Qt学习笔记之图片的上下左右移动

Qt学习笔记之图片的上下左右移动

自己找的图片太大，在移动的时候不明显，懒得再找图片，所以用了QPainter将图片画在了label上
代码如下

void Widget::paintEvent(QPaintEvent *)
{QPainter painter(this);QPixmap pix;pix.load(":img/move.png");//图片的位置painter.drawPixmap(picLabel->x(),picLabel->y(),picLabel->width(),picLabel->height(),pix);
}

将图片上下左右移动是通过重写keyPressEvent虚方法，在这个方法中捕捉按钮事件，用move移动位置
代码如下
widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QLabel>
#include <QPainter>
#include <QKeyEvent>
#include <QDebug>class Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = 0);~Widget();
private:QLabel *picLabel;
protected:void paintEvent(QPaintEvent *);void keyPressEvent(QKeyEvent *event);void keyReleaseEvent(QKeyEvent *event);};#endif // WIDGET_H

widget.cpp

#include "widget.h"Widget::Widget(QWidget *parent): QWidget(parent)
{resize(500, 500);picLabel = new QLabel(this);picLabel->setFixedSize(50, 50);}
//将图片画在label
void Widget::paintEvent(QPaintEvent *)
{QPainter painter(this);QPixmap pix;pix.load(":img/move.png");//图片的位置painter.drawPixmap(picLabel->x(),picLabel->y(),picLabel->width(),picLabel->height(),pix);
}void Widget::keyPressEvent(QKeyEvent *event)
{int x = 0;int y = 0;switch (event->key()) {case Qt::Key_Up:y = picLabel->y() - 10;if(y > -10)picLabel->move(picLabel->x(), y);//向上移动就是x不变y减小break;case Qt::Key_Down:y = picLabel->y() + 10;if(y < this->height() - 40){picLabel->move(picLabel->x(), y);//向下移动是x不变y 变大}break;case Qt::Key_Right:x = picLabel->x() + 10;if(x < this->width() - 40){picLabel->move(x, picLabel->y());}break;case Qt::Key_Left:x = picLabel->x() - 10;if(x > -10)picLabel->move(x, picLabel->y());break;default:break;}
}void Widget::keyReleaseEvent(QKeyEvent *event)
{
}Widget::~Widget()
{}

main.cpp

#include "widget.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);Widget w;w.show();();
}

效果：