Qt发送事件分为两种
-阻塞型事件发送
bool QApplication::sendEvent ( QObject * receiver, QEvent * event ) ;
// receiver:接收对象, event :要发送的event类型(比如:鼠标双击)
//当有事件发送,将会调用receiver对象里的event()成员函数进行事件处理
-非阻塞型事件发送
void QApplication::postEvent ( QObject * receiver, QEvent * event );
示例-通过sendEvent()发送预定义的键盘Delete按键事件
Wiget.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QtGui>
class Widget : public QWidget
{
Q_OBJECT
private :
QTextEdit edit;
QPushButton bt;
private slots:
void onPushButton();
public:
explicit Widget();
};
#endif // WIDGET_H
Widget.c
#include "widget.h"
Widget::Widget() : edit(this),bt("Delete",this)
{
edit.setGeometry(0,0,300,200);
bt.setGeometry(310,20,48,32);
connect(&bt, SIGNAL(clicked()), this, SLOT(onPushButton()));
}
void Widget::onPushButton()
{
int key = Qt::Key_Delete ;
QKeyEvent EventPress(QEvent::KeyPress,key,Qt::NoModifier);
QApplication::sendEvent(&edit,&EventPress); //发送键盘按下事件
QKeyEvent EventRelease(QEvent::KeyRelease,key,Qt::NoModifier);
QApplication::sendEvent(&edit,&EventRelease); //发送键盘松开事件
}
效果
自定义事件对象
class StringEvent : public QEvent
{
public:
static const Type = static_cast<Type>(QEvent::User+0x10);
explicit QStringEvent();
//... ...
}
QStringEvent::QStringEvent() :
QEvent(TYPE) //注册TYPE值
{
//... ...
}
常用两种方法来处理
1.通过事件过滤器处理
2.重写目标对象的event()函数
示例-通过单击鼠标按钮发送自定义事件QStringEvent
QStringEvent文件:
class QStringEvent : public QEvent
{
private:
QString mstr;
public:
const static Type TYPE = static_cast<Type>(QEvent::User+0x10);
explicit QStringEvent(QString s);
QString str();
};
QStringEvent::QStringEvent(QString s) :
QEvent(TYPE)
{
mstr = s;
}
QString QStringEvent::str()
{
return mstr;
}
widget文件:
class Widget : public QWidget
{
private :
QLabel label;
bool event( QEvent * e);
bool eventFilter(QObject *obj, QEvent *event);
public:
explicit Widget();
};
Widget::Widget() : label(this)
{
label.installEventFilter(this);
}
bool Widget::event( QEvent * e)
{
if(e->type() == QEvent::MouseButtonPress)
{
QMouseEvent *me = dynamic_cast<QMouseEvent* >(e);if(me->button() == Qt::LeftButton)
{
QStringEvent event( QString("X坐标: %1 Y坐标: %2").arg(me->x()).arg(me->y()) );
QApplication::sendEvent(&label,&event); //发送自定义事件
}
}
return QWidget::event(e);
}
bool Widget::eventFilter(QObject *obj, QEvent *event)
{
QLabel *t = dynamic_cast<QLabel* >(obj);
if(t && event->type()== QStringEvent::TYPE )
{
QStringEvent *str = dynamic_cast<QStringEvent* >(event);
t->setText(str->str());
t->adjustSize();
return true;
}
return QWidget::eventFilter(obj,event);
}
效果: