execute ping command with GUI

Question

While writing a GUI application in PyQt5 I encounter weird(for me) behavior. When I wanted to open an information window and start doing another thing after it fully loads.

Answer 1

As an option. Try it:

import sys
import os
from PyQt5.QtWidgets import QApplication,QMessageBox
from PyQt5.QtCore import QTimer

app = QApplication(sys.argv)

box = QMessageBox()
box.setText("Text")
box.show()

def osSystem():
    os.system("ping 8.8.8.8 ") 

QTimer.singleShot(20, osSystem )

#os.system("ping 8.8.8.8 ")


sys.exit(app.exec())

Answer 2

Here is a single-line solution:

from PyQt5.QtWidgets import QApplication,QMessageBox
import sys
import os
app = QApplication(sys.argv)

box = QMessageBox()
box.setText("Text")
box.show()
QApplication.processEvents() # <------------ this one
os.system("ping 8.8.8.8 ")

sys.exit(app.exec())

Answer 3

Although the solutions of S.Nick and Guimoute seems to work but the reality is that it has only made the window show a moment but if you want to interact with it you will see that it is frozen, for example try to move the window to check it. The os.system() task is blocking so it must be executed in another thread

import os
import sys
from PyQt5.QtWidgets import QApplication,QMessageBox

import threading
app = QApplication(sys.argv)

box = QMessageBox()
box.setText("Text")
box.show()

def task():
    os.system("ping 8.8.8.8 ") 
threading.Thread(target=task, daemon=True).start()
# or threading.Thread(target=os.system, args=("ping 8.8.8.8 ",), daemon=True).start()
sys.exit(app.exec_())

Or use QProcess:

import sys
import os
from PyQt5.QtWidgets import QApplication,QMessageBox
from PyQt5.QtCore import QProcess

app = QApplication(sys.argv)

box = QMessageBox()
box.setText("Text")
box.show()

def on_readyReadStandardOutput():
    print(process.readAllStandardOutput().data().decode(), end="")

process = QProcess()
process.start("ping", ["8.8.8.8"])
process.readyReadStandardOutput.connect(on_readyReadStandardOutput)
sys.exit(app.exec_())

Update

import os
import sys
from PyQt5 import QtCore, QtWidgets


class PingObject(QtCore.QObject):
    finished = QtCore.pyqtSignal()

    @QtCore.pyqtSlot()
    def start(self):
        os.system("ping 8.8.8.8")
        self.finished.emit()


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)

    box = QtWidgets.QMessageBox()
    box.setText("Text")
    box.show()
    thread = QtCore.QThread()
    thread.start()
    ping = PingObject()
    ping.moveToThread(thread)
    QtCore.QTimer.singleShot(0, ping.start)
    loop = QtCore.QEventLoop()
    ping.finished.connect(loop.quit)
    loop.exec_()
    print("finished ping")
    sys.exit(app.exec_())

Another Option:

import os
import sys
from PyQt5 import QtCore, QtWidgets


class Thread(QtCore.QThread):
    def run(self):
        response = os.popen("ping 8.8.8.8")
        for line in response.readlines():
            print(line)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)

    box = QtWidgets.QMessageBox()
    box.setText("Text")
    box.show()

    thread = Thread()
    thread.start()
    ret = app.exec_()
    thread.quit()
    thread.wait()
    sys.exit(ret)