Qt 画图问题
比如说

C/C++ code

void A::paintEvent(QPaintEvent *)  {           QPainter p(this);     ...}

这玩意怎么调用的？

[解决办法]
当你使用update()或者repaint()函数时会自动调用，另assistant 助手你不用吗？：
This event handler can be reimplemented in a subclass to receive paint events passed in event.

A paint event is a request to repaint all or part of a widget. It can happen for one of the following reasons:

repaint() or update() was invoked,
the widget was obscured and has now been uncovered, or many other reasons.