跟着网上的教程学的，自己又加上了一些。这是一个继承了QLabel的类。
当我仅添加paintEvent的时候，正常运行。
当我仅添加mouseMoveEvent、mousePressEvent、mouseReleaseEvent的时候，同样正常运行（即label上会随着鼠标的状态显示不同的文字）。
但是当这四个事件同时存在的时候，鼠标的事件就不起作用了。可能是event之间互相影响导致的？
求指教。谢谢！
#include <QApplication>
#include <QWidget>
#include <QLabel>
#include <QMouseEvent>
#include <QPainter>
class EventLabel : public QLabel
{
protected:
void mouseMoveEvent(QMouseEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent *event);
void paintEvent(QPaintEvent *event);
};
void EventLabel::paintEvent(QPaintEvent *event)
{
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, true);
QLinearGradient linearGradient(60, 50, 200, 200);
linearGradient.setColorAt(0.2, Qt::white);
linearGradient.setColorAt(0.6, Qt::green);
linearGradient.setColorAt(1.0, Qt::black);
painter.setBrush(QBrush(linearGradient));
painter.drawEllipse(50, 50, 200, 150);
}
void EventLabel::mouseMoveEvent(QMouseEvent *event)
{
this->setText(QString("<center><h1>Move: (%1, %2)</h1></center>")
.arg(QString::number(event->x()), QString::number(event->y())));
}
void EventLabel::mousePressEvent(QMouseEvent *event)
{
this->setText(QString("<center><h1>Press: (%1, %2)</h1></center>")
.arg(QString::number(event->x()), QString::number(event->y())));
}
void EventLabel::mouseReleaseEvent(QMouseEvent *event)
{
QString msg;
msg.sprintf("<center><h1>Release: (%d, %d)</h1></center>",
event->x(), event->y());
this->setText(msg);
}
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
EventLabel *label = new EventLabel;
label->setWindowTitle("MouseEvent Demo");
label->resize(300, 200);
label->show();
return app.exec();
}
