“GUI becomes unresponsive after clicking the button”

Question

I\'ve designed a GUI for my application and after a button click, I\'ve connected a custom function of mine wherein I call a bash command to run 2 Python scripts simultaneously.

Answer 1

The function subprocess.check_output() is blocking, so it will prevent the event-loop of the GUI from doing its job by freezing your application, instead you should use QProcess:

class MainApp(QtWidgets.QMainWindow, mainui.Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainApp, self).__init__(parent)
        self.setupUi(self)

        self._process = QtCore.QProcess(self)
        self._process.readyReadStandardOutput.connect(self.on_readyReadStandardOutput)
        self._process.setProcessChannelMode(QtCore.QProcess.ForwardedChannels)
        self._process.setProgram('bash')
        self._process.setArguments(['-c', 'python3 guiGO.py & python3 liveSpectogram.py &'])

        self.exitapp()
        self.startApp()

    # read prints
    def on_readyReadStandardOutput(self):
        self.output = self._process.readAllStandardOutput()
        print(self.output)

    def startApp(self):
        self.start.clicked.connect(self._process.start)

    def exitapp(self):
        self.exit.clicked.connect(self.close)

Update:

If you want to kill the python scripts you must do it through bash, with the pkill command, since this was the one that launched them. And in what part of the code should you call pkill ?, a possible part is the closeEvent method.

from PyQt5 import QtCore, QtWidgets

class MainApp(QtWidgets.QMainWindow): #, mainui.Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainApp, self).__init__(parent)
        self.setupUi(self)

        self._scripts = ("guiGO.py", "liveSpectogram.py")
        self._processes = []
        for script in self._scripts:
            process = QtCore.QProcess(self)
            process.readyReadStandardOutput.connect(self.on_readyReadStandardOutput)
            process.setProcessChannelMode(QtCore.QProcess.ForwardedChannels)
            process.setProgram('bash')
            process.setArguments(['-c', 'python3 {}'.format(script)])
            self._processes.append(process)

        self.exitapp()
        self.startApp()

    # read prints
    def on_readyReadStandardOutput(self):
        self.output = self.sender().readAllStandardOutput()
        print(self.output)

    def startApp(self):
        for process in self._processes:
            self.start.clicked.connect(process.start)

    def exitapp(self):
        self.exit.clicked.connect(self.close)

    def closeEvent(self, event):
        for script in self._scripts:
            QtCore.QProcess.startDetached("bash", ["-c", "pkill -f {}".format(script)])
        super(MainApp, self).closeEvent(event)

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainApp()
    w.show()
    sys.exit(app.exec_())