I would like to show progress of calculation if in my GUI. To do so I would like to update my PyQt4 label each time a calculation is made. I know that I am supposed to use thread to do it, but it doesn't work. Nothing changes, and after while loop is complete, the label is updated to "100%".Even though the thread is working the value still won't update smoothly. There are comments in my code explaining what is what. Please help me :)
from PyQt4 import QtGui, QtCore
import time
class MyThread(QtCore.QThread):
trigger = QtCore.pyqtSignal(int)
def __init__(self, progress, parent=None):
super(MyThread, self).__init__(parent)
self.progress = progress #progress is a PyQt4 label object
def update_progress(self, value):
self.progress.setText(QtGui.QApplication.translate("Dialog", "Progress: %s " % value, None))
print "I was called", value
print self.progress #prints <PyQt4.QtGui.QLabel object at 0x0000000008151708>
#as you can see the object is passed all right
def run(self, value):
self.trigger.emit(value)
class Calculus:
def __init__(self):
print "object created"
#staticmethod
def euler(b,h,progress):
#progress is a PyQt4 label object, b and h are some integers
actions_done = 0
actions_number = b / h
thread = MyThread(progress)#create a thread
thread.trigger.connect(thread.update_progress)#connect it with a update function
thread.start()#start the thread
while t <= b:
actions_done+=1
progress_value = (actions_done/actions_number)*100
thread.run(progress_value)#emit signal?
t += h
thread.terminate()
#EDIT, here is my solution but with memory leaking problem
from PyQt4 import QtGui
class Calculus:
def __init__(self):
print "object created"
#staticmethod
def update_progress(self,value,ui_object):
ui_object.setText(QtGui.QApplication.translate("Dialog", "Progress: %s %%" % value, None))
#MEMORY LEAK WHEN UPDATING TOO MUCH (H=0.0001 AND B=1000)
QtGui.QApplication.processEvents() #update gui for pyqt
#staticmethod
def euler(b,h,progress):
actions_done = 0
actions_number = b * (1./h) #t = t+h. When h = 0.01 we need to perform t=t+h 100(1/h) times to get 1.
#when t varies from 0 to b, then we need to multiply this 1 * b(end time)
#so we get b * (1/h) as a number of actions to perform
scale = actions_number * 0.01
while t <= b:
actions_done+=1
progress_value = (actions_done/actions_number)*100
if (actions_done % scale == 0):
Calculus.update_progress(None,progress_value, progress)
t += h
Calling thread.run() in the way that you are does not do what you think it does. Currently it is simply executing the thread.run() method in the main thread.
It is the call to thread.start() which starts the thread, and automatically calls the thread.run() method. As such, you need the while loop inside the thread.run() method.
This is because you want to pass complete control over to the thread, and finish the euler method so that control can be returned to the GUI event loop (so it can process redraws, and the method to update the progress bar) as soon as possible. You should not be trying to manage the threads execution from the main thread.
Related
I am building a GUI on python and pyqt.
The GUI has a lot of pushbuttons, generated through class LED, meaning each led has 3 buttons, for an n number of leds.
In a few of the buttons, I want an effect that changes the opacity of the pushbutton, in a loop from 0 to 1 and back again, so it disappears and appears. I need only one process to manage all, so the effect starts at same time for every button and all blink at the same time.
I've managed to achieve that, through qgraphicseffect in a thread, iterating through a list.
The problem is that after a few minutes, the effect stops, although the thread is still running (print(opacity_level)). more pushbuttons with the effect makes even shorter duration. Clicking any button, even others without effect, restarts the gui animation.
My small research in threading on pyqt made me implement this thread manager, although I do not fully understand it.
class WorkerSignals(QtCore.QObject):
finished = QtCore.pyqtSignal()
error = QtCore.pyqtSignal(tuple)
result = QtCore.pyqtSignal(object)
progress = QtCore.pyqtSignal(tuple)
class Worker(QtCore.QRunnable):
'''
Worker thread
Inherits from QRunnable to handler worker thread setup, signals and wrap-up.
