Long Press Event in Qt

I just want to know if there is a long press event available in Qt

The module im working on currently requires long press. I have seen long press in C7 for uninstalling.

The but开发者_开发知识库ton click event and the button press event gives the same result right?

alfah

You can have a look at Qt's gesture framework,
The gesture you are after would be QTapAndHoldGesture then I think.

You can use

keyPressEvent ( QKeyEvent * event )

and

keyReleaseEvent ( QKeyEvent * event )

for handle long_press_event

The quick, easy and old fashioned way, if you don't want to use that gesture stuff goes a little something like this:

In header declare a millisecond time stamp to hold the time of last press.

private:
    // Remembers the point in time when mouse button went down
    quint64 mLastPressTime=0;
    // Pressing and holding for one full second constitutes a "longpress", set whatever value in milliseconds you want here.
    static const quint64 MY_LONG_PRESS_THRESHOLD=1000; 
protected:
    // Declare that we are overriding QWidget's events for mouse press and release
    void mousePressEvent(QMouseEvent *) Q_DECL_OVERRIDE;
    void mouseReleaseEvent(QMouseEvent *) Q_DECL_OVERRIDE;
signals:
    // Our custom signal to emit once a longpress is detected.
    void longPressEvent(QMouseEvent *);

In source define the mouse press and release handlers like so:

void MyClass::mousePressEvent(QMouseEvent *event)
{
    // Remeber last time mousr was pressed
    mLastPressTime=QDateTime::currentMSecsSinceEpoch();
}

void MyClass::mouseReleaseEvent(QMouseEvent *event)
{
    // Calculate for how long the button has been pressed upon release
    const quint64 pressTime = QDateTime::currentMSecsSinceEpoch() - mLastPressTime;
    // The press time exceeds our "threshold" and this constitutes a longpress
    if( pressTime > MY_LONG_PRESS_THRESHOLD){
        // We pass the original mouse event in case it is useful (it contains all sorts of goodies like mouse posittion, which button was pressed etc).
        emit longPressEvent(event);
    }
}

NOTE: I did not compile this code, except in the built in compiler in my head which has a lot of non-traditional extensions.