事件mousePressEvent、paintEvent、closeEvent、keyPressEvent】

事件 mousePressEvent、paintEvent、closeEvent、keyPressEvent

鼠标样式的设置

按WSAD通过keyPressEvent事件移动按钮

通过事件mousePressEvent获取鼠标位置的相对位置，绝对位置

cusor 鼠标样式设置成十字星

.h

#ifndef DEFAULTHANDLEREXAMPLE_H
#define DEFAULTHANDLEREXAMPLE_H#include <QWidget>
#include <QPaintEvent>namespace Ui {
class DefaultHandlerExample;
}class DefaultHandlerExample : public QWidget
{Q_OBJECT
protected:void paintEvent(QPaintEvent *event);void closeEvent(QCloseEvent *event);void keyPressEvent(QKeyEvent *event);void showEvent(QShowEvent *event);void hideEvent(QHideEvent *event);void mousePressEvent(QMouseEvent *event);public:explicit DefaultHandlerExample(QWidget *parent = nullptr);~DefaultHandlerExample();private:Ui::DefaultHandlerExample *ui;
};#endif // DEFAULTHANDLEREXAMPLE_H

.cpp

#include "defaulthandlerexample.h"
#include "ui_defaulthandlerexample.h"#include <QMessageBox>
#include <QPainter>DefaultHandlerExample::DefaultHandlerExample(QWidget *parent): QWidget(parent), ui(new Ui::DefaultHandlerExample)
{ui->setupUi(this);this->setMouseTracking(false);//只有按下鼠标才会跟踪
}DefaultHandlerExample::~DefaultHandlerExample()
{delete ui;
}
void DefaultHandlerExample::paintEvent(QPaintEvent *event)
{Q_UNUSED(event);QPainter painter(this);painter.drawPixmap(0,0,this->width(),this->height(),QPixmap(":/toolbar/images/background.jpg"));
}void DefaultHandlerExample::closeEvent(QCloseEvent *event)
{QString dlgTitle ="提示";QString strInfo ="确定要退出吗?";QMessageBox::StandardButton result=QMessageBox::question(this,dlgTitle,strInfo,QMessageBox::Yes|QMessageBox::No|QMessageBox::Cancel);if(result== QMessageBox::Yes)event->accept();//窗口确认关闭elseevent->ignore();//忽略
}void DefaultHandlerExample::keyPressEvent(QKeyEvent *event)
{QPoint pt = ui->btnMove->pos();if((event->key()== Qt::Key_A)|| (event->key()==Qt::Key_Left))ui->btnMove->move(pt.x()-20,pt.y());if((event->key()== Qt::Key_D)|| (event->key()==Qt::Key_Right))ui->btnMove->move(pt.x()+20,pt.y());if((event->key()== Qt::Key_W)|| (event->key()==Qt::Key_Up))ui->btnMove->move(pt.x(),pt.y()-20);if((event->key()== Qt::Key_S)|| (event->key()==Qt::Key_Down))ui->btnMove->move(pt.x(),pt.y()+20);// this->setWindowTitle(event->ke);
}void DefaultHandlerExample::showEvent(QShowEvent *event)
{Q_UNUSED(event);ui->label->setText("showEvent函数被触发");
}void DefaultHandlerExample::hideEvent(QHideEvent *event)
{Q_UNUSED(event);ui->label->setText("hideEvent函数被触发");
}void DefaultHandlerExample::mousePressEvent(QMouseEvent *event)
{if(event->button()==Qt::LeftButton){QPoint pt = event->pos(); //窗口上的相对坐标QPointF relaPt = event->position(); //相对坐标QPointF winPt = event->scenePosition();//相对坐标QPointF globalPt = event->globalPosition();//屏幕上的绝对坐标QString str = QString::asprintf("pos()=(%d,%d)",pt.x(),pt.y());str+= QString::asprintf("\nposition()=%.0f,%.0f",relaPt.x(),relaPt.y());str+= QString::asprintf("\nscenePosition()=%.0f,%.0f",winPt.x(),winPt.y());str+= QString::asprintf("\nglobalPosition()=%.0f,%.0f",globalPt.x(),globalPt.y());ui->label->setText(str);ui->label->adjustSize();ui->label->move(event->pos());//标签移动到鼠标光标处}QWidget::mousePressEvent(event);
}