centralWidget always in center

[xyfix]

Can somebody tell me how I can position the centralwidget in the center of the mainwindow. I have a QTextEdit as a centralWidget and I want it always to be in the middle of the window.

[wysota]

You probably forgot to apply a layout to your central widget (which is probably the parent of the text edit).

[xyfix]

Can you tell me how many layout objects I need, since I want the central widget(size of a A4 or Letter) always to be placed in the center of the main window and thus nothing on the left or right. Should I add a layout to the central widget and then three other widgets (left, middle, right) with three seperate layouts coupled to them? or is one central widget layout enough.

[wysota]

Can you tell me how many layout objects I need
Just one...