PYQT Maya QMouseEvent won't work after I wrapInstance it

Question

from PySide2 import QtGui,QtCore,QtWidgets
from PySide2.QtGui import*
from PySide2.QtCore import *
from PySide2.QtWidgets import *
from shiboken2 import wrapInstance
import maya.OpenMayaUI as mui
import sys
class ui(QWidget):
    def __init__(self,parent):
        super(ui,self).__init__(parent)
        self.resize(300,500)
        self.mainWindow = QtWidgets.QMainWindow(parent)
        self.setupUI(self.mainWindow)
        self.setFocus()
    def setupUI(self,mainWindow):
        mymainWindow = QWidget(mainWindow)
        mymainWindow.resize(300,500)
    def mousePressEvent(self,e):
        print 'sdfasdf'
        if e.button()==Qt.RightButton:
            print "Clickkkk"
    def Show(self):
        self.mainWindow.show()
class app():
    def __init__(self):
        self.ptr = mui.MQtUtil.mainWindow()
        self.ptr = wrapInstance(long(self.ptr),QtWidgets.QWidget)      
        self.ui = ui(self.ptr)
    def runApp(self):
        self.ui.Show()
        self.ui.setFocus()

tt = app()
tt.runApp()

Here is the code I'm testing on. After using wrapInstance the mouseEvent are no longer working.

But if I didn't wrap it it's work

not working

class app():
    def __init__(self):
        self.ptr = mui.MQtUtil.mainWindow()
        self.ptr = wrapInstance(long(self.ptr),QtWidgets.QWidget)      
        self.ui = ui(self.ptr)
    def runApp(self):
        self.ui.Show()
        self.ui.setFocus()

working

I Also change some parent structure in UI class

class app():
    def __init__(self):    
        self.ui = ui()
    def runApp(self):
        self.ui.Show()

Can anyone explain why the MouseEvent won't work after I wrap it? And how to make it work?

Answer 1

The crux of the problem is this: self.ui.Show(). This runs your custom method, which in turn runs this self.mainWindow.show(). This causes self.mainWindow to show, but you subclassed mousePressEvent for ui, not self.mainWindow! So it's not running the event because you're clicking on the wrong widget.

Instead, since ui is a QWidget, call self.ui.show(). You may also have to put self.setWindowFlags(QtCore.Qt.Window) in ui's constructor. With this the mouse event runs as expected when the user clicks on it.

Some side notes:

I doubt that you actually want to create a QMainWindow in a QWidget. It just strikes as odd. Consider sub-classing a QMainWindow instead as it should be the 'top' widget.

Also try to avoid importing modules like from PySide2.QtCore import *, and import them like this instead from PySide2 import QtCore. It's bad practice, pollutes your module's scope, and makes the code much more unreadable/un-maintainable since it's hard to traceback where these variables come from.

Oh, and for the love of god, use some vertical white-spacing :)