How to detect if a Qt GUI application has been idle, inside the app itself (Qt)?

qt

Solution

Override QCoreApplication::notify and a timer on mouse/keyboard events?

(Or just store the time of the event and have a timer check that value periodically, which might be faster than resetting a timer all the time.)

class QMyApplication : public QApplication
{
public:
    QTimer m_timer;

    QMyApplication() {
        m_timer.setInterval(5000);
        connect(&m_timer, SIGNAL(timeout()), this, SLOT(app_idle_for_five_secs());
        m_timer.start();
    }
slots:
    bool app_idle_for_five_secs() {
        m_timer.stop();
        // ...
    }
protected:
    bool QMyApplication::notify ( QObject * receiver, QEvent * event )
    {
        if (event->type == QEvent::MouseMove || event->type == QEvent::KeyPress) {
             m_timer.stop(); // reset timer
             m_timer.start();
        }    
        return QApplicaiton::notify(receiver, event);
    }
};

Problem

How to detect when a GUI application has been idle, (ie, no user interaction), for a period of time ? I have n number of Qt Screens , I want to bring Date-Time screen when application is idle for 5 seconds and when i click on Date-Time screen it should return back to the last screen. Currently I am using below code, now how to check if system is idle for 5 seconds bring a new form and when some body mousemove/click it should go back to the last form. ``` CustomEventFilter::CustomEventFilter(QObject *parent) : QObject(parent) { m_timer.setInterval(5000); connect(&m_timer,SIGNAL(timeout()),this,SLOT(ResetTimer())); } bool CustomEventFilter::eventFilter(QObject *obj, QEvent *ev) { if(ev->type() == QEvent::KeyPress || ev->type() == QEvent::MouseMove) { ResetTimer(); return QObject::eventFilter(obj, ev); } else { } } bool CustomEventFilter::ResetTimer() { m_timer.stop(); // reset timer } ``` And my main.cpp looks like this : ``` int main(int argc, char *argv[]) { QApplication a(argc, argv); MainForm w; w.show(); CustomEventFilter filter; a.installEventFilter(&filter); return a.exec(); } ``` Thanks.

Original source