'''
def __init__(self, fn, *args, **kwargs):
super(Worker, self).__init__()
# Store constructor arguments (re-used for processing)
self.fn = fn
self.args = args
self.kwargs = kwargs
self.signals = WorkerSignals()
# Add the callback to our kwargs
self.kwargs['progress_callback'] = self.signals.progress
#pyqtSlot()
def run(self):
'''
Initialise the runner function with passed args, kwargs.
'''
# Retrieve args/kwargs here; and fire processing using them
try:
result = self.fn(*self.args, **self.kwargs)
except:
traceback.print_exc()
exctype, value = sys.exc_info()[:2]
self.signals.error.emit((exctype, value, traceback.format_exc()))
else:
self.signals.result.emit(result) # Return the result of the processing
finally:
self.signals.finished.emit() # Done
Next the leds class
class LEDs:
def __init__(self,name,group,frame):
self.opacity_effect = QtWidgets.QGraphicsOpacityEffect()
self.button_auto = QtWidgets.QPushButton()
self.button_auto.setObjectName("button_auto_neutral")
self.button_auto.clicked.connect(lambda state, x=self: self.AutoMode())
def AutoMode(self):
print(self.name,"Automode")
if len(settings.blink) ==0: # start thread only if no previous thread, both thread and
this reference the size of settings.blink, so not ideal.
print("start thread")
settings.ledAutomode()
settings.blink.append(self)
And finally the settings class, which has the thread with the effect performing action. There is a second thread, which handles the icon of the button, accordingly with a timetable.
class Settings:
def __init__(self):
self.blink=[]
def ledAutomode(self):
def blink(progress_callback):
print("opacity")
op_up=[x/100 for x in range(0,101,5)]
op_down=op_up[::-1]; op_down=op_down[1:-1]; opacity=op_up+op_down
while len(self.blink) !=0:
for i in opacity:
print(i)
QtCore.QThread.msleep(80)
for led in self.blink:
led.opacity_effect.setOpacity(i)
def timeCheck(progress_callback):
while len(self.blink) != 0:
QtCore.QThread.msleep(500)
for led in self.blink:
matrix = [v for v in settings.leds_config[led.group][led.name]["Timetable"]]
matrix_time=[]
...
# some code
...
if sum(led_on_time):
led.button_auto.setObjectName("button_auto_on")
led.button_auto.setStyleSheet(ex.stylesheet)
else:
led.button_auto.setObjectName("button_auto_off")
led.button_auto.setStyleSheet(ex.stylesheet)
QtCore.QThread.msleep(int(30000/len(self.blink)))
worker = Worker(blink) # Any other args, kwargs are passed to the run function
ex.threadpool.start(worker)
worker2 = Worker(timeCheck) # Any other args, kwargs are passed to the run function
ex.threadpool.start(worker2)
So, perhaps a limitation on qgraphicseffect, or some problem with the thread (although its keeps printing), or I made some error.
I've read about subclassing the qgraphicseffect but I don't know if that solves the problem.
If anyone has another implementation, always eager to learn.
Grateful for your time.
Widgets are not thread-safe.
They cannot be created nor accessed from external threads. While it "sometimes" works, doing it is wrong and usually leads to unexpected behavior, drawing artifacts and even fatal crash.
That said, you're making the whole process incredibly and unnecessarily convoluted, much more than it should be, most importantly because Qt already provides both timed events (QTimer) and animations.
