Open a PyQt dialog from c++ QMainWindow

[marceloarguello700]

Hi, I have a program write in C++, is a QMainWindow,
wich some QDialogs also writen in C++, now i need to
use some code packages from python.

Then i want to open a PyQt5 QDialog from c++,
The python file is named dlgFromPython.py

import sys
from PyQt5.QtWidgets import (QDialog, QVBoxLayout, QDialogButtonBox, QDateTimeEdit, QApplication)
from PyQt5.QtCore import Qt, QDateTime
from PyQt5 import QtCore, QtWidgets

class dlgDateTime(QDialog):
    def __init__(self, parent = None):
        super().__init__()
        #super(dlgDateTime, self).__init__(parent)
        layout = QVBoxLayout(self)
        # nice widget for editing the date
        self.datetime = QDateTimeEdit(self)
        self.datetime.setCalendarPopup(True)
        self.datetime.setDateTime(QDateTime.currentDateTime())
        layout.addWidget(self.datetime)

        # OK and Cancel buttons
        self.buttons = QDialogButtonBox(
            QDialogButtonBox.Ok | QDialogButtonBox.Cancel,
            Qt.Horizontal, self)
        layout.addWidget(self.buttons)

        self.buttons.accepted.connect(self.accept)
        self.buttons.rejected.connect(self.reject)

    # get current date and time from the dialog
    def dateTime(self):
        return self.datetime.dateTime()

def fTestPrint():
    print("fTestPrint")
		
def fOpenDlg():
    print("fOpenDlg")
    app = QApplication(sys.argv)
    dlg = dlgDateTime()
    dlg.exec_()
	
if __name__ == '__main__':
    fTestPrint()
    fOpenDlg()

When I run the script from IDLE it work ok, the dialog appear.
But when i try from c++ the program crash or nothing happen.

void dlgPythonTest::sltTest3()
{
  // initialize python
  Py_Initialize();
  PyObject* mMainModule = PyImport_AddModule( "__main__" ); 
  PyObject* mMainDict = PyModule_GetDict( mMainModule );
   PyRun_String("import sys",Py_single_input, mMainDict, mMainDict );
// Next call work
   PyRun_String("from time import time, ctime\n",Py_single_input, mMainDict, mMainDict );
   PyRun_SimpleString("print ('Today is')");
   PyRun_String("print (ctime())",Py_single_input, mMainDict, mMainDict );

   PyRun_String("sys.path.append(\"D:/python/\")",Py_single_input, mMainDict, mMainDict );
   PyRun_String("import dlgFromPython",Py_single_input, mMainDict, mMainDict );
   //Call to fTestPrint() Work
   PyRun_String("dlgFromPython.fTestPrint()",Py_single_input, mMainDict, mMainDict );
   //Call to fOpenDlg() nothing happen
   PyRun_String("dlgFromPython.fOpenDlg()",Py_single_input, mMainDict, mMainDict );

  Py_Finalize();
}

Also when open a c++ dialog from my c++ QMainWindow
the reference to the QMainWindow is passed to the constructor of the dialog:

dlgVectorLayerColorScheme dlg(this);
dlg.exec();

How can do that in the python dialog
Also in necessary to create another QApplication in the python dialog?
Wich is the propper way to open a dialog from my c++ application

Greetings

[m.sue]

Hi,
when I use Python from within my C++ program I show the dialog from within the C++ program directly and afterwards provide the Python program with the contents of the dialog via pipe or config file.
-Michael.

[marceloarguello700]

@m.sue Thanks, but your answer is very short to my basic knowledge.
Some code sample will be more usefull for me.
Greeings

[SGaist]

Hi,

It seems you already know how to write a dialog with Qt.

What @m-sue suggested is that you rewrite your PyQt dialog in C++ and then pass whatever you want from the dialog as parameter to your python script.

[marceloarguello700]

@SGaist Thanks, now understand what @m.sue say, c++ is my prefered way to write dialogs, so i agree that passing parameters will be a more easy aproach.

But i only was analyzing and exploring how interact with python.

There is a gis sofware named QGIS that use many plugins writed in python,
with the respective dialogs also in Python. I read some of its code, but i
is complex and just want a few dialogs not a entire plugin management system.
Also in the web the examples of integration are very basics.

Greetings

[SGaist]

This stack overflow post might give you some additional information.

[marceloarguello700]

@SGaist Thanks, I will learn about PythonQt and see what happend.
Greetings