Qt事件Event

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我是靠谱客的博主成就冰淇淋，最近开发中收集的这篇文章主要介绍Qt事件Event，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

Qt事件Event
1.事件函数event
2.鼠标事件
3.键盘事件
4.窗口大小变化事件
5.重绘事件

重载event


1.bool event(QEvent *e);
2.返回true 处理下一个事件
3.返回false本事件的下一个处理函数

QEvent子类

1.QKeyEvent,QMouseEvent
2.QTouchEvent,QWheelEvent

QWidget重载函数


1.virtual void keyPressEvent(QKeyEvent *event);
2.virtual void keyReleaseEvent(QKeyEvent *event);
3.virtual void leaveEvent(QEvent* event);
4.virtual void mouseDoubleClickEvent(QMouseEvent *event);
5.virtual void mouseMoveEvent(QMouseEvent *Event);
6.virtual void mousePressEvent(QMouseEvent *Event);
7.virtual void mouseReleaseEvent(QMouseEvent *Event);
8.virtual void moveEvent(QMoveEvent *event);
9.virtual void resizeEvent(QResizeEvent *event);
10.virtual void showEvent(QShowEvent *event);
11.virtual void wheelEvent(QWheelEvent *event);
12.virtual void paintEvent(QPaintEvent *event);

QMouseEvent坐标
1.x() y() 相对（本地）坐标
2.QPoint windowPos() 程序窗口坐标
3.screenPos() 屏幕坐标
4.QWidget::mapToGlobal(ev->pos()); 屏幕
5.QCursor::pos()屏幕

QMouseEvent按键状态
1.buttons() & Qt::LeftButton
2.Qt::RightButton Qt::MidButton
3.(me->buttons() & Qt::LeftButton)
&&(me->buttons() & Qt::RightButton)

鼠标事件函数的重载


1.virtual void enterEvent(QEvent *event);
2.virtual void leaveEvent(QEvent *event);
3.virtual void mouseDoubleClickEvent(QMouseEvent *event);
4.virtual void mouseMoveEvent(QMouseEvent *event);
5.virtual void mousePressEvent(QMouseEvent *event);
6.virtual void mouseReleaseEvent(QMouseEvent *event);

xlabel.cpp


#include "xlabel.h"
#include <QDebug>
#include <QMouseEvent>

XLabel::XLabel(QWidget* parent)
    : QLabel(parent)
{
}

XLabel::~XLabel()
{

}


bool XLabel::event(QEvent *ev)
{
    if(ev->type() == QEvent::MouseButtonPress)
    {
        QMouseEvent *me = static_cast<QMouseEvent*> (ev);
        //相对坐标
        qDebug()<<"LocalPos "<<me->x()<<":"<<me->y();
        //程序坐标
        qDebug()<<"windowPos "<<me->windowPos().x()<<":"<<me->windowPos().y();
        //屏幕坐标
        qDebug()<<"windowPos "<<me->screenPos().x()<<":"<<me->screenPos().y();
        //本地坐标转全局坐标
        QPoint gpos =  mapToGlobal(me->pos());
        qDebug()<<"mapToGlobal "<<gpos.x()<<":"<<gpos.y();
        
        //获取鼠标屏幕坐标
        qDebug()<<"QCursor "<<QCursor::pos().x()<<":"<<QCursor::pos().y();
    
        //鼠标按键事件
        if(me->buttons() & Qt::LeftButton)
        {
            qDebug()<<"LeftButton";
        }
        if(me->buttons() & Qt::RightButton)
        {
            qDebug()<<"RightButton";
        }
        if(me->buttons() & Qt::MiddleButton)
        {
            qDebug()<<"MidButton";
        }
        //左右同时按下
        if((me->buttons() & Qt::LeftButton) && (me->buttons() & Qt::RightButton))
        {
            qDebug()<<"LeftButton and RightButton";
        }
    }

    return QWidget::event(ev);
}

光标的样式


QCursor cursor;
QPixmap pixmap("cursor.png");
//-1,-1表示热点取中间
cursor = QCursor(pixmap,-1,-1);
setCursor(cursor);

setCursor(Qt::ArrowCursor);

xlabel.cpp


#include "xlabel.h"
#include <QDebug>
#include <QMouseEvent>

XLabel::XLabel(QWidget* parent)
    : QLabel(parent)
{
    setMouseTracking(true);
}