class FadeButton(QtWidgets.QPushButton):
def __init__(self):
super().__init__()
self.effect = QtWidgets.QGraphicsOpacityEffect(opacity=1.0)
self.setGraphicsEffect(self.effect)
self.animation = QtCore.QPropertyAnimation(self.effect, b'opacity')
self.animation.setStartValue(1.0)
self.animation.setEndValue(0.0)
self.animation.setDuration(1500)
self.animation.finished.connect(self.checkAnimation)
self.clicked.connect(self.startAnimation)
def startAnimation(self):
self.animation.stop()
self.animation.setDirection(self.animation.Forward)
self.animation.start()
def checkAnimation(self):
if not self.animation.value():
self.animation.setDirection(self.animation.Backward)
self.animation.start()
else:
self.animation.setDirection(self.animation.Forward)
If you want to synchronize opacity amongst many widgets, there are various possibilities, but a QVariantAnimation that updates all opacities is probably the easier choice:
class LEDs(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
layout = QtWidgets.QHBoxLayout(self)
self.animation = QtCore.QVariantAnimation()
self.animation.setStartValue(1.0)
self.animation.setEndValue(0.0)
self.animation.setDuration(1500)
self.animation.valueChanged.connect(self.updateOpacity)
self.animation.finished.connect(self.checkAnimation)
self.buttons = []
for i in range(3):
button = QtWidgets.QPushButton()
self.buttons.append(button)
layout.addWidget(button)
effect = QtWidgets.QGraphicsOpacityEffect(opacity=1.0)
button.setGraphicsEffect(effect)
button.clicked.connect(self.startAnimation)
# ... as above ...
def updateOpacity(self, opacity):
for button in self.buttons:
button.graphicsEffect().setOpacity(opacity)
Note that you shouldn't change the object name of a widget during runtime, and doing it only because you want to update the stylesheet is wrong. You either use a different stylesheet, or you use the property selector:
QPushButton {
/* default state */
background: #ababab;
}
QPushButton[auto_on="true"] {
/* "on" state */
background: #dadada;
}
class FadeButton(QtWidgets.QPushButton):
def __init__(self):
super().__init__()
# ...
self.setProperty('auto_on', False)
def setAuto(self, state):
self.setProperty('auto_on', state)
self.setStyleSheet(self.styleSheet())
I have a number of certain objects which need to run a specific function at specific ever-changing intervals, again and again, until they decide they are done.
For example, one object may need to wait 30 seconds, run, wait 60 seconds, run, wait 10 seconds, run... You get the point, and this could be going on for 30-120 different objects, running the exact same kind of function.
I was thinking that simply having a function that sleeps for the exact interval would solve my problem, but, correct me if I'm wrong, I remembered that thread pools can only run a certain number of threads at any given time (12 for me). How do I get around this limit?
class Thing(object):
def getCurrentPeriod(self):
return random.randint(5, 30) # Some ever changing period of time
def refresh(self):
doThings() # A long running task that is disk and network intensive
def waitRefresh(self):
period = self.getCurrentPeriod()
time.sleep(period) # Wait that period out
self.refresh()
return self.needRefresh()
# Boolean if it needs to restart - Not sure about how to reschedule,
# or specifically where to connect the worker emit when it finishes
# to make sure this *specific* Thing obj gets it's waitRefresh func called again.
class App(QMainWindow):
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
self.threadpool = QThreadPool()
# Add initial objects to pool (other portions of app may add more over time)
for thing in self.acquireThings():
worker = Worker(thing.waitRefresh)
self.threadpool.start(worker)
Doesn't include the WorkerSignals class nor the QRunnable subclass, this example includes what I usually do. The example is tackling the same problem, but in a (most likely) inefficient way.
edit: New example with complete working example of how time.sleep does not pause the thread and allow others to work. I feel that async may be the only implementation, but is there a quick fix so I don't have to alter my entire app?
Here's what it looks like when you try to sleep more than 12 threads.
The ultimate solution came when I decided to actually try the QTimer class. Perhaps there are more optimized solutions, but this one seems to hit all the checkboxes, even if it's worryingly simple.
import random
import time
import traceback
from functools import partial
from PyQt5.QtCore import *
from PyQt5.QtGui import QFont
from PyQt5.QtWidgets import *
class WorkerSignals(QObject):
"""
Represents the signals a Worker can emit.
"""
finished = pyqtSignal()
starting = pyqtSignal(int) # ID of thread
result = pyqtSignal(tuple) # Tuple refresh result, result and ID
class Worker(QRunnable):
"""
A worker designed to tell when it's starting, when it's finished and the result.
Designed to work around Thread.refresh().
