我有这段代码：
import sys, random, pprint
from PyQt5 import QtWidgets, QtGui, QtCore
from PyQt5 import QtGui
from PyQt5.QtCore import Qt
class Window(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.setGeometry(QtCore.QRect(200, 200, 700, 700))
self.widget = QtWidgets.QWidget(self)
self.widget.setGeometry(QtCore.QRect(10, 10, 400, 200))
self.widget.setObjectName("widget")
def paintEvent(self, event):
painter = QtGui.QPainter()
painter.begin(self.widget)
self.drawPoints(painter)
painter.end()
def drawPoints(self, painter):
#drawing code
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
ex = Window()
ex.show()
sys.exit(app.exec_())
我期待什么：由drawPoints()绘制的区域（400x200）。 QWidget继承QPaintDevice。所以这段代码应该可行。但控制台说：
QPainter :: begin：Paint device返回引擎== 0，输入：1
QPainter :: end：画家未激活，已中止
请帮助我。
答案 0 :(得分：0)
看起来您正在尝试复制this example，对吗？
主要区别似乎是您为主窗口定义print(
df
.head(10)
.to_string(
formatters={"total_bill": "${:,.2f}".format,
"tip": "${:,.2f}".format
}
)
)
，而不是您实际尝试绘制的小部件。如果您创建了qi::int_parser<sint64, 10> dec64;
const qi::rule<const char *, sint64()> nsRule = dec64 >> qi::lit("ns");
const qi::rule<const char *, sint64()> usRule = dec64 >> qi::lit("us");
const qi::rule<const char *, sint64()> msRule = dec64 >> qi::lit("ms");
const qi::rule<const char *, sint64()> sRule = dec64 >> qi::lit("s");
const qi::rule<const char *, sint64()> mRule = dec64 >> qi::lit("m");
const qi::rule<const char *, sint64()> hRule = dec64 >> qi::lit("h");
auto result = qi::parse(f, f + length,
-hRule >>
-mRule >>
-sRule >>
-msRule >>
-usRule >>
-nsRule, h, m, s, ms, us, ns);
的自定义子类，在那里定义了<html>
<head>
<script type="text/javascript">
var timeleft = 5;
var mySpace = document.getElementById('space');
var myHeader = document.getElementById('header');
var downloadTimer = setInterval(function(){
timeleft--;
document.getElementById("countdowntimer").textContent = timeleft;
if(timeleft <= 0){
document.getElementById("space").style.display = "none";
document.getElementById("countdowntimer").style.display = "none";
document.getElementById("header").style.position = "initial";
clearInterval(downloadTimer);
}
},1000);
</script>
<style>
body {
margin: 0;
}
.header {
background-color: gray;
height: 10%;
top: 0;
width: 100%;
}
</style>
</head>
<body>
<div class="header" id="space"></div>
<div class="header" id="header" style="position:fixed">
<span id="countdowntimer">5</span>
</div>
<img src="http://scripts.semilo.com/mitchel/Weersverwachting.png" width="auto" height="auto">
</body>
</html>
，然后将其插入到标准paintEvent()实例中，它将起作用，如下所示：
QWidget至少，它不再打印该错误消息了。