.add_widget(pb)
# #lyo.add_widget(lbl)
# #lyo.add_widget(btn)
#
# #pop = Popup(title="Saving", content=lyo, auto_dismiss=False)
# pop = Popup(title="Saving", content=btn, auto_dismiss=False)
# pop.open() # does not open
#
## print("start update loop")
## print("finished?",self.save_finnished, "cancel?" ,self.cancel_save)
# while (not self.save_finnished or not self.cancel_save):
# pass # progres bar is being updated here
## pb.value = self.app.saved_percent
## s = '%.12f' % self.app.saved_percent
## i, p, d = s.partition('.')
## str_percent = '.'.join([i, (d+'0'*2)[:2]])
## lbl.text = str_percent +' %'
## #print(" # ")
# print("out of update loop - dismiss pop")
# pop.dismiss()
#
# def ok_dialog(self,success):
# if(success):
# title = "SUCCESS"
# else:
# title = "FAILED"
# btn = Button(text="OK")
#
# pop = Popup(title=title, content=btn, auto_dismiss=False)
# btn.bind(on_press=pop.dismiss)
# pop.open()
#
#
# def btn_cancel_save(self, *args):
# print("Cancel clicked")
# self.cancel_save = True
#
#
#if __name__ == "__main__":
# top=MainApp()
# top.run()
答案 0 :(得分：1)
没有线程，它可能看起来像这样（但是如果迭代时间很长，它将非常无响应）
import time
from kivy.uix.progressbar import ProgressBar
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.popup import Popup
from kivy.uix.boxlayout import BoxLayout
from kivy.clock import Clock
class TestApp(App):
def build(self):
parent = Widget()
btn = Button(text='copy file', on_press=self.start_copy_file)
parent.add_widget(btn)
return parent
def start_copy_file(self, *args):
self.copy_cancel_flag = False
# open progressbar window
self.progress_bar = ProgressBar(max=50)
btn = Button(text="Cancel")
btn.bind(on_press=self.copy_cancel)
layout = BoxLayout()
layout.add_widget(self.progress_bar)
layout.add_widget(btn)
self.pop = Popup(title="Saving", content=layout)
self.pop.open()
self.copy_context_i = 0
Clock.schedule_once(self.copy_file_func, 1)
def copy_cancel(self, *args):
self.copy_cancel_flag = True
self.pop.dismiss()
def copy_file_func(self, dt):
print('thread_copy_file_func i =', self.copy_context_i)
self.progress_bar.value = self.copy_context_i
time.sleep(0.1)
if self.copy_cancel_flag:
pass # cancel condition
elif self.copy_context_i > 50:
pass # normal operation end
else:
self.copy_context_i += 1
Clock.schedule_once(self.copy_file_func) # run again
return # exit befor closing popup and cleanup
# end, close popup
# ... other cleanup ...
self.pop.dismiss()
TestApp().run()
答案 1 :(得分：0)
对于线程，我会使用类似的东西； 您必须退出按钮回调，否则eventloop不会重绘窗口小部件。
import time
from threading import Thread
from kivy.uix.progressbar import ProgressBar
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.popup import Popup
from kivy.uix.boxlayout import BoxLayout
class TestApp(App):
def build(self):
self.thread = None
parent = Widget()
btn = Button(text='copy file', on_press=self.start_thread_copy_file)
parent.add_widget(btn)
return parent
def start_thread_copy_file(self, *args):
if self.thread is None:
# open progressbar window
self.progress_bar = ProgressBar(max=5)
btn = Button(text="Cancel")
btn.bind(on_press=self.thread_copy_cancel)
layout = BoxLayout()
layout.add_widget(self.progress_bar)
layout.add_widget(btn)
self.pop = Popup(title="Saving", content=layout)
self.pop.open()
self.thread = Thread(target=self.thread_copy_file_func)
self.thread.start()
def thread_copy_cancel(self, *args):
self.thread = None # can be also done with a flag
self.pop.dismiss()
def thread_copy_file_func(self):
try:
for i in range(5):
print('thread_copy_file_func i =', i)
self.progress_bar.value = i
time.sleep(1)
if self.thread is None: # cancel condition
break
finally:
self.thread = None
self.pop.dismiss()
TestApp().run()