QT 中paintEvent的问题

显示全部楼层 · 2021-1-27 05:08:48

想要利用QT画一个雷达图，编写了如下的程序：
voidRadarDlg::paintEvent(QPaintEvent*)
{
QPainter*painter=newQPainter(this);
painter->setRenderHint(QPainter::Antialiasing);
painter->setRenderHint(QPainter::SmoothPixmapTransform);
painter->setRenderHint(QPainter::TextAntialiasing);
drawRadarType(painter);
drawLabel(painter);
drawData(painter);
drawAxisLabel(painter);
}
但是运行时，会报警告：
QBackingStore::endPaint()calledwithactivepainteronbackingstorepaintdevice
QPaintDevice:Cannotdestroypaintdevicethatisbeingpainted
然后给paintEvent加上begin()和end()
voidCRadarDlg::paintEvent(QPaintEvent*)
{
QPainter*painter=newQPainter(this);
painter->begin(this);
painter->setRenderHint(QPainter::Antialiasing);
painter->setRenderHint(QPainter::SmoothPixmapTransform);
painter->setRenderHint(QPainter::TextAntialiasing);
drawRadarType(painter);
drawLabel(painter);
drawData(painter);
drawAxisLabel(painter);
painter->end();
}
还是有警告：
QPainter::begin:Painteralreadyactive
请问该如何让解决？
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千问 · 2021-1-27 05:08:48

试一下deletepainter；painter=NULL；

千问 · 2021-1-27 05:08:48

引用1楼这是一个正经昵称的回复:试一下deletepainter；painter=NULL；
试了一下，还是不行。

千问 · 2021-1-27 05:08:48

引用2楼qq_41621832的回复:Quote: 引用1楼这是一个正经昵称的回复:
试一下deletepainter；painter=NULL；
试了一下，还是不行。
QPainter*p=newQPainter;
p->begin(this);
p->setBrush(QBrush(QColor(222,222,123)));
p->drawRect(0,0,10,20);
p->end();
deletep;
p=NULL;

千问 · 2021-1-27 05:08:48

这个不管用呀？楼主最后怎么解决的呢？求赐教。