Despite I am using Thread class in my long-term function, my GUI is freezing in PyQt5 and I couldn't solve the problem.
I am using separate py files in this process.
welding.py
`
python
from threading import Threading
class Weld:
def __init__(self):
self.power_supply = PowerSupply()
self.ui_object = ui_object
# Some code
run_cycle_threader = Thread(target = self.power_supply_run_cycle,
args = (self.ui_object,..some args..,self.simulation_mode,))
run_cycle_threader.start()
#some code
`
And at the other module like following:
power_supply.py
class PowerSupply:
def run_cycle(ui, someargs...,simulation_mode):
#some code interacting with physical device
#some code which changes GUI elements like Labels, ProgressBars and button colors
At other Threading objects I don't face with a problem but this function freezing GUI (for example prevents hovering of buttons)
I have tried to use QTimer class but I got same result.
My complete code is here:
https://github.com/emreisler/weld-redesign
Related
I am developing a QGIS Plugins, complex plugin with various classes and methods that call other methods.
My plugin works fine, but I'm loking to run some class method in the background (something like jobs in JAVA) to avoid frozen GUI. I mean, I have a class, this class has a method and this method I would like run in background
I tried with QThread,QTask, threading, QProcess, etc, but I did not find what I want to do.
Some idea could help me? Some plugin does works with background process? Some plugin example?
Thanks
I have been using QTask in order to run heavy processes in the background.
The useful ressources I am using are these ones :
https://gis.stackexchange.com/questions/94477/how-to-use-threads-in-pyqgis-mainly-to-keep-ui-active
https://github.com/qgis/QGIS/pull/3004
You have to specifically create a new Class that inherits from QgsTask and call it in the run() method of your GUI Plugin.
In my case this is what I have :
class MyPlugin:
"""QGIS Plugin Implementation.
... __init__ method, tr method, initGui method, ...
"""
def run(self):
"""Run method that performs the work after clicking 'OK' in the Plugin GUI"""
task = MyTask('UserFriendlyTaskName', **props)
QgsApplication.taskManager().addTask( task )
class MyTask(QgsTask):
def __init__(self, task_name, **props):
QgsTask.__init__(self, desc)
# do w/e with the props
def run(self):
# call your heavy processes
See this .gif below for the UI rendering in QGIS3, there is no freezing and I can still move on the map and edit data while the plugin is running.
QGIS GUI Launch Background Process GIF
Hope this answer finds you in time !
If i understand correctly, you want to refresh the UI to avoid QGIS freezing.
This is what worked for me:
from PyQt5.QtWidgets import QApplication
QApplication.processEvents()
This will refresh the UI of QGIS.
You probably have to call it multiple time, for example after every iteration in a for loop.
thanks you for your answer
what I would to do is run a method in background without freezing QGIS GUI
a example of my code
class Example:
def __init__(self):
code
self.createBotton()
def createButton(self):
Here I create my button
self.okbutton.clicked.connect(self.pressOkButton)
def pressOkButton(self):
here I call other methods
self.methodA()
self.methodB()
def methodA(self):
code
def methodB(self):
code
my question is--> how can i run 'pressOkButton' method in background? When i executed this method i can not ineract with QGIS GUI until finish method
NOTE:consider that it is a class that belongs to my plugin so this class is instantiated when starting the plugin
How can I architect code to run a pyqt GUI multiple times consecutively in a process?
(pyqtgraph specifically, if that is relevant)
The context
A python script that performs long running data capture on measurement equipment (a big for loop). During each capture iteration a new GUI appear and displays live data from the measurement equipment to the user, while the main capture code is running.
I'd like to do something like this:
for setting in settings:
measurement_equipment.start(setting)
gui = LiveDataStreamGUI(measurement_equipment)
gui.display()
measurement_equipment.capture_data(300) #may take hours
gui.close()
The main issue
I'd like the data capture code to be the main thread. However pyqt doesn't seems to allow this architecture, as its app.exec_() is a blocking call, allowing a GUI to be created only once per process (e.g., in gui.display() above).
An application is an executable process that runs on one or more foreground threads each of which can also start background threads to perform parallel operations or operations without blocking the calling thread. An application will terminate after all foreground threads have ended, therefore, you need at least one foreground thread which in your case is created when you call the app.exec_() statement. In a GUI application, this is the UI thread where you should create and display the main window and any other UI widget. Qt will automatically terminate your application process when all widgets are closed.
IMHO, you should try to follow the normal flow described above as much as possible, the workflow could be as follows:
Start Application > Create main window > Start a background thread for each calculation > Send progress to UI thread > Show results in a window after each calculation is finished > Close all windows > End application
Also, you should use ThreadPool to make sure you don't run out of resources.
