如您所指出，paintEvent应该仅被覆盖。因此，一种方法是升级窗口小部件，您可以在以下答案中看到几个示例：
- https://stackoverflow.com/a/46616419
- https://stackoverflow.com/a/52131384
- https://stackoverflow.com/a/47273625
- https://stackoverflow.com/a/46671439
您必须具有以下结构：
├── main.py├── mywidget.py└── UI designer └── testUI.ui
在mywidget.py文件中，实现所需的类：
mywidget.py
from PySide2 import QtCore, QtGui, QtWidgetsclass Drawer(QtWidgets.QWidget): def paintEvent(self, e): """ the method paintEvent() is called automatically the QPainter class does all the low-level drawing pred between its methods begin() and end() """ qp = QtGui.QPainter() qp.begin(self) self.drawGeometry(qp) qp.end() def drawGeometry(self, qp): qp.setPen(QtGui.QPen(QtCore.Qt.green, 8, QtCore.Qt.DashLine)) qp.drawEllipse(40, 40, 400, 400)
然后，您必须使用Qt Designer打开.ui，右键单击窗口小部件并在上下文菜单中选择“提升为…”，然后在对话框中填写以下内容：
按添加按钮，然后按升级按钮，生成以下.ui文件
<?xml version="1.0" encoding="UTF-8"?><ui version="4.0"> <class>MainWindow</class> <widget name="MainWindow"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>731</width> <height>633</height> </rect> </property> <property name="windowTitle"> <string>MainWindow</string> </property> <widget name="centralwidget"> <layout name="verticalLayout"> <item> <widget name="graphicsView"> <property name="minimumSize"> <size> <width>0</width> <height>200</height> </size> </property> </widget> </item> <item> <widget name="widget" native="true"> <property name="minimumSize"> <size> <width>0</width> <height>250</height> </size> </property> <property name="maximumSize"> <size> <width>16777215</width> <height>300</height> </size> </property> </widget> </item> </layout> </widget> <widget name="menubar"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>731</width> <height>23</height> </rect> </property> </widget> <widget name="statusbar"/> </widget> <customwidgets> <customwidget> <class>Drawer</class> <extends>QWidget</extends> <header>mywidget</header> <container>1</container> </customwidget> </customwidgets> <resources/> <connections/></ui>
另一方面，QUiLoader仅加载Qt默认提供的小部件，因此，如果要使用新的小部件，必须覆盖createWidget方法：
main.py
import osimport sysfrom PySide2 import QtCore, QtGui, QtWidgets, QtUiToolsfrom mywidget import Drawerclass UiLoader(QtUiTools.QUiLoader): def createWidget(self, className, parent=None, name=""): if className == "Drawer": widget = Drawer(parent) widget.setObjectName(name) return widget return super(UiLoader, self).createWidget(className, parent, name)class MainForm(QtCore.QObject): def __init__(self, ui_file, parent=None): super(MainForm, self).__init__(parent) ui_file = QtCore.QFile(ui_file) ui_file.open(QtCore.QFile.ReadOnly) ### Load UI file from Designer ### loader = UiLoader() self.ui_window = loader.load(ui_file) ui_file.close() self.ui_window.show()if __name__ == "__main__": app = QtWidgets.QApplication(sys.argv) app.setStyle("Fusion") file = os.path.join( os.path.dirname(os.path.realpath(__file__)), "./UI designer/testUI.ui" ) form = MainForm(file) sys.exit(app.exec_())
