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); } 1234567 1234567

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_OBJECT public: Widget(QWidget *parent = 0); ~Widget(); private: QLabel *picLabel; protected: void paintEvent(QPaintEvent *); void keyPressEvent(QKeyEvent *event); void keyReleaseEvent(QKeyEvent *event); }; #endif // WIDGET_H 123456789101112131415161718192021222324252627 123456789101112131415161718192021222324252627

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() { } 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263

main.cpp

#include "widget.h" #include <QApplication> int main(int argc, char *argv[]) { QApplication a(argc, argv); Widget w; w.show(); return a.exec(); } 1234567891011 1234567891011

效果：