Qt中对于窗口边框的设置一般用到setWindowFlags函数。

void setWindowFlags(Qt::WindowFlags type)

如果只setWindowFlags(Qt::FramelessWindowHint);

去掉边框，此时会发现，当程序打开后，单击任务栏的按钮，会发现无法最小化，隐藏窗口。

解决的方法是：

setWindowFlags(Qt::Window|Qt::FramelessWindowHint |Qt::WindowSystemMenuHint|Qt::WindowMinimizeButtonHint|Qt::WindowMaximizeButtonHint);

再次测试，发现边框去掉了，而且鼠标点击任务栏图标，也可以显示和隐藏窗口了。

附：

Qt::Widget

This is the default type for QWidget.

Widgets of this type are child widgets if they have a parent,and independent(独立的) windows if they have no parent.

See also Qt::Window and Qt::SubWindow.

Qt::Window

Indicates（标志，象征） that the widget is a window.

Usually with a window system frame and a title bar,irrespective of (不管)whether the widget has a parent or not.

Note that it is not possible to unset this flag if the widget does not have a parent.

Qt::Dialog

Indicates that the widget is a window that should be decorated as a dialog (i.e., typically no maximize or minimize buttons in the title bar). This is the default type for QDialog. If you want to use it as a modal dialog, it should be launched from another window, or have a parent and used with the QWidget::windowModality property. If you make it modal, the dialog will prevent other top-level windows in the application from getting any input. We refer to a top-level window that has a parent as a secondary window.

Qt::FramelessWindowHint

Produces a borderless window.

The user cannot move or resize a borderless window via the window system.

On X11, the result of the flag is dependent on the window manager and its ability to understand Motif and/or NETWM hints. Most existing modern window managers can handle this.

Qt::CustomizeWindowHint

Turns off the default window title hints.

Qt::WindowTitleHint

Gives the window a title bar.

Qt::WindowSystemMenuHint

Adds a window system menu, and possibly a close button (for example on Mac).

 If you need to hide or show a close button, it is more portable to use WindowCloseButtonHint.

Qt::WindowMinimizeButtonHint

Adds a minimize button.

On some platforms this implies Qt::WindowSystemMenuHint for it to work.

Qt::WindowMaximizeButtonHint

Adds a maximize button.

On some platforms this implies Qt::WindowSystemMenuHint for it to work.

Qt::WindowMinMaxButtonsHint

Adds a minimize and a maximize button.

On some platforms this implies Qt::WindowSystemMenuHint for it to work.

Qt::WindowCloseButtonHint

Adds a close button.

 On some platforms this implies Qt::WindowSystemMenuHint for it to work.