void QWidget::setWindowState ( Qt::WindowStateswindowState )
这样的函数,通过它可以设置窗体的初始状态,Qt::WindowStates 一共有下面几种状态:

Constant Value Description
Qt::WindowNoState 0x00000000 The window has no state set (in normal state).
Qt::WindowMinimized 0x00000001 The window is minimized (i.e. iconified).
Qt::WindowMaximized 0x00000002 The window is maximized with a frame around it.
Qt::WindowFullScreen 0x00000004 The window fills the entire screen without any frame around it.
Qt::WindowActive 0x00000008 The window is the active window, i.e. it has keyboard focus.
有了这个就非常easy 了,想让窗体最大化,只需要

setWindowState(Qt::WindowMaximized);就行了