#ifndef _STRINGEVENT_H_
#define _STRINGEVENT_H_

#include <QEvent>
#include <QString>

//自定义事件类必须继承自QEvent
class StringEvent : public QEvent
{
    QString m_data;
public:

    //必须提供事件类的Type值
    static const Type TYPE = static_cast<Type>(QEvent::User + 0xFF);

    explicit StringEvent(QString data = "");
    QString data();
};

#endif // _STRINGEVENT_H_

#include "StringEvent.h"

StringEvent::StringEvent(QString data):QEvent(TYPE)
{
    m_data = data;
}

QString StringEvent::data()
{
    return m_data;
}

#ifndef WIDGET_H
#define WIDGET_H

#include <QtGui/QWidget>
#include <QPushButton>
#include <QLineEdit>


class Widget : public QWidget
{
    Q_OBJECT

    QLineEdit myLineEdit;
    QPushButton myButton;

public:
    bool eventFilter(QObject *obj, QEvent *evt);
    Widget(QWidget *parent = 0);
    bool event(QEvent* e);

    ~Widget();
};

#endif // WIDGET_H

#include "Widget.h"
#include "StringEvent.h"
#include <QApplication>
#include <QMouseEvent>
#include <qDebug>

Widget::Widget(QWidget *parent)
    : QWidget(parent),myLineEdit(this)
{
    myLineEdit.installEventFilter(this);//this 对象作为过滤器来检测myLineEdit对象收到的事件
}

//发送自定义事件对象（当鼠标双击窗口时）。
bool Widget::event(QEvent* evt)
{
    if(evt->type() == QMouseEvent::MouseButtonDblClick)
    {
        qDebug() << "event: Before sentEvent";

        StringEvent se("SantaClaus"); 

        QApplication::sendEvent(&myLineEdit, &se);//将事件对象发送给编辑框

        qDebug() << "event: After sendEvent";

    }
    return QWidget::event(evt);
}

//自定义事件的处理，通过eventFilter编写自定义事件的处理逻辑
bool Widget::eventFilter(QObject *obj, QEvent *evt)
{
    if((obj == &myLineEdit) && (evt->type() == StringEvent::TYPE))
    {
        StringEvent* se = dynamic_cast<StringEvent*>(evt);

        myLineEdit.insert(se->data());

        qDebug() <<"Receive: " << se->data();

        return true;
    }

    return QWidget::eventFilter(obj, evt);
}


Widget::~Widget()
{

}

#include <QtGui/QApplication>
#include "Widget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    
    return a.exec();
}