[Qt-interest] QPaintEngine setSystemRect should not be changed while engine is active?

[Kermit Mei]

Hello community!

In my widget, I call update() in a timerEvent(QTimerEvent *event);
and then call a paint() function in paintEvent(QPaintEvent *event);

The code is like this:

void AnimationWidget::timerEvent(QTimerEvent *event) {
  if(event->timerId() == timerId)
      update();
}

void AnimationWidget::paintEvent(QPaintEvent *event) {
  if(timerId == 0)
    Widget::paintEvent(event);
  else
    paint(); //Do some paint event
}


Rum it, the system tell me:

QPaintEngine::setSystemRect: Should not be changed while engine is
active

How can I solve it? 


And also another question, if I run the program on ARM (embedded), the
last step in paint() can't show(). Why?

Thank you, very much!

CC: qt-embeded-interest