QTouchEvent奇怪的行为

Question

该代码发生的事情是，当我想使用QGraphicsView :: event（）时，GameView :: event（）不会捕获QTouchEvent，但是当我不使用QGraphicsView :: event（）时一切正常。我想用这个父母 方法，因为我需要处理默认事件。

#include "gameview.h"
#include "QDebug"
#include <QGesture>
#include <QGestureEvent>
#include <QEvent>
#include <QTapGesture>
GameView::GameView(QWidget *parent):QGraphicsView (parent)
{
    this->setAttribute(Qt::WA_AcceptTouchEvents);
    setAttribute(Qt::WA_StaticContents);
    qDebug()<<"I am in GameView  constructor\n";
}

GameView::~GameView()
{
    qDebug()<<"I am in GameView deconstructor\n";
}

bool GameView::event(QEvent *event)
{
    switch (event->type()) {
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate:
    case QEvent::TouchEnd:
    {
        QList<QTouchEvent::TouchPoint> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();
        foreach (const QTouchEvent::TouchPoint &touchPoint, touchPoints)
        {
            switch (touchPoint.state())
            {
            case Qt::TouchPointStationary:
                // don't do anything if this touch point hasn't moved
                continue;
            case Qt::TouchPointPressed:
            {
                qDebug()<<"Touch Pressed";
                break;
            }
            case Qt::TouchPointReleased:
            {
                qDebug()<<"Touch Release";
                break;
            }
            default:
            {
                // qDebug()<<"Default";
                 break;
            }
                break;
            }
        }
        break;
    }
    default:
        return QGraphicsView::event(event);//if i comment that line then 
 //its works 
    }
    return true;
}