Here is a complete example:
import sys
import time
import PyQt5
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtCore import QRunnable, pyqtSignal, QObject
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QDialog
class CaptureDataTaskStatus(QObject):
progress = pyqtSignal(int, int) # This signal is used to report progress to the UI thread.
captureDataFinished = pyqtSignal(dict) # Assuming your result is a dict, this can be a class, a number, etc..
class CaptureDataTask(QRunnable):
def __init__(self, num_measurements):
super().__init__()
self.num_measurements = num_measurements
self.status = CaptureDataTaskStatus()
def run(self):
for i in range(0, self.num_measurements):
# Report progress
self.status.progress.emit(i + 1, self.num_measurements)
# Make your equipment measurement here
time.sleep(0.1) # Wait for some time to mimic a long action
# At the end you will have a result, for example
result = {'a': 1, 'b': 2, 'c': 3}
# Send it to the UI thread
self.status.captureDataFinished.emit(result)
class ResultWindow(QWidget):
def __init__(self, result):
super().__init__()
# Display your result using widgets...
self.result = result
# For this example I will just print the dict values to the console
print('a: {}'.format(result['a']))
print('b: {}'.format(result['b']))
print('c: {}'.format(result['c']))
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
self.result_windows = []
self.thread_pool = QtCore.QThreadPool().globalInstance()
# Change the following to suit your needs (I just put 1 here so you can see each task opening a window while the others are still running)
self.thread_pool.setMaxThreadCount(1)
# You could also start by clicking a button, menu, etc..
self.start_capturing_data()
def start_capturing_data(self):
# Here you start data capture tasks as needed (I just start 3 as an example)
for setting in range(0, 3):
capture_data_task = CaptureDataTask(300)
capture_data_task.status.progress.connect(self.capture_data_progress)
capture_data_task.status.captureDataFinished.connect(self.capture_data_finished)
self.thread_pool.globalInstance().start(capture_data_task)
def capture_data_progress(self, current, total):
# Update progress bar, label etc... for this example I will just print them to the console
print('Current: {}'.format(current))
print('Total: {}'.format(total))
def capture_data_finished(self, result):
result_window = ResultWindow(result)
self.result_windows.append(result_window)
result_window.show()
class App(QApplication):
"""Main application wrapper, loads and shows the main window"""
def __init__(self, sys_argv):
super().__init__(sys_argv)
self.main_window = MainWindow()
self.main_window.show()
if __name__ == '__main__':
app = App(sys.argv)
sys.exit(app.exec_())
If you want your GUI to keep updating in realtime and to not be freezed, you have two main ways to do it:
Refresh the GUI from time to time calling QApplication.processEvents() inside your time consuming function.
Create a separate thread (I mean, QThread) where you run your time consuming function
My personal preference is to go for the latter way. Here is a good tutorial for getting started on how to do multi-threading in Qt.
Having a look at your code:
...
gui.display()
measurement_equipment.capture_data(300) #may take hours
gui.close()
...
it seems you are calling app.exec_ inside gui.display. Its very likely you will have to decouple both functions and call app.exec_ outside of gui.display and after calling capture_data. You will also have to connect the finished signal of the new thread to gui.close. It will be something like this:
...
gui.display() # dont call app.exec_ here
thread = QThread.create(measurement_equipment.capture_data, 300)
thread.finished.connect(gui.close)
app.exec_()
...
I hope this can help you and to not be late!!
You can have only One graphic GUI thread. This would imply to have some Threads to capture data and sync data with the graphic application when needed.
We need to know if the GUI data display is displaying realtime data or only oneshot.
We have a Pyxll app (Excel app written in python) that makes a bunch of requests to get data when the workbook is opened. We would like to display a loading bar to the user while the requests are being made and update the loading bar after each request returns.
I'm trying to use Tkinter to do this, but have run into issues. I can get a progress bar to pop up, but it blocks Excel from running until you close the window for the progress bar. I can't put it in a different thread because I want to be able to update the progress based on when the HTTP requests return. Is there an easy way to do this?
