QLayout
sublcasses don't have a visual representation, which becomes clear by the fact that QLayout
classes do not inherit QWidget
. They only calculate the positions of the widgets they are responsible for in the context of their "parent" widget.
So the answer to questions 1,2 and 4 is basically: You can't.
You'll always have to have a QWidget
in combination with a QLayout
.
E.g. to group your two buttons into a frame with a box use a QFrame:
subLayoutC=QtGui.QVBoxLayout()
buttonFrame = QtGui.QFrame()
buttonFrame.setFrameStyle(QtGui.QFrame.Plain |QtGui.QFrame.Box)
buttonFrame.setLayout(subLayoutC)
subLayoutC.addWidget(QtGui.QPushButton('PushButton 1'))
subLayoutC.addWidget(QtGui.QPushButton('PushButton 2'))
# now we add the QFrame widget - not subLayoutC to the tabLayout
tabLayout.addWidget(buttonFrame) # I think your suggested edit was correct here
self.setCentralWidget(tabWidget)
Concerning question 3, check the docs:
http://qt-project.org/doc/qt-4.8/qlayout.html#setContentsMargins