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