"""
def __init__(self, fn, thread_id, *args, **kwargs):
super(Worker, self).__init__()
# Store constructor arguments (re-used for processing)
self.fn = fn
self.id = thread_id
self.args = args
self.kwargs = kwargs
self.signals = WorkerSignals()
#pyqtSlot()
def run(self):
"""
Runs a given method, and emits the result with the Worker's coordinated ID.
"""
try:
self.signals.starting.emit(self.id) # Thread is now finally ready to work.
result = self.fn(*self.args, **self.kwargs) # Refresh Thread!
self.signals.result.emit(result) # Thread is finished, emit result tuple.
except:
traceback.print_exc()
finally:
self.signals.finished.emit() # Done
class Thread(object):
"""
Basic Rules for a Thread Object:
Cannot store the next timestamp on the object (it's a database object, I don't believe it's good practice
to be creating sessions over and over to simply read/write the access time.
ID and Active are allowed as booleans.
"""
i = -1
def __init__(self):
self.id = Thread.nextID()
self.active = True
self.refreshes = 0
def refresh(self) -> tuple:
"""
'Refreshes' a thread. Waits a specific period, then decides whether Thread object should be deactivated or
returned from additional refreshes. Chance of deactivation lowers with each refresh.
:return: The refresh result, a tuple with a boolean and the thread's ID (for identifying it later)
"""
# Represents my SQL Alchemy Model's refresh() function
self.refreshes += 1
time.sleep(random.randint(2, 5))
if random.random() <= max(0.1, 1.0 - ((self.refreshes + 5) / 10)):
self.active = False
return self.active, self.id
#staticmethod
def getRefreshTime() -> float:
"""
Represents the amount of time before a thread should be refreshed.
Should NOT be used to determine whether the thread is still active or not.
:return: The time period that should be waited.
"""
return random.uniform(10, 300)
#staticmethod
def nextID() -> int:
"""
Returns integer thread IDs in sequence to remove possibility of duplicate IDs.
:return: Integer Thread ID
"""
Thread.i += 1
return Thread.i
def __repr__(self):
return f'Thread(id={self.id} active={self.active})'
class MainWindow(QMainWindow):
"""
GUI containing a Label, Button and ListWidget showing all the active sleeping/working threads.
Manages a threadpool, a number of background singleshot timers, etc.
"""
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
# Widgets Setup
layout = QVBoxLayout()
self.list = QListWidget()
self.l = QLabel("Total Active: 0")
self.button = QPushButton("Refresh List")
self.button.pressed.connect(self.refreshList)
self.button.setDisabled(True)
layout.addWidget(self.l)
layout.addWidget(self.button)
layout.addWidget(self.list)
w = QWidget()
w.setLayout(layout)
self.setCentralWidget(w)
self.show()
# Periodically add threads to the pool.
self.poolTimer = QTimer()
self.poolTimer.setInterval(5_000)
self.poolTimer.timeout.connect(self.addThreads)
# Threading Setup
self.threadpool = QThreadPool()
print("Multithreading with maximum %d threads" % self.threadpool.maxThreadCount())
self.active, self.threads = {}, {}
# Add a number of threads to start with.
for _ in range(random.randint(5, 16)):
self.setupThread(Thread())
self.poolTimer.start()
def refreshList(self):
"""
Refreshes the ListWidget in the GUI with all the active/sleeping/working threads.
"""
self.list.clear()
bold = QFont()
bold.setBold(True)
active = 0
for thread in self.threads.values():
item = QListWidgetItem(
f'Thread {thread.id}/{thread.refreshes}')
# Bold a thread if it's working
if self.active[thread.id]:
active += 1
item.setFont(bold)
self.list.addItem(item)
self.l.setText(f'Total Active: {active}/{len(self.threads)}')
def refreshResult(self, result) -> None:
"""
When a thread is finished, the result determines it's next course of action, which is either
to return to the pool again, or delete itself.
:param result: A tuple containing the result (bool) and the connected Thread ID.
