QPainter提示Painter not active

[weixin_38054205]

我需要在一个Label上画图，连续画了很多张以后突然就画不出来了，提示QPainter::begin: Paint device returned engine == 0, type: 2QPainter::setPen: Painter not activeQPainter::begin: Paint device returned engine == 0, type: 2QPainter::setPen: Painter not active我是这样做的：    opix = new QPixmap(ui->label_25->size());    QPainter *oHisPainter = new QPainter(opix);    oHisPainter->fillRect(0,0,1861,361,Qt::white);    oHisPainter->setPen(QPen(QColor(0,0,0)));    oHisPainter->drawLine(18,321,1840,321);    oHisPainter->drawLine(1840,321,1835,316);    oHisPainter->drawLine(1840,321,1835,326);    oHisPainter->drawText(1842,321,tr("x"));网上看到有人说时堆栈溢出，不知道是这个原因么？该怎么解决呢？