qt窗口置顶

设置Qt::WindowStaysOnTopHint

 this->setWindowFlags(Qt::Tool| Qt::FramelessWindowHint|Qt::WindowStaysOnTopHint|Qt::X11BypassWindowManagerHint);

Qt::WindowStaysOnTopHint帮助文档

Informs the window system that the window should stay on top of all other windows. Note that on some window managers on X11 you also have to pass Qt::X11BypassWindowManagerHint for this flag to work correctly.

windows下

如果不是第一时间启动，还需在类构造函数设置

#ifdef Q_OS_WIN32
    ::SetWindowPos(HWND(this->winId()), HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_SHOWWINDOW);
#endif

唤醒

#ifdef Q_OS_WIN32
    ::SetWindowPos(HWND(this->winId()), HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_SHOWWINDOW);
#endif
    this->show();
    this->setWindowState(this->windowState() & ~Qt::WindowMinimized);
    this->raise();
    this->activateWindow();