我在程序中定义了个Timer 每隔一段时间想更新一下 但是QPainter对象貌似只能在paintEvent中起作用 在Timer对应的slot中却无法使用 怎么也画不出来 是哪里出了问题呢？我的QPainter对象是私有成员 在paintEvent中初始化
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首先，Manual 中有比较明确的说明：
The common use of QPainter is inside a widget's paint event: Construct and customize (e.g. set the pen or the brush) the painter. Then draw. Remember to destroy the QPainter object after drawing.
Warning: When the paintdevice is a widget, QPainter can only be used inside a paintEvent() function or in a function called by paintEvent(); that is unless the Qt::WA_PaintOutsidePaintEvent widget attribute is set. On Mac OS X and Windows, you can only paint in a paintEvent() function regardless of this attribute's setting.
其次，在 paintEvent 中使用QPainter和你这儿的要求并不冲突。你在slot中update或repaint不就行了？