How can I run 2 threads at the same time in pyqt?

Question

I am trying to read 2 different files at the same time using pyqt and threads but only one thread gets run out of the two. My code has 2 thread classes and each are responsible for reading their assigned files. How can I achieve this?

Here is what I've tried:

import sys
from PyQt4 import QtCore, QtGui
import subprocess
from time import sleep

class Thread1(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)

    def file_len(self):
        p = subprocess.Popen(['wc', '-l', 'file1.txt'], stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE)
        result, err = p.communicate()
        if p.returncode != 0:
            raise IOError(err)
        return int(result.strip().split()[0]) #returns 600 lines

    def run(self):
        self.emit(QtCore.SIGNAL('updateProgressBar(int)'), 0) ## Reset progressbar value
        file_in = "file1.txt"
        loading = 0
        x = float(100) / self.file_len()
        with open(file_in) as f:
            for line in f:
                loading += x
                print line
                self.emit(QtCore.SIGNAL('updateProgressBar(int)'), loading)
                sleep(0.15)

class Thread2(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)

    def file_len(self):
        p = subprocess.Popen(['wc', '-l', 'file2.txt'], stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE)
        result, err = p.communicate()
        if p.returncode != 0:
            raise IOError(err)
        return int(result.strip().split()[0]) #returns 2500 lines

    def run(self):
        self.emit(QtCore.SIGNAL('updateProgressBar(int)'), 0)  ## Reset progressbar value
        file_in = "file2.txt"
        loading = 0
        x = float(100) / self.file_len()
        with open(file_in) as f:
            for line in f:
                loading += x
                print line
                self.emit(QtCore.SIGNAL('updateProgressBar(int)'), loading)
                sleep(0.001)



class AppView(QtGui.QDialog):

    def __init__(self, parent=None):
        super(AppView, self).__init__(parent)
        self.resize(400, 400)
        self.buttonStart = QtGui.QPushButton(self)
        self.buttonStart.setText("Start")
        self.buttonStart.clicked.connect(self.start)

        self.progress = QtGui.QProgressBar(self)
        self.progress2 = QtGui.QProgressBar(self)

        verticalLayout = QtGui.QVBoxLayout(self)
        verticalLayout.addWidget(self.buttonStart)
        verticalLayout.addWidget(self.progress)
        verticalLayout.addWidget(self.progress2)
        self.progressView = Thread1()
        self.progressView2 = Thread2()
        self.connect(self.progressView, QtCore.SIGNAL("updateProgressBar(int)"), self.updateProgressBar)
        self.connect(self.progressView2, QtCore.SIGNAL("updateProgressBar2(int)"), self.updateProgressBar2)
        self.start()

    def updateProgressBar(self, percent):
        self.progress.setValue(percent)

    def updateProgressBar2(self, percent):
        self.progress2.setValue(percent)


    def start(self):
        self.progressView.start()
        self.progressView2.start()

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    appview = AppView()
    appview.show()
    sys.exit(app.exec_())

Answer 1

Perhaps the method run of thread2 must call updateProgressBar2, not updateProgressBar?