Here is my code so far. I have made a basic loading bar class:
import Tkinter as tk
import ttk
class OrderingProgressBar(tk.Tk):
def __init__(self, *args, **kwargs):
tk.Tk.__init__(self, *args, **kwargs)
# progress goes from 0-100 (for percentage)
self.progress = 0
self.max_progress = 100
self.progress_bar = ttk.Progressbar(self, orient="horizontal", length=200, mode="determinate", maximum=self.max_progress)
self.progress_bar.pack()
And then I have a macro that gets called to launch the app and start making requests.
def launch_ordering_terminal(ribbon):
"""Launch all of the apps required for the Ordering Terminal"""
ordering_progress_bar = OrderingProgressBar()
ordering_progress_bar.mainloop()
excel_utils.turn_off_excel_updates(xl_app())
launch_allocation_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_si_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_accounting_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_reports_builder(terminal_mode)
ordering_progress_bar.progress_bar.step(25)
excel_utils.turn_on_excel_updates(xl_app())
With this code, when I call the macro a loading bar pops up, but block Excel. If I close the window it continues. If I move the mainloop call to the end of launch_ordering_terminal, then the entire terminal loads, and then it pops up the loading bar. I can't get them to work at the same time.
Thanks in advance for the help!
Maintaining a GUI is a full time job that requires an endless loop, called the "mainloop". If you want to do something else in the meantime, you need to add it to the mainloop, or do it in a different thread. In your case I think a new thread would be easiest. Tkinter runs best in the main thread, so put your code in a child thread.
As a totally untested guess:
from threading import Thread
def do_stuff(ordering_progress_bar):
excel_utils.turn_off_excel_updates(xl_app())
launch_allocation_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_si_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_accounting_app(manager_id)
ordering_progress_bar.progress_bar.step(25)
launch_reports_builder(terminal_mode)
ordering_progress_bar.progress_bar.step(25)
excel_utils.turn_on_excel_updates(xl_app())
ordering_progress_bar.quit() # kill the GUI
def launch_ordering_terminal(ribbon):
"""Launch all of the apps required for the Ordering Terminal"""
ordering_progress_bar = OrderingProgressBar()
t = Thread(target=do_stuff, args=(ordering_progress_bar,))
t.start()
ordering_progress_bar.mainloop()
I have created a relatively complex PyQt program and am trying to implement threads so that when the program encounters a part of the program which is particularly CPU intensive, the GUI will remain refreshed and responsive throughout. Sadly though, I am having some difficulties with the threading.
I am using Python 2.7 for reasons that I don't believe to be relevant.
Anyway, the entire program runs within one class and calls upon a PyQt designer .ui file in order to display the actual GUI. When a particular button is pressed, in order to shred a file, it calls a function within that class that then starts a thread using the 'thread' module, yes, outdated, I know. The shredding function that is then called from this commences the shredding of the file. Throughout the shredding of the file, the actual shredding function interacts and adds bits to the GUI in order to keep the user up to date on what is happening.
During the execution of the function the GUI continues to be refreshed, however it does become a little laggy, I can cope with that. However, when that function is complete, instead of smoothly continuing and allowing the user to keep using the program, the program throws a complete hissy fit and simply just stops working and has to be closed.
Hopefully someone can assist me here. I would greatly appreciate as much detail as possible as I have been searching around for a way to cope with this for a good number of weeks now.
I am using PyQt4.
Here's a simple demo of threading in pyqt5. Qt has it's own threading class that works pretty well.
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import pyqtSignal
import sys
import time
class TheBoss(QtWidgets.QWidget):
def __init__(self, parent=None):
super(TheBoss, self).__init__(parent)
self.resize(300,200)
self.VL = QtWidgets.QVBoxLayout(self)
self.label = QtWidgets.QLabel()
self.VL.addWidget(self.label)
self.logger = Logger()
self.logger.sec_signal.connect(self.label.setText)
self.logger.start()
def closeEvent(self,event):
self.logger.terminate()
class Logger(QtCore.QThread):
sec_signal = pyqtSignal(str)
def __init__(self, parent=None):
super(Logger, self).__init__(parent)
self.current_time = 0
self.go = True
def run(self):
#this is a special fxn that's called with the start() fxn
while self.go:
time.sleep(1)
self.sec_signal.emit(str(self.current_time))
self.current_time += 1
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
app.setApplicationName("Thread Example")
window = TheBoss()
window.show()
sys.exit(app.exec_())
I would like to run pyglet in a separate thread so that I can implement a user interface for input without being blocked by pyglet.app.run().
import pyglet
class Window(pyglet.window.Window):
def __init__(self):
pyglet.window.Window.__init__(self, visible=True)
self.push_handlers(on_draw=self.on_draw)
self.im = pyglet.resource.image('image.jpg')
pyglet.app.run()
def on_draw(self):
self.clear()
import threading
class Thread(threading.Thread):
def run(self):
w = Window()
Running
Window()
works fine. However, running
t = Thread()
t.start()
results in Segmentation fault (core dumped), which is caused by the call to pyglet.resource.image(). Omitting that call eliminates the problem.
Specifically, what is causing this problem, and how can I correct it? More generally, what is the recommended way to render a window using pyglet while allowing for other program execution? Is there a better way to do this?