• PromoteLabelTest.py 提升的类

import sys
from PyQt5.QtWidgets import QApplication, QWidget,QVBoxLayout,QTextEdit,QPushButton,QHBoxLayout,QFileDialog,QLabel

class PromoteLabel(QLabel):
    def __init__(self,parent = None):
        super().__init__(parent)
        self.setText("111111")
        self.setStyleSheet("background-color:rgb(100,100,100);")

• T.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Form</class>
 <widget class="QWidget" name="Form">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>520</width>
    <height>431</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <widget class="PromoteLabel" name="label">
   <property name="geometry">
    <rect>
     <x>70</x>
     <y>120</y>
     <width>111</width>
     <height>61</height>
    </rect>
   </property>
   <property name="text">
    <string/>
   </property>
  </widget>
  <widget class="QPushButton" name="pushButton">
   <property name="geometry">
    <rect>
     <x>260</x>
     <y>200</y>
     <width>75</width>
     <height>23</height>
    </rect>
   </property>
   <property name="text">
    <string>PushButton</string>
   </property>
  </widget>
 </widget>
 <customwidgets>
  <customwidget>
   <class>PromoteLabel</class>
   <extends>QLabel</extends>
   <header>PromoteLabelTest</header>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

• Ui_T.py   .ui生成的

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'c:\Users\481073\Desktop\new\test.ui'
#
# Created by: PyQt5 UI code generator 5.15.9
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again.  Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(520, 431)
        self.label = PromoteLabel(Form)
        self.label.setGeometry(QtCore.QRect(70, 120, 111, 61))
        self.label.setText("")
        self.label.setObjectName("label")
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(260, 200, 75, 23))
        self.pushButton.setObjectName("pushButton")

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "PushButton"))
from PromoteLabelTest import PromoteLabel

• Public_Ui_test.py    逻辑层

from Ui_T import *
from PyQt5.QtWidgets import QApplication, QWidget,QVBoxLayout,QTextEdit,QPushButton,QHBoxLayout
from PyQt5.QtWidgets import QLabel

class LogicalLabel(Ui_Form,QWidget):
    def __init__(self,parent = None):
        super().__init__(parent)
        self.initUI()
    def initUI(self):
        self.setupUi(self)
        self.label.setText("22222")

• main.py   主函数

import sys
from PyQt5.QtWidgets import QApplication, QWidget,QVBoxLayout,QTextEdit,QPushButton,QHBoxLayout
from Public_Ui_T import *

class Demo(QWidget):
    def __init__(self):
        super(Demo, self).__init__()
        self.initUI()
 
    def initUI(self):
        self.setWindowTitle("...")
        self.resize(1200, 600)
 
        Vlayout = QVBoxLayout()
        MyLabel = LogicalLabel()
        Vlayout.addWidget(MyLabel)

        self.setLayout(Vlayout)
    
if __name__ == "__main__":
    app = QApplication(sys.argv)
    main = Demo()
    main.show()
    sys.exit(app.exec_())

• 效果