"""
self.active[result[1]] = False
if result[0]:
print(f'Restarting Thread {result[1]}')
self.setupThread(self.threads[result[1]]) # Add by ID, which would normally be a database GET
else:
print(f'Thread {result[1]} shutting down.')
del self.active[result[1]]
del self.threads[result[1]]
self.refreshList()
def updateActivity(self, thread_id) -> None:
"""
Connected to the starting signal, helps signal when a thread is actually being refreshed.
:param thread_id: The Thread ID
"""
print(f'Thread {thread_id} is now active/working.')
self.active[thread_id] = True
def refresh(self, thread):
"""
Adds a new worker to the threadpool to be refreshed.
Can't be considered a real start to the thread.refresh function, as the pool has a max of 12 workers at any time.
The 'starting' signal can tell us when a specific thread is actually being refreshed, and is represented
as a Bold element in the list.
:param thread: A thread instance.
"""
print(f'Adding Thread {thread.id} to the pool.')
worker = Worker(thread.refresh, thread_id=thread.id)
worker.signals.result.connect(self.refreshResult)
worker.signals.starting.connect(self.updateActivity)
self.threadpool.start(worker)
# self.active[thread.id] = True
self.refreshList()
def setupThread(self, thread) -> None:
"""
Adds a new timer designated to start a specific thread.
:param thread: A thread instance.
"""
self.active[thread.id] = False
self.threads[thread.id] = thread
t = QTimer()
period = thread.getRefreshTime()
t.singleShot(period * 1000, partial(self.refresh, thread=thread))
print(f'Thread {thread.id} will start in {period} seconds.')
self.refreshList()
def addThreads(self):
"""
Adds a number of threads to the pool. Called automatically every couple seconds.
"""
add = max(0, 30 + random.randint(-5, 5) - len(self.threads))
if add > 0:
print(f'Adding {add} thread{"s" if add > 1 else ""}.')
for _ in range(add):
self.setupThread(Thread())
app = QApplication([])
window = MainWindow()
app.exec_()
When a Thread is requested, a Timer is created and singleShot is fired on an extra function that will add it to the threadpool. This threadpool can handle up to 12 refreshing continious 'refreshing' threads, and signals allow the GUI to update the moment a change is found.
Thousands of 'Thread' objects can be waiting and it seems singleShot is capable of adding them to the pool exactly when they need to be.
Signals help differentiate when a thread is sleeping, working and active (but inactive Thread objects are immediately removed).
The only caveats I can think of with this program is:
1) Can a QThread implementation beat it?
2) What happens to the QTimer once it's singleshot function has executed and fired? Will they be properly GC'd, or can thousands build up in the background consuming resources?
I made a Python turtle program that recursively generated a fractal tree, but, since it often took a few hours to fully draw, I wanted to try to use multithreading to have multiple turtles working together.
I was able to get two turtles moving at the same time, but, in this much more complex situation, everything seemed to fall apart. I've tried this many different ways, and thought this final solution would be the one, but it just throws a bunch of errors.
Here's my code:
import turtle
import threading
from queue import Queue
class Location:
def __init__(self, xpos=0, ypos=0, heading=90):
self.xpos = xpos
self.ypos = ypos
self.heading = heading
def getx(self):
return self.xpos
def gety(self):
return self.ypos
def geth(self):
return self.heading
class Turtle(turtle.Turtle):
def tolocation(self, location):
self.penup()
self.setx(location.getx())
self.sety(location.gety())
self.setheading(location.geth())
self.pendown()
def get_location(self):
return Location(self.xcor(), self.ycor(), self.heading())
def draw_tree(self, startpos=Location(), size=100):
tm.q.put(self.tolocation(startpos))
for _ in range(size):
tm.q.put(self.forward(1))
for _ in range(45):
tm.q.put(self.right(1))
t2 = Turtle()
t2.speed(0)
tm.new_thread(t2.draw_tree, self.get_location(), size / 2)
for _ in range(90):
tm.q.put(self.left(1))
tm.new_thread(self.draw_tree, self.get_location(), size / 2)
class ThreadManager:
def __init__(self):
self.q = Queue()
self.threads = []
def new_thread(self, func, *args):
self.threads.append(threading.Thread(target=func, args=(args,)))
self.threads[-1].daemon = True
self.threads[-1].start()
def process_queue(self, scr):
while not self.q.empty():
(self.q.get())(1)
if threading.active_count() > 1:
scr.ontimer(self.process_queue(scr), 100)
tm = ThreadManager()
scr = turtle.Screen()
t1 = Turtle()
t1.speed(0)
tm.new_thread(t1.draw_tree)
tm.process_queue(scr)
scr.exitonclick()
Can anyone give me an idea of where I went wrong here? The error messages say something along the lines of the recursion going too deep when process_queue calls itself. Am I using scr.ontimer() wrong?
