MousePressEvent is not getting in my Parent Widget



  • Hi,

    I have two customized widgets of which one acts as a parent and another as child.

    Parent inherits QScrollArea, and child inherits QWidget.

    I am not getting mousepressevent in my parent widget when i click the child widget. :(

    // child widget
    //table.h
    @#ifndef TABLE_H
    #define TABLE_H

    #include <QWidget>
    #include <QGridLayout>
    #include <QLabel>
    #include <QPoint>
    #include <QMouseEvent>

    class Table : public QWidget
    {
    Q_OBJECT
    public:
    explicit Table(QWidget *parent = 0);

    private:
    QString m_id,
    m_type,
    m_image,
    m_sectionId;
    QPoint m_position;
    int m_seatCount;

    QGridLayout *m_pMainLayout;
    QLabel      *m_pTableImage,
                *m_pBottomLabel,
                *m_pSeatImage;
    

    public:
    ...

    //protected:
    // void mousePressEvent(QMouseEvent *event);
    // void mouseReleaseEvent(QMouseEvent *event);
    // void mouseMoveEvent(QMouseEvent *event);
    // void mouseDoubleClickEvent(QMouseEvent *event);

    signals:

    public slots:

    };

    #endif // TABLE_H@

    // table.cpp
    @#include "table.h"
    #include <QDebug>
    #include <QApplication>

    Table::Table(QWidget *parent) :
    QWidget(parent),
    m_seatCount(0)
    {
    qDebug() << Q_FUNC_INFO << "Invoked";

    m_pMainLayout   = new QGridLayout(this);
    m_pTableImage   = new QLabel(this);
    m_pBottomLabel  = new QLabel(this);
    m_pSeatImage    = new QLabel(this);
    
    if (NULL != m_pMainLayout && NULL != m_pTableImage &&
        NULL != m_pBottomLabel  && NULL != m_pSeatImage)
    {
        setLayout(m_pMainLayout);
        m_pMainLayout->addWidget(m_pTableImage, 0, 0, 2, 2);
        m_pMainLayout->addWidget(m_pBottomLabel, 2, 0);
        m_pMainLayout->addWidget(m_pSeatImage, 2, 1);
    
        m_pTableImage->setObjectName("tableImage");
        m_pBottomLabel->setObjectName("bottomLabel");
        m_pSeatImage->setObjectName("seatImage");
    }
    
    qDebug() << Q_FUNC_INFO << "Exits";
    

    }
    @

    //Parent widget
    //hearderfile
    @#ifndef TABLESOURCESCROLLAREA_H
    #define TABLESOURCESCROLLAREA_H

    #include <QScrollArea>
    #include <QVBoxLayout>
    #include <QMouseEvent>
    #include <QDataStream>
    #include <QMimeData>
    #include <QPoint>
    #include <QDrag>

    #include "tablesourcewidget.h"
    #include "table.h"

    class TableSourceScrollArea : public QScrollArea
    {
    Q_OBJECT
    public:
    explicit TableSourceScrollArea(QWidget *parent = 0);

    private:

    void createDislpay();
    
    //TableSourceWidget   *m_pTableSourceWidget;
    QVBoxLayout         *m_pMainVLayout;
    
    
    Table   *m_pSquareTable,
            *m_pCircleTable,
            *m_pOvalTable,
            *m_pRectangleTable;
    

    protected:
    void mousePressEvent(QMouseEvent *event);

    signals:

    public slots:

    };

    #endif // TABLESOURCESCROLLAREA_H
    @

    // source file
    @#include "tablesourcescrollarea.h"
    #include <QDebug>

    TableSourceScrollArea::TableSourceScrollArea(QWidget *parent) :
    QScrollArea(parent)
    {
    createDislpay();
    }

    void TableSourceScrollArea::createDislpay()
    {
    qDebug() << Q_FUNC_INFO << "Invoked";

    m_pMainVLayout      = new QVBoxLayout(this);
    
    m_pSquareTable      = new Table(this);
    m_pCircleTable      = new Table(this);
    m_pOvalTable        = new Table(this);
    m_pRectangleTable   = new Table(this);
    
    if (NULL != m_pSquareTable  && NULL != m_pCircleTable &&
        NULL != m_pOvalTable    && NULL != m_pRectangleTable &&
        NULL != m_pMainVLayout)
    {
        setLayout(m_pMainVLayout);
        // source tables
        m_pMainVLayout->addWidget(m_pSquareTable);
        m_pMainVLayout->addWidget(m_pCircleTable);
        m_pMainVLayout->addWidget(m_pOvalTable);
        m_pMainVLayout->addWidget(m_pRectangleTable);
    

    ...
    }

    qDebug() << Q_FUNC_INFO << "Exits";
    

    }

    void TableSourceScrollArea::mousePressEvent(QMouseEvent *event)
    {
    qDebug() << Q_FUNC_INFO << "Invoked";

    Table *table = static_cast<Table*>(childAt(event->pos()));
    if (!table)
    {
        qDebug() << Q_FUNC_INFO << "Exit NULL Param";
        return;
    }
    
    ...
    qDebug() << Q_FUNC_INFO << "Exits";
    

    }
    @

    as read from article : "mouse event propagation":http://blog.qt.digia.com/blog/2006/05/27/mouse-event-propagation/

    I get to know if child widget doesn't implement event handlers it will be pass to parent widget. But my parent widget handler is not getting is not getting invoked when i click on child.
    Can someone tell where am I going wrong?



  • Where are you setting the parent and child relation ship ? Did you check whether event is really received by the child widget ? You can just implement mousePress in child and see. I feel either parent->child relationship is not correct or event is consumed by some other widget.



  • The Scroll ares itself does not accept the events, rather the scroll area's viewport accepts those events. Rather than subclassing the scroll area to create the event handler, install the event handler on the scroll area's viewport().

    Here is a decent article on this issue

    http://www.setnode.com/blog/mouse-wheel-events-event-filters-and-qscrollarea/



  • @ dvb0222

    Thanks. For time being I've changed my parent widget inheriting from QWidget and it works :)

    Ill try using viewport() and will update.


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