On the Layout of pyqt5 in QMainWindow

Introduction:

If the parent class QMainWindow is used in pyqt5, the layout class, QGridLayout, QHBoxLayout, QVBoxLayout, is not useful in it.

Solve:

It is useful to use these three layout classes in a custom class that uses QWidget as its parent, but write a few more sentences when using QMainWindow.Specifically as follows:

widget = QWidget()
widget.setLayout(gridLayout)
self.setCentralWidget(widget)

Where do these sentences go?After your layout statement, where gridLayout refers to

gridLayout = QGridLayout(self)

With these words, it is used as in QWidget.