There are several problems with your code:
draw_tree() doesn't have a base case to stop it's (conceptual)
recursion, it just keeps creating new threads.
Each call to draw_tree() divides size in half using floating
division so range(size) will fail as range() can only take ints.
Your calls to self.get_location() are not valid as it tells you
where the turtle is, not where it will be once the main thread
finishes processing outstanding graphics commands. You have to
compute where you will be, not look where you are.
This call, tm.q.put(self.tolocation(startpos)) isn't valid -- you
either need to do tm.q.put(self.tolocation, startpos) or call
tm.q.put() on each command inside self.tolocation().
You can't create new turtles anywhere but the main thread, as they
invoke tkinter on creation and that'll be on the wrong (not main)
thread. In my rework below, I simply preallocate them.
args=(args,) is incorrect -- should be args=args as args
is already in the correct format.
You don't need to create two new threads at each branching point, just
one. The new turtle goes one way, the old turtle continues on the
other.
Below is my rework of your code to address the above and other issues:
import math
import threading
from queue import Queue
from turtle import Turtle, Screen
class Location:
def __init__(self, xpos=0, ypos=0, heading=90):
self.xpos = xpos
self.ypos = ypos
self.heading = heading
def clone(self):
return Location(self.xpos, self.ypos, self.heading)
class Terrapin(Turtle):
def tolocation(self, location):
tm.q.put((self.penup,))
tm.q.put((self.setx, location.xpos))
tm.q.put((self.sety, location.ypos))
tm.q.put((self.setheading, location.heading))
tm.q.put((self.pendown,))
def draw_tree(self, startpos, size=100):
if size < 1:
return
self.tolocation(startpos)
tm.q.put((self.forward, size))
angle = math.radians(startpos.heading)
startpos.xpos += size * math.cos(angle)
startpos.ypos += size * math.sin(angle)
tm.q.put((self.right, 45))
startpos.heading -= 45
tm.new_thread(pond.get().draw_tree, startpos.clone(), size / 2)
tm.q.put((self.left, 90))
startpos.heading += 90
self.draw_tree(startpos, size / 2)
pond.put(self) # finished with this turtle, return it to pond
class ThreadManager:
def __init__(self):
self.q = Queue()
self.threads = Queue()
def new_thread(self, method, *arguments):
thread = threading.Thread(target=method, args=arguments)
thread.daemon = True
thread.start()
self.threads.put(thread)
def process_queue(self):
while not self.q.empty():
command, *arguments = self.q.get()
command(*arguments)
if threading.active_count() > 1:
screen.ontimer(self.process_queue, 100)
screen = Screen()
# Allocate all the turtles we'll need ahead as turtle creation inside
# threads calls into Tk which fails if not running in the main thread
pond = Queue()
for _ in range(100):
turtle = Terrapin(visible=False)
turtle.speed('fastest')
pond.put(turtle)
tm = ThreadManager()
tm.new_thread(pond.get().draw_tree, Location())
tm.process_queue()
screen.exitonclick()
if instead of large steps:
tm.q.put((self.right, 45))
you want to break down graphic commands into small steps:
for _ in range(45):
tm.q.put((self.right, 1))
that's OK, I just wanted to get the code to run. You need to figure out if this gains you anything.
