PyQt - Manually resizing menu widget does not resize its content

Question

I am using a QToolButton to open up a menu, which is a simple QWidget. Inside this widget live a QTextEdit and a Button. At the lower right corner there is a QSizeGrip which I w

Answer 1

Problem is because Button.menu doesn't inform your widget about size change.

In ToolBar you can assign own function to resizeEvent which will resize your widget.

You need access to your widget

    self.MyW = MyWidget()

and you can assign own function

    self.Button.menu().resizeEvent = self.onResize

def onResize(self, event):        
    self.MyW.resize(event.size())

Full code:

import sys
from PyQt4 import QtGui, QtCore

class MyWidget(QtGui.QWidget):

    def __init__(self, parent=None):
        super(MyWidget, self).__init__(parent)    
        self.setLayout(QtGui.QVBoxLayout())

        self.TextEdit = QtGui.QTextEdit()

        self.Button = QtGui.QPushButton("Push")

        self.UpdateWidget = QtGui.QWidget()
        self.UpdateWidget.setLayout(QtGui.QHBoxLayout())
        self.UpdateWidget.layout().addWidget(self.Button, 1)
        self.UpdateWidget.layout().addWidget(QtGui.QSizeGrip(self), 0)

        self.layout().addWidget(self.TextEdit)
        self.layout().addWidget(self.UpdateWidget)

        self.layout().setSpacing(0)
        self.layout().setContentsMargins(0,0,0,0)
        self.UpdateWidget.layout().setSpacing(4)
        self.UpdateWidget.layout().setContentsMargins(0,0,0,0)


class ToolBar(QtGui.QWidget):

    def __init__(self, parent=None):
        super(ToolBar, self).__init__(parent)
        self.setLayout(QtGui.QHBoxLayout())

        self.Button = QtGui.QToolButton()
        self.Button.setText("Open Text Editor")
        self.Button.setPopupMode(QtGui.QToolButton.InstantPopup)
        self.Button.setMenu(QtGui.QMenu(self.Button))

        self.MyW = MyWidget() # <-- here
        action = QtGui.QWidgetAction(self.Button) 
        action.setDefaultWidget(self.MyW) # <-- here

        self.Button.menu().addAction(action)
        self.layout().addWidget(self.Button)

        self.Button.menu().resizeEvent = self.onResize # <-- here

    def onResize(self, event):        # <-- here
        self.MyW.resize(event.size()) # <-- here

class App(QtGui.QMainWindow):

    def __init__(self, parent=None):
        super(App, self).__init__(parent)

        #Option 1: 
        #Use MyWidget in MainWindow. This works as expected.
        #self.central = MyWidget()

        #Option 2:
        #Use MyWidget as default widgt for a menu action. 
        #In this case MyWidget cannot be resized.
        self.central = ToolBar()

        self.setCentralWidget(self.central)


if __name__=='__main__':
    app = QtGui.QApplication(sys.argv)
    thisapp = App()
    thisapp.show()
    sys.exit(app.exec_())

---

Maybe it can be done olny with SizeGrip and MyWidget but I didn't try