示例对应的制作的 ui文件 界面如下所示。

<?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>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <widget class="QWidget" name="verticalLayoutWidget">
   <property name="geometry">
    <rect>
     <x>40</x>
     <y>20</y>
     <width>77</width>
     <height>141</height>
    </rect>
   </property>
   <layout class="QGridLayout">
    <item row="0" column="0">
     <widget class="QPushButton" name="pushButton_1">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="text">
       <string>按钮1</string>
      </property>
     </widget>
    </item>
    <item row="1" column="0">
     <widget class="QPushButton" name="pushButton_2">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="text">
       <string>按钮2</string>
      </property>
     </widget>
    </item>
    <item row="2" column="0">
     <widget class="QPushButton" name="pushButton_3">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="text">
       <string>按钮3</string>
      </property>
     </widget>
    </item>
    <item row="3" column="0">
     <widget class="QPushButton" name="pushButton_4">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="text">
       <string>按钮4</string>
      </property>
     </widget>
    </item>
    <item row="4" column="0">
     <widget class="QPushButton" name="pushButton_5">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="text">
       <string>按钮5</string>
      </property>
     </widget>
    </item>
   </layout>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

from PyQt6.QtWidgets import QApplication, QMainWindow  
from PyQt6.uic import loadUi  
  
class MyWindow(QMainWindow):  
    def handleButtonClick_1(self, text):  
        print("1")
    def handleButtonClick_2(self, text):  
        print("2")
    def handleButtonClick_3(self, text):  
        print("3")
    def handleButtonClick_4(self, text):  
        print("4")
    def handleButtonClick_5(self, text):  
        print("5")
  
    def __init__(self, ui_file):    
        super().__init__()    
        # 使用 loadUi 加载 .ui 文件    
        loadUi(ui_file, self)    
    
        # 初始化窗口设置（如果需要）    
        self.setWindowTitle('My Window')
        
        # 确保对象名称与 .ui 文件中定义的名称完全匹配  
        self.pushButton_1.clicked.connect(self.handleButtonClick_1)
        self.pushButton_2.clicked.connect(self.handleButtonClick_2)
        self.pushButton_3.clicked.connect(self.handleButtonClick_3)
        self.pushButton_4.clicked.connect(self.handleButtonClick_4)
        self.pushButton_5.clicked.connect(self.handleButtonClick_5)
  
if __name__ == '__main__':    
    import sys    
    app = QApplication(sys.argv)    
    
    # 假设 untitled.ui 是你的 UI 文件，并且文件在同一目录    
    window = MyWindow('untitled.ui')    
    window.show()    
    
    sys.exit(app.exec())