I have created a program to generate data points of functions that I later plot. The program takes a class which defines the function, creates a data outputting object which when called generates the data to a text file. To make the whole process faster I put the jobs in threads, however when I do, the data generated is not always correct. I have attached a picture to show what I mean:
Here are some of the relevant bits of code:
from queue import Queue
import threading
import time
queueLock = threading.Lock()
workQueue = Queue(10)
def process_data(threadName, q, queue_window, done):
while not done.get():
queueLock.acquire() # check whether or not the queue is locked
if not workQueue.empty():
data = q.get()
# data is the Plot object to be run
queueLock.release()
data.parent_window = queue_window
data.process()
else:
queueLock.release()
time.sleep(1)
class WorkThread(threading.Thread):
def __init__(self, threadID, q, done):
threading.Thread.__init__(self)
self.ID = threadID
self.q = q
self.done = done
def get_qw(self, queue_window):
# gets the queue_window object
self.queue_window = queue_window
def run(self):
# this is called when thread.start() is called
print("Thread {0} started.".format(self.ID))
process_data(self.ID, self.q, self.queue_window, self.done)
print("Thread {0} finished.".format(self.ID))
class Application(Frame):
def __init__(self, etc):
self.threads = []
# does some things
def makeThreads(self):
for i in range(1, int(self.threadNum.get()) +1):
thread = WorkThread(i, workQueue, self.calcsDone)
self.threads.append(thread)
# more code which just processes the function etc, sorts out the gui stuff.
And in a separate class (as I'm using tkinter, so the actual code to get the threads to run is called in a different window) (self.parent is the Application class):
def run_jobs(self):
if self.running == False:
# threads are only initiated when jobs are to be run
self.running = True
self.parent.calcsDone.set(False)
self.parent.threads = [] # just to make sure that it is initially empty, we want new threads each time
self.parent.makeThreads()
self.threads = self.parent.threads
for thread in self.threads:
thread.get_qw(self)
thread.start()
# put the jobs in the workQueue
queueLock.acquire()
for job in self.job_queue:
workQueue.put(job)
queueLock.release()
else:
messagebox.showerror("Error", "Jobs already running")
This is all the code which relates to the threads.
I don't know why when I run the program with multiple threads some data points are incorrect, whilst running it with just 1 single thread the data is all perfect. I tried looking up "threadsafe" processes, but couldn't find anything.
Thanks in advance!
Does any one know how to call a def form a thread.
Clock Program:
import sys
from tkinter import *
from tkinter import messagebox
from tkinter import filedialog
from time import sleep
import threading
class MyThread ( threading.Thread ):
def mclock(): # function that it can't call
x = 1
z = 0
while x != -1:
Label(mGui,text = str(x) + "second(s)").pack()
x = x+1
sleep(1)
if x == 60:
x = 1
z = z+1
Label(mGui, text= str(z) + " minute(s) has past.").pack()
return
return
MyThread().start()
mGui = Tk()
mGui.geometry("300x200+100+100")
mGui.title("Jono's Clock")
menubar = Menu(mGui)
filemenu = Menu(menubar, tearoff = 0)
filemenu.add_command(label = "Clock",command = mclock) # can't use function
menubar.add_cascade(label = "File",menu = filemenu)
mGui.config(menu = menubar)
mGui.mainloop()
If any one sees any other errors please state. I am also using windows 7 and python 3.3.
There are several syntax errors in the code you've posted, and I'm not sure exactly what you intended with them, so here's an overview of how to run stuff from threads.
If you want your thread to run your own code from a custom thread class, the usual way to do that is to put the code in a method named run, which will be executed automatically when the thread is started:
import threading
class MyThread(threading.Thread):
def run(self):
# do your stuff here
print("Hello World")
MyThread().start()
Alternatively, if you don't need a class, you can create your function at the top level of your module, and pass it as an argument to threading.Thread's constructor:
def my_function():
print("Hello World")
threading.Thread(target=my_function).start()
Note that you often want to keep a reference to the thread object, rather than letting it go as the code above does. This requires you to use two lines to create and then start the thread:
thread = MyThread() # or the alternative version
thread.start()
This lets you later do:
thread.join()
Which ensures that the thread has finished its work.