The context: I'm building a Graphical Interface with Qt creator and the "behaviour" file in python. A test version of my GUI is:
The expected behaviour:
I am running 2 different threads which are referred to the same function with different input arguments. With the SELECTOR button I can assign the value of 1 or 2 to a variable (and display it)
The button Start thread enables the correct thread to start (the first time).
The loop should be turned off by the stop button by modifying the global running
variable.
This is my code
# -*- coding: utf-8 -*-
from PyQt4 import QtCore, QtGui, uic
import sys
import threading
import time
import Queue
running = False
first_thread = None
second_thread = None
form_class = uic.loadUiType("simple2.ui")[0]
q = Queue.Queue()
select = 0
def action(string, queue): #function called by threads
global running
while(running):
phrase = string
if queue.qsize() < 10:
queue.put(phrase)
#else:
# print queue.qsize()
class MyWindowClass(QtGui.QMainWindow, form_class):
def __init__(self, parent=None):
QtGui.QMainWindow.__init__(self, parent)
self.setupUi(self)
#buttons
self.startButton.clicked.connect(self.start_clicked)
self.stopButton.clicked.connect(self.stop_clicked)
self.selector.clicked.connect(self.sel_click)
#variables
self.first = False
self.second = False
#queue
self.timer = QtCore.QTimer(self)
self.timer.timeout.connect(self.update_phrase)
self.timer.start(1)
def start_clicked(self): #start button callback
global select
if select > 0:
global running
running = True
print "started"
if (not self.first) & (select == 1):
first_thread.start()
self.first = True
if (not self.second) & (select == 2):
second_thread.start()
self.second = True
self.startButton.setEnabled(False)
self.startButton.setText('Starting...')
def stop_clicked(self): #stop button callback
global running
running = False
print "stopped"
self.startButton.setEnabled(True)
self.startButton.setText('Start Thread')
def sel_click(self): #selector button callback
global select
if select < 2:
select = select + 1
else:
select = 1
self.thread_counter.setText(str(select))
def update_phrase(self): #looping function
global running
if (not q.empty()) & running:
self.startButton.setText('Thread on')
abc = q.get()
print abc
def closeEvent(self, event):
global running
running = False
if __name__ == "__main__":
first_thread = threading.Thread(target=action, args = ("first", q))
second_thread = threading.Thread(target=action, args = ("second", q))
app = QtGui.QApplication(sys.argv)
w = MyWindowClass(None)
w.setWindowTitle('Multiple threads test in python')
w.show()
app.exec_()
For now, each thread should simple print on terminal their arguments ("First" or "Second"). If threads are started for the first time, my code works. But I would like to switch between threads infinite times.
Since threads cannot be stopped, is there a way to "pause" them?
I cannot find a solution, I hope someone will help me also with a piece of code. Thank you in advance