Catch the press event of the keystroke

1. Overwrite event filter.

    //.h file
    bool eventFilter(QObject* obj, QEvent* event) override;
   
    //.cpp file
    bool MainWindow::eventFilter(QObject* obj, QEvent* event)
    {
        if (event->type() == QEvent::KeyPress)
        {
            //force conversion
            QKeyEvent* keyEvent = static_cast<QKeyEvent*>(event);
   
            //eg. press T + Ctrl keys at the same time (pay attention to the type of different keys: key or modifiers)
            if (keyEvent->key() == Qt::Key_T && keyEvent->modifiers() == Qt::ControlModifier)
            {
                //special handle...
            }
            else
            {
                return QObject::eventFilter(obj, event);
            }
   
            return true;
        }
        else
            return QObject::eventFilter(obj, event);
    }
   

2. Install the event filter in the class constructor.

• Sometimes must install for qApp(not sure why)

qApp->installEventFilter(this);

Enable/disable the window to stay on top

The implementation code must be written in the constructor of the class, otherwise, it will have no effect.

Code as below:

//Enable
setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint);
//Disable
setWindowFlags(windowFlags() & ~Qt::WindowStaysOnTopHint);

show();  //sometimes need this code to be added at the end (not sure why)

NEXT...