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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#include class Widget : public QWidget{ Q_OBJECTprivate : 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 (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 (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 (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 (obj); if(t && event->type()== QStringEvent::TYPE ) { QStringEvent *str = dynamic_cast (event); t->setText(str->str()); t->adjustSize(); return true; } return QWidget::eventFilter(obj,event);} 效果:
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