XLabel::~XLabel()
{

}


bool XLabel::event(QEvent *ev)
{
    if(ev->type() == QEvent::MouseButtonPress)
    {
        QMouseEvent *me = static_cast<QMouseEvent*> (ev);
        //相对坐标
        qDebug()<<"LocalPos "<<me->x()<<":"<<me->y();
        //程序坐标
        qDebug()<<"windowPos "<<me->windowPos().x()<<":"<<me->windowPos().y();
        //屏幕坐标
        qDebug()<<"windowPos "<<me->screenPos().x()<<":"<<me->screenPos().y();
        //本地坐标转全局坐标
        QPoint gpos =  mapToGlobal(me->pos());
        qDebug()<<"mapToGlobal "<<gpos.x()<<":"<<gpos.y();
        
        //获取鼠标屏幕坐标
        qDebug()<<"QCursor "<<QCursor::pos().x()<<":"<<QCursor::pos().y();
    
        //鼠标按键事件
        if(me->buttons() & Qt::LeftButton)
        {
            qDebug()<<"LeftButton";
            setCursor(Qt::ArrowCursor);
        }
        if(me->buttons() & Qt::RightButton)
        {
            qDebug()<<"RightButton";
        }
        if(me->buttons() & Qt::MiddleButton)
        {
            qDebug()<<"MidButton";
        }
        //左右同时按下
        if((me->buttons() & Qt::LeftButton) && (me->buttons() & Qt::RightButton))
        {
            qDebug()<<"LeftButton and RightButton";
            //鼠标图标替换
            QPixmap pix("vline.png");
            QCursor cur = QCursor(pix,-1,-1);
            setCursor(cur);
        }
    }
    return QWidget::event(ev);
}

ui_widget.h


#ifndef UI_WIDGET_H
#define UI_WIDGET_H

#include <QtCore/QVariant>
#include <QtWidgets/QApplication>
#include <QtWidgets/QWidget>
#include "xlabel.h"

QT_BEGIN_NAMESPACE

class Ui_Widget
{
public:
    XLabel *label;

    void setupUi(QWidget *Widget)
    {
        if (Widget->objectName().isEmpty())
            Widget->setObjectName(QString::fromUtf8("Widget"));
        Widget->resize(800, 600);
        label = new XLabel(Widget);
        label->setObjectName(QString::fromUtf8("label"));
        label->setGeometry(QRect(200, 200, 400, 400));
        label->setStyleSheet(QString::fromUtf8("background-color: rgb(92, 53, 102);"));

        retranslateUi(Widget);

        QMetaObject::connectSlotsByName(Widget);
    } // setupUi

    void retranslateUi(QWidget *Widget)
    {
        Widget->setWindowTitle(QCoreApplication::translate("Widget", "Widget", nullptr));
        label->setText(QString());
    } // retranslateUi

};

namespace Ui {
    class Widget: public Ui_Widget {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_WIDGET_H

窗口大小改变事件


void resizeEvent(QResizeEvent *event);
if(ev->type() == QEvent::Resize)
const QSize &oldSize() const;
const QSize &size() const;

ui_widget.h


#ifndef UI_WIDGET_H
#define UI_WIDGET_H

#include <QtCore/QVariant>
#include <QtWidgets/QApplication>
#include <QtWidgets/QLabel>
#include <QtWidgets/QWidget>

QT_BEGIN_NAMESPACE

class Ui_Widget
{
public:
    QLabel *label;

    void setupUi(QWidget *Widget)
    {
        if (Widget->objectName().isEmpty())
            Widget->setObjectName(QString::fromUtf8("Widget"));
        Widget->resize(800, 600);
        label = new QLabel(Widget);
        label->setObjectName(QString::fromUtf8("label"));
        label->setGeometry(QRect(0, 30, 800, 670));
        label->setStyleSheet(QString::fromUtf8("background-color: rgb(92, 53, 102);"));

        retranslateUi(Widget);

        QMetaObject::connectSlotsByName(Widget);
    } // setupUi

    void retranslateUi(QWidget *Widget)
    {
        Widget->setWindowTitle(QCoreApplication::translate("Widget", "Widget", nullptr));
        label->setText(QString());
    } // retranslateUi

};

namespace Ui {
    class Widget: public Ui_Widget {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_WIDGET_H

widget.cpp


#include "widget.h"
#include "ui_widget.h"
#include <QResizeEvent>

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
}

bool Widget::event(QEvent *e)
{
    if(e->type() == QEvent::Resize)
    {
        QResizeEvent *re = static_cast<QResizeEvent *>(e);
        qDebug()<<"Resize old "<<re->oldSize().width()<<":"<<re->oldSize().height();
        qDebug()<<"new size"<<re->size().width()<<":"<<re->size().height();
    }
    return QWidget::event(e);
}

Widget::~Widget()
{
    delete ui;
}