Qt获取当前屏幕大小

1、头文件

#include<QScreen>

　

2、代码

QScreen *screen = QGuiApplication::primaryScreen ();
QRect screenRect =  screen->availableVirtualGeometry();

resize(screenRect.width(),screenRect.height());

3、如果想直接初始主窗口最大化

setWindowState(Qt::WindowMaximized);

4、下面这些参数可用设定主窗